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Power electronics based on gallium nitride (GaN) and silicon carbide (SiC) have the potential to significantly improve efficiency. But since these materials are higher-cost, companies need market-specific strategies in order to succeed as these new wide-bandgap (WBG) materials claim market share from silicon-based semiconductors, according to Lux Research.

Carmakers would succeed by playing the role of an “integrator,” by vertically integrating upstream in the value chain to power modules, while a GaN or SiC developer would do well to pursue a “technology disruptor” strategy, offering core technology expertise to solar inverter makers and incumbent system integrators like ABB.

“Fast-growing markets like automotive and solar inverters are unforgiving when it comes to players without strong business and strategy,” said Pallavi Madakasira, Lux Research Analyst and the lead author of the report titled, “Strategic Playbook for Power Electronics: Lessons from the IC Sector Evolution.”

“Start-ups trying to address these opportunities need to forge partnerships and collaborations — companies like Transphorm and GaN Systems that have done so are best-positioned for success,” she added.

Lux Research analysts evaluated the value chain in GaN and SiC power electronics to identify strategies for the automotive and solar inverter market. Among their findings:

  • Integrators face low risk. Carmakers could integrate upstream through acquisition to include power modules and inverter/converter manufacturing. Such acquisitions will allow carmakers to own drivetrain design and lower overall costs.
  • Tech differentiation is critical. A vertically integrated GaN/SiC device or module player is well-positioned in the solar value chain. The core technology differentiation that such a company offers will be critical for incumbent solar inverter makers like SMA and Fronius, and something system integrators like ABB do not have the competencies for.
  • Other players need to be nimble. Suppliers of substrates, packaging materials and thermal materials will need to customize. Staying nimble and planning for an increased number of specialized device makers in the power electronics value chain will be critical to their overall success.

The report, titled “Strategic Playbook for Power Electronics: Lessons from the IC Sector Evolution,” is part of the Lux Research Energy Electronics Intelligence service.

The Semiconductor Industry Association (SIA), representing U.S. leadership in semiconductor manufacturing and design, today announced that the global semiconductor industry posted record sales totaling $335.8 billion in 2014, an increase of 9.9 percent from the 2013 total of $305.6 billion. Global sales for the month of December 2014 reached $29.1 billion, marking the strongest December on record, while December 2014 sales in the Americas increased 16 percent compared to December 2013. Fourth quarter global sales of $87.4 billion were 9.3 percent higher than the total of $79.9 billion from the fourth quarter of 2013. Total sales for the year exceeded projections from the World Semiconductor Trade Statistics (WSTS) organization’s industry forecast. All monthly sales numbers are compiled by WSTS and represent a three-month moving average.

“The global semiconductor industry posted its highest-ever sales in 2014, topping $335 billion for the first time thanks to broad and sustained growth across nearly all regions and product categories,” said John Neuffer, president and CEO, Semiconductor Industry Association. “The industry now has achieved record sales in two consecutive years and is well-positioned for continued growth in 2015 and beyond.”

Several semiconductor product segments stood out in 2014. Logic was the largest semiconductor category by sales, reaching $91.6 billion in 2014, a 6.6 percent increase compared to 2013. Memory ($79.2 billion) and micro-ICs ($62.1 billion) – a category that includes microprocessors – rounded out the top three segments in terms of sales revenue. Memory was the fastest growing segment, increasing 18.2 percent in 2014. Within memory, DRAM performed particularly well, increasing by 34.7 percent year-over-year. Other fast-growing product segments included power transistors, which reached $11.9 billion in sales for a 16.1 percent annual increase, discretes ($20.2 billion/10.8 percent increase), and analog ($44.4 billion/10.6 percent increase).

Annual sales increased in all four regional markets for the first time since 2010. The Americas market showed particular strength, with sales increasing by 12.7 percent in 2014. Sales were also up in Asia Pacific (11.4 percent), Europe (7.4 percent), and Japan (0.1 percent), marking the first time annual sales in Japan increased since 2010.

“The U.S. market demonstrated particular strength in 2014, posting double-digit growth to lead all regions,” continued Neuffer. “With the new Congress now underway, we urge policymakers to help foster continued growth by enacting policies that promote U.S. innovation and global competitiveness.”

December 2014
Billions
Month-to-Month Sales
Market Last Month Current Month % Change
Americas 6.53 6.73 3.1%
Europe 3.19 3.01 -5.8%
Japan 2.93 2.80 -4.6%
Asia Pacific 17.12 16.59 -3.1%
Total 29.77 29.13 -2.2%
Year-to-Year Sales
Market Last Year Current Month % Change
Americas 5.80 6.73 16.0%
Europe 2.96 3.01 1.6%
Japan 2.93 2.80 -4.4%
Asia Pacific 14.96 16.59 10.9%
Total 26.65 29.13 9.3%
Three-Month-Moving Average Sales
Market Jun/Jul/Aug Sep/Oct/Nov % Change
Americas 6.06 6.73 11.1%
Europe 3.21 3.01 -6.4%
Japan 3.03 2.80 -7.7%
Asia Pacific 16.93 16.59 -2.0%
Total 29.23 29.13 -0.4%

Underdog DRAM


January 20, 2015

By Christian G. Dieseldorff, Industry Research & Statistics Group, SEMI

The DRAM sector experienced a major decline during and following the 2008-2009 financial crisis and eventually contracted — both the number of suppliers and installed fab production capacity. According to the SEMI World Fab Forecast Report, the outlook is now more positive as DRAM bit demand is on the rise and average selling prices improved in both 2013 and 2014.  Installed capacity is expected to emerge from negative to positive territory by the end of 2016, but factors for growth are complicated by complex technology issues.

For five years before the economic downturn, yearly growth rates for installed fab capacity trended in high double digits.  Looking back to 2007, eleven major companies produced DRAM chips in about 40 facilities globally, with installed capacity growing by 40 to 50 percent year-over-year from 2003 to 2007.

Since that time, the number of companies shrank from 11 players to six, with only 20 facilities in production and three major players (Samsung, Micron and SK Hynix) as the industry consolidated and contracted (see Figure 1 below, from SEMI World Fab Forecast report).  Qimonda, Promos and Powerchip left the scene, while Elpida and Rexchip were acquired by Micron. In addition, some front end fabs were converted from DRAM to Logic, Flash or other purposes.

SEMI--DRAM Facilities

Figure 1: Major DRAM companies (including Inotera) operating chip facilities (Source: SEMI, 2015)

The smaller number of key suppliers has stabilized the DRAM investment cycle and increasingly the manufacturers focus investments on market demand, not on production share gain. Meanwhile, DRAM bit demand is growing for applications such as mobile and infrastructure/servers.  One leading memory company has predicted CAGR of 27 percent for bit growth from 2013 to 2017.

Obstacle: New Paradigm is a Loss of Capacity

SEMI’s tracking of fab data reveal that when a company transitions a fab to the next leading edge technology there is a capacity loss.  Increased complexity and more process steps mean that these fabs produce fewer wafers per square foot of cleanroom.   This trend affects all industry segments, beginning at the 30/28nm node and smaller, and has been observed since 2012.  Depending on the age of the fab and product type, this loss can be significant, as much as 10-20 percent (See Figure 2).

Figure 2: Blue line shows that existing DRAM fabs lose capacity over time when transitioning to next technology node, while the red line shows new DRAM facilities adding capacity. (Source: SEMI, 2015)

Figure 2: Blue line shows that existing DRAM fabs lose capacity over time when transitioning to next technology node, while the red line shows new DRAM facilities adding capacity. (Source: SEMI, 2015)

SEMI’s World Fab Forecast report tracks nine fabs following this pattern: significant loss of capacity when transitioning to the next leading edge technology node.  From 2014 to 2016, existing DRAM fabs are expected to lose a total of about 25,000 wafers per month, every year when transitioning to next leading edge technology node.

To compensate for this and to meet expected bit demand, the industry is beginning to add new capacity with new fabs and lines. By 2015, three or four new fabs or lines will be in operation.  Of course, these will require time to ramp up; meaning that net capacity change likely will not shift from negative to positive territory until 2016, when about 3 percent growth is forecast.  Figure 3 illustrates how this could potentially affect worldwide DRAM capacity.

Figure 3: Worldwide DRAM capacity for Front End facilities in 300mm equivalent wafers per month and change rate in percent (Source: SEMI, 2015)

Figure 3: Worldwide DRAM capacity for Front End facilities in 300mm equivalent wafers per month and change rate in percent (Source: SEMI, 2015)

The worldwide loss of DRAM capacity from 2010 to 2014 is about 25 percent.  The loss of capacity due to technology upgrade kicks in about 2013 timeframe. Before that the loss is due to consolidations, closure and change of product types.

Obstacle: What’s Next, after 15nm?

Shrinking the DRAM nodes has become increasingly difficult.  As most companies produce in volume 30nm-25nm, some companies began already to offer 21/20nm node.  The next stage beyond that is only just being explored.  Will the industry see another shrink down to 1Ynm?  Or is this too challenging, and for most, not economically feasible?  Other technologies may move forward to eventually replace conventional DRAM, such as non-volatile memories like MRAM (Magnetic RAM), FeRAM (Ferro-electric RAM) and ReRAM (Resistive RAM), and PRAM or PCRAM (Phase-Change RAM).  As these technologies surface, DRAM capacity may be challenged again.

In summary, DRAM, the underdog, comes from behind and appears to promise positive growth by 2016. With the introduction of new technologies, it remains to be seen how DRAM capacity will be impacted and how much new wafer capacity will be needed. The SEMI World Fab Forecast Report lists over 40 facilities making DRAM products. Many facilities have major spending for equipment and construction planned for 2015. Learn more at www.semi.org/MarketInfo/FabDatabase  and www.youtube.com/user/SEMImktstats.

SEMI World Fab Forecast Report

SEMI’s World Fab Forecast reports lists over 40 facilities making DRAM products. 20 of these are dedicated DRAM facilities and over 30 of these have major spending in 2015 for equipment and construction.

The SEMI World Fab Forecast uses a bottom-up approach methodology, providing high-level summaries and graphs, and in-depth analyses of capital expenditures, capacities, technology and products by fab. Additionally, the database provides forecasts for the next 18 months by quarter. These tools are invaluable for understanding how the semiconductor manufacturing will look in 2014 and 2015, and learning more about capex for construction projects, fab equipping, technology levels, and products.

The SEMI Worldwide Semiconductor Equipment Market Subscription (WWSEMS) data tracks only new equipment for fabs and test and assembly and packaging houses.  The SEMI World Fab Forecast and its related Fab Database reports track any equipment needed to ramp fabs, upgrade technology nodes, and expand or change wafer size, including new equipment, used equipment, or in-house equipment. Also check out the Opto/LED Fab Forecast. Learn more about the SEMI fab databases at: www.semi.org/MarketInfo/FabDatabase and www.youtube.com/user/SEMImktstats

The SEMI Industry Strategy Symposium (ISS) opened yesterday with the theme “Riding the Wave of Silicon Magic.” The sold-out conference of the industry’s C-level executives highlighted favorable forecasts in the year’s first strategic outlook for the global microelectronics manufacturing industry.  The underlying drivers for growth and the next wave emerging from the Internet of Things (IoT) were discussed from several perspectives.

Opening keynoter Scott McGregor, president and CEO of Broadcom, traced the history of the industry’s more than 50 years of exponential improvements in silicon speed, power and design since Moore’s Law in 1965.  McGregor sees the next wave of Silicon Magic as a $15 trillion opportunity that will provide ubiquitous, nonstop, seamless high-speed connectivity.  Still, McGregor believes that three key issues challenge the industry’s growth.   First, patent reform, as patents are the foundation of the innovation economy and the global patent system does not meet today’s industry realities. Second, interoperability and standards, as IoT is raising the stakes for data privacy and security.  Finally, STEM education, as in the future, all businesses will be tech businesses.

In the Economic Trends session, presenters took on both macroeconomic and detailed industy-specific forecasts:

  • Nariman Behravesh, senior economist at IHS, presented the macroeconomic view of 2015 and the global implications brought on by the sharp drop in oil prices.  IHS predicted that the U.S. will grow in the 2.5-3.0 percent range in 2015 while other regions will be mixed: the European recovery will be slow, Japan’s economy will regain weak momentum, and China growth will continue to slow, but remain stronger than most. 
  • Mario Morales, VP at IDC, presented the 2015 semiconductor outlook. IDC saw the semiconductor market grow 7 percent in 2014 and projects 3.8 percent growth in 2015. Market growth will be led largely by automotive and industrial segments. 
  • Andrea Lati, principle analyst for VLSI Research, presented the 2015 semiconductor equipment outlook.  VLSI saw semiconductor equipment sales coming in at 17 percent growth in 2014 and forecasts 8 percent growth in 2015. VLSI noted the top 7 chipmakers accounted for 71 percent of spending in 2014 (vs. 56 percent in 2010). VLSI sees the consolidation driving an industry that has smaller cyclic peaks and is settling into a moderated two-year cycle cadence with fewer players having less incentive to individually make a market share grab.” 

Several presenters discussed the Internet of Things (IoT) and offered that the IoT provides an unprecedented growth opportunity — and understanding just what IoT is, at this stage, a challenge.  The lively session featured Frank Jones, VP and GM at Intel, David Ashley, VP of Customer Value Chain Management at Cisco Systems, Shawn DuBravac, chief economist and director of research at the Consumer Electronics Association (CEA), and Martin Reynolds, managing VP and fellow at Gartner.

Among the insights in the IoT session, Jones stressed that with all the IoT hype, it’s critical to demonstrate business value. Working with partners, he cited emerging IoT examples such as: saving 43 percent in time with an integrated “Smart Parking Solution” and improvements to Intel’s own factories with fab personnel defining a process step predictive maintenance tool (sensors and analytics) that saved $9 million per year.  Ashley made the point that with $19 trillion for the IoE at stake, the supply chain, including economic trends (labor wage inflation, government policy, shrinking life cycles) and ecosystem (supplier consolidation, visibility, consumer-driven technology) need to be addressed.  DuBravac focused on how everyday objects are becoming smarter and more connected and said that the key to technology should be what is meaningful as opposed to what is possible.

Days 2 and 3 at ISS will delve deeper into the underpinnings of the industry.  Technology and manufacturing insights will be discussed with presentations from:  TSMC, Altera, XMC, Intel, Honeywell, Micron, imec, ASE, IBM, Lux Research, Illumina, Cypress, Boing, and McKinsey.  A “Silicon Magic” panel will wrap up the conference with Intel, Lam Research, JSR, TSMC, and Qualcomm. The SEMI Industry Strategy Symposium (ISS) examines global economic, technology, market, business and geo-political developments influencing the semiconductor industry.

SUNY Polytechnic Institute (SUNY Poly) yesterday announced the SUNY Board of Trustees has appointed Dr. Alain Kaloyeros as the founding President of SUNY Poly.

“Dr. Alain Kaloyeros has led SUNY’s College of Nanoscale Science and Engineering since its inception, helping to make this first-of-its-kind institution a global model and position New York State as a leader in the nanotechnology-driven economy of the 21st century,” said SUNY Board Chairman H. Carl McCall. “It is only fitting that Dr. Kaloyeros be the one to build that model and bring it to scale through the continued development and expansion of SUNY Polytechnic Institute.”

“As the visionary who built CNSE into a world-class, high-tech, and globally recognized academic and economic development juggernaut, Dr. Alain Kaloyeros is the clear choice to lead SUNY Polytechnic Institute into the future,” said SUNY Chancellor Nancy L. Zimpher. “The unprecedented statewide expansion of the campus’ unique model and continued strong partnership with Governor Andrew Cuomo is testament to SUNY’s promise as New York’s economic engine and stature as an affordable, world-class educational institution. I am confident that, as its president, Dr. Kaloyeros will continue to build on SUNY Poly’s success and contributions to New York.”

“SUNY Polytechnic Institute is a revolutionary discovery and education model with two coequal campuses in Utica and Albany, and a key component of Governor Cuomo’s vision for high-tech innovation, job creation, and economic development in New York State.  I am privileged and humbled to be selected for the honor of leading this world-class institution and its talented and dedicated faculty, staff, and students,” said Dr. Kaloyeros.  “I would like to extend my sincere gratitude to the Governor, Chairman Carl McCall, the SUNY Board of Trustees, and Chancellor Nancy Zimpher for their continued confidence and support.”

Dr. Kaloyeros received his Ph.D. in Experimental Condensed Matter Physics from the University of Illinois at Urbana-Champaign in 1987.  A year later, Governor Mario M. Cuomo recruited Dr. Kaloyeros under the SUNY Graduate Research Initiative.  Since then, Dr. Kaloyeros has been actively involved in the development and implementation of New York’s high-tech strategy to become a global leader in the nanotechnology-driven economy of the 21st Century.

A critical cornerstone of New York’s high-technology strategy has been the establishment of the Colleges of Nanoscale Science and Engineering (CNSE) at SUNY Poly as a truly global resource that enables pioneering research and development, technology deployment, education, and commercialization for the international nanoelectronics industry.  CNSE was originally founded in April 2004 in response to the rapid changes and evolving needs in the educational and research landscapes brought on by the emergence of nanotechnology.  Under Dr. Kaloyeros’ leadership, CNSE has generated over $20B in public and private investments.

In 2014, CNSE merged with the SUNY Institute of Technology to form SUNY Poly, which today represents the world’s most advanced university-driven research enterprise, offering students a one-of-a-kind academic experience and providing over 300 corporate partners with access to an unmatched ecosystem for leading-edge R&D and commercialization of nanoelectronics and nanotechnology innovations.

 

Global shipments of diagnostic displays are forecast to grow at a 5 percent compound annual growth rate (CAGR), between 2014 and 2018. According to the latest DisplaySearch Specialty Displays Report, larger high-resolution wide-aspect-ratio displays are starting to become more popular, but 21.3-inch displays had a 67 percent share of unit shipments and a 65 percent share of revenues in the first half of 2014.

“The majority of future shipment growth will take place in emerging regions, not in developed regions, where much of the growth has previously occurred,” said Todd Fender, senior analyst professional and commercial displays for DisplaySearch, now part of IHS Inc. (NYSE: IHS). “At the county level, brands are looking to China, as the largest opportunity of growth, followed closely by Latin America.“

Fig. 1

Veteran radiologists who were trained on, and had previously read, images on traditional x-ray film using light boxes have been the driving force behind the continued strength of 21.3-inch displays with a 4:3 aspect ratio; however, as younger doctors enter the workforce, the legacy of film and grayscale-only images will slowly fade away. For example, in the first half of 2014, 43 percent of diagnostic displays were grayscale, but by 2018 these displays will represent just 34 percent of the market.

In today’s traditional picture archiving and communication (PACS) display ecosystem, multiple displays are used to review and read images; however, this configuration may lead to lower productivity and faster eye fatigue. Larger and higher resolution single screens have entered the market over the last few years, in an attempt to reduce or eliminate these issues. Displays with 6 megapixels (MP) to 10 (and higher) MPs are forecast to increase over the next several years, as users migrate from multiple screens to single-screen viewing.

Table 1

Clinical Review Displays and Surgical Displays

Similar to diagnostic shipments, clinical-review-display shipments are forecast to grow at a CAGR of 4 percent, between 2014 and 2018.  More than eight in 10 (83 percent) of clinical review display sizes fall between 19 inches and 22 inches, and 98 percent have a resolution of 2 MP or lower. “There will be a gradual shift to 4 MP and 8 MP wide aspect ratio displays as availability increases and as prices fall,” Fender said.

Surgical display shipments are forecast to grow more than any other medical-imaging category, reaching 7 percent CAGR between 2014 and 2018. Although almost half of surgical displays fall between 15 inches and 20 inches, the fastest area of growth is forecast to be in displays that 55 inches and larger, which are expected to grow at a 23 percent CAGR between 2014 and 2018. Additionally, 8 megapixel and 9 megapixel displays will grow significantly between 2014 and 2018; however, neither resolution will make up a large portion of the surgical display market.

“Larger displays are becoming more affordable, and they are being installed in surgical rooms as medical on-site and virtual professional collaboration becomes more popular,” Fender said. “Larger screens are much easier for multiple viewers, and many are also used as live teaching devices.”

LCD TV makers are responding to the challenge of OLED, with quantum dot (QD) technology, curved screens and other innovations. According to new information from DisplaySearch, now part of IHS Inc. (NYSE: IHS), in order to boost consumer value in the LCD television market, 4K ultra-high-definition (UHD) enhanced-color LCD TVs, using quantum dot (QD) technology will become available in 2015, with 1.3 million shipping worldwide. Shipments of quantum dot TVs are expected to grow to 18.7 million in 2018.

“While LCD technology undisputedly dominates the TV scene, manufacturers continue to innovate, in order to bring additional value to consumers,” said Paul Gray, director of European research at DisplaySearch. “The launch of new 4K UHD services promises to foment another round of innovation, as content creators bring richer, deeper colors to their art. Curved screens are also a popular feature this year, but there will be limited opportunity for growth, as the market for this feature is expected to peak next year.”

Based on information in the DisplaySearch Quarterly TV Design and Features Report, ITU-R Recommendation BT.2020 (rec.2020) colors promise a new level of fidelity that beyond the range of current high-definition TVs. “While broadcasters and cinematographers have begun to capture such images, the television industry has just started to respond to the challenge,” Gray said.

Fig 1

“Quantum dot is one of the weapons that the LCD industry is using to create ever more faithful images, which are very close to the full viewable range of the human eye,” Gray said. “Broadcasters are finalizing their plans for UHD, but they very clearly want there to be more to their UHD services than simply extra pixels. Richer colors work on any screen size, regardless of one’s visual acuity, and subtle shading increases the perception of reality. Quantum dot is part of the LCD industry’s response to the challenge posed by OLED technology and its use demonstrates that there is still room for innovation.”

Curved LCD TVs

A similar response to the challenge posed by OLED can be seen in the emergence of curved LCD TVs, which proves that LCD has further opportunities for innovation. In fact 1.8 million curved TVs are expected to ship in 2014, peaking at 8.2 million in 2016 and 2017. DisplaySearch analysts anticipate that Western Europe will be the dominant region for curved TVs, with 2.6 million shipping in both 2016 and 2017, resulting from consumer taste for unique design and Samsung’s dominant market share.

“Curved TVs are an industry styling fashion, in the same way that sets became very thin when the first LED backlights were introduced,” Gray said. “In due course, such fashions can burn through, leaving enduring value. For example, the legacy of thin TVs is their lower power consumption. It is easy to dismiss fashion, but it remains a critical element in maintaining value and consumer interest in the TV category.”

Fig 2

The Quarterly TV Design and Features Report tracks all 4K UHD TV product ranges, forecasts, video processing and broadcasting; plus, detailed information on other aspects of TV design such as smart TV, backlighting technology, OLED and 3D. This report is delivered in PowerPoint and includes Excel-based data and tables.

The Semiconductor Industry Association (SIA), representing U.S. leadership in semiconductor manufacturing and design, today announced that worldwide sales of semiconductors reached $29.7 billion for the month of November 2014, an increase of 9.1 percent from the November 2013 total of $27.2 billion and a slight decrease of 0.1 percent from the October 2014 total. Year-to-date sales through November are 10 percent higher than they were at the same point in 2013. All monthly sales numbers are compiled by the World Semiconductor Trade Statistics (WSTS) organization and represent a three-month moving average.

“Global semiconductor sales through November have matched the total from all of 2013, assuring that the industry will achieve a new record for sales in 2014,” said Brian Toohey, president and CEO, Semiconductor Industry Association. “Demand remains strong across nearly all semiconductor product categories, and the Americas and Asia Pacific regional markets continue to post the most robust growth. Macroeconomic trends bode well for continued growth into 2015.”

Regionally, year-to-year sales increased in the Asia Pacific (12.3 percent), the Americas (11.1 percent), and Europe (3.4 percent), but decreased in Japan (-4.5 percent). Sales were up compared to the previous month in the Americas (1.8 percent), but decreased slightly in Asia Pacific (-0.2 percent), Europe (-0.7 percent), and Japan (-2.6 percent). Sales were higher across all regions through November than they were through the same point last year.

The case is made for delivering liquid precursors from a central delivery system to the epi/dep tool as a vapor of precisely-controlled composition. 

By EGBERT WOELK, Ph.D., Dow Electronic Materials, North Andover, MA, USA and ROGER LOO, Ph.D., imec, Leuven, Belgium 

The epi and deposition processes for silicon-based semiconductor devices have used gaseous and liquid precursors. Gaseous precursors are compounds whose vapor pressure at room temperature is higher than 1500 torr (2000 mbar), which is sufficient to drive a mass flow controller (MFC). Using only one MFC, gaseous precursors can conveniently be metered to the process. Silane and dichlorosilane (DCS) have been used with that method. The industry has also used Trichloro silane (TCS) that boils at around 33°C and can be directly metered to a low pressure epi process using an appropriate MFC. For the epi of SiGe, germane, which is a gas, has been used.

Tetraethylorthosilicate (TEOS) has long been used for the deposition of SiO2 and has mostly been delivered using direct liquid injection (DLI). DLI meters the flow of the liquid precursor to a flash evaporator and provides good control, but flash evaporation requires high temperatures and care must be taken that the precursor compound does not break up prematurely. This can be a challenge for precursors that work at lower deposition temperatures.

More recently, trisilane (Si3H8) has been used for low temperature Si epi and deposition. The delivery of trisilane to the process uses the carrier-gas-assisted delivery method. In the most common implementation, it employs an on-board evaporation ampoule dedicated to one reactor. The same setup has been used for III-V compound semiconductor and LED epi with good success. Driven by cost pressure, however, the LED epi industry is moving from dedicated onboard ampoules to a central delivery system for high-volume precursors like trimethylgallium (TMGa). One part of the cost reduction simply comes from the economies of scale. Another aspect comes from the elimination of excessive hardware, such as thermal baths and pressure controllers, and their maintenance. Most importantly, a substantial part of the cost reduction comes from yield increases due to improved process control. The same central delivery system can be used for trisilane and other liquid CVD precursors for silicon-based CVD for similar cost reduction.

Carrier-gas-assisted precursor delivery

Liquid compounds with an RT vapor pressure between 1 and 400 mbar require carrier-gas-assisted delivery. Many liquid compounds within that vapor pressure range are excellent precursors for CVD and epi processes. For such compounds, the difference between the vapor pressure and the process pressure is too small to drive an MFC for straight metering. Adding a carrier gas increases the pressure to between approximately 760 and 1500 torr (1000 and 2000 mbar). The selection of a good delivery pressure depends primarily on the desired concentration.

The carrier-gas-assisted delivery method has long been used for trimethylgallium (TMGa) and trimethylaluminium (TMAl) for the growth of GaAs and GaN. For the growth of GaAlN and GaInN for LEDs, the composition ratio of the two group III precursors is extremely critical for the performance of the final product. Therefore, the precision of the evaporation and the metering has always been a concern.

FIGURE 1a shows the setup for a straight gas delivery and FIGURE 1b shows the setup for a carrier-gas-assisted delivery. The design shown in Figure 1b requires no modification of the epi/dep tool in order to accept a normally liquid precursor. From an epi/ dep tool perspective, the design shown in Figure 1b behaves just like the straight gas delivery of Figure 1a. As such, it allows the use of the gas mixture from one delivery system at several points of use, i.e. the output of the delivery system can be subdivided. In Figure 1b the precursor vapor is made on demand. While the output (mol flux of precursor per time) is theoretically unlimited, there are practical limits that restrict the output to approximately 20 standard liters per minute (slm). The main limitation is the dynamic range of the metering valve: the best units have a dynamic range of 1 in 104, which means that they can reliably control a flow between 0.002 and 20 slm. This is important for the mol flux precision at smaller flows, i.e. when only one or two tools draw precursor.

FIGURE 1a. High vapor pressure precursor, straight vapor delivery. S: pressure sensor, V: metering valve. S and V are normally integrated into a pressure regulator. MFC meters neat vapor.

FIGURE 1a. High vapor pressure precursor, straight vapor delivery. S: pressure sensor, V: metering valve. S and V are normally integrated into a pressure regulator. MFC meters neat vapor.

FIGURE 1b. Low vapor pressure precursor, carrier gas assisted delivery in Dow's VAPORSTATIONTM Central Delivery System. S: pressure sensor, V: metering valve. MFC meters diluted precursor vapor. Pressure and temperature control guarantee high precision concentration.

FIGURE 1b. Low vapor pressure precursor, carrier gas assisted delivery in Dow’s VAPORSTATIONTM Central Delivery System. S: pressure sensor, V: metering valve. MFC meters diluted precursor vapor. Pressure and temperature control guarantee high precision concentration.

On-board ampoules and central delivery system

There are several designs of carrier-gas-assisted delivery sources. The traditional design meters carrier gas into the ampoule rather than the mixture into the process chamber. Such a delivery system is dedicated to one reactor because the mass flow is metered upstream of the evaporation vessel and the associated MFC is controlled by the epi/dep tool. The ampoule serves two functions: (1) as the transport vessel and (2) as an evaporation device. For cost reasons, the ampoule should be of simple design. This means that trade-offs for the evaporation performance have to be made. The trade-offs result in line-to-line delivery rate variations and a noticeable change of delivery rate over the life of the ampoule. For some products, such changes require run-to-run recipe adjustments. In some cases the on-board ampoule is connected to a central dispense unit that transfers liquid precursor into the on-board ampoule. The result is a complex system that is still subject to delivery rate shifts requiring recipe adjustments.

A new central delivery system design is shown in Figure 1b. The task-optimized evaporator is fitted with temperature, pressure and level sensors that hold the precursor output variation at less than +/-0.4% by use of special stability algorithms. The evaporator is a permanently-installed part of the central delivery system. It is fed from a supply canister and features two precision thermometers inside the precursor liquid and gas distribution baffles and strainers for entrained droplets. Once calibrated, the system delivers a precisely known rate to a number of epi/dep reactors in the fab.

FIGURE 2 shows the output concentration of two calibrated central delivery units under various loads [1]. The curve that is alternately dotted and solid represents the signal of the binary gas sensor, which was alternately connected to one or the other unit. The other curves represent the output of the two units in standard liters per minute. The results show that proper calibration of the temperature and pressure sensors results in error of the delivery of less than +/- 0.4%. This precision cannot be achieved with ordinary on-board ampoules.

FIGURE 2. Output and concentration of two calibrated VAPORSTATIONTM Central Delivery Systems. Concentration remains within +/- 0.4% of set point regardless of load.

FIGURE 2. Output and concentration of two calibrated VAPORSTATIONTM Central Delivery Systems. Concentration remains within +/- 0.4% of set point regardless of load.

Recently, the application of the VAPORSTATION Central Delivery system has been expanded to deliver SnCl4 to a new process for the deposition of GeSn. It was fitted to a gas delivery line that was available on a mainstream silicon epi tool.

GeSn epi using a SnCl4 as new precursor

There has been increasing interest in GeSn and SiGeSn as alternative Group IV semiconductor material for electrical and optical device applications. The continuing expansion of traditional silicon with Sn and Ge offers additional design options for band gap and stress engineering. Over the past years, stress engineering using Ge made a major contribution to the improvement in Si-CMOS device performance. More recently the use of GeSn as a stressor for Ge-CMOS and relaxed GeSn as a virtual substrate, which is used to create tensile strain in a Ge epitaxial film, have been considered. The creation of tensile strain in an epitaxial Ge film is expected to result in germanium with a direct band gap [5] for photonic devices. Epitaxial Ge1-xSnx itself has also been considered as a promising candidate material for lasers and photodetectors. It has been predicted that, for sufficiently high Sn content, relaxed Ge1-xSnx turns into a direct band gap semiconductor [6,7]. Recent work of imec and its partners describe the active functionality based on the heterogeneous integration of strained GeSn/Ge on a Si platform providing photo-detection in the mid-infrared [8].

Due to the poor solubility of Sn in the Ge matrix of less than 1%, the epitaxial growth of (Si)GeSn is very challenging. Low solubility demands out-of- equilibrium growth conditions and, from epitaxial growth point of view, extremely low growth temperatures. Until recently, GeSn was grown by molecular beam epitaxy — a technique that is not suited for mass production. More recently, deuterated stannane, SnD4 has been used as Sn precursor for a CVD process, but the practical application is questionable due to the instability of SnD4.

To eliminate the problems posed by SnD4, imec chose to investigate stannic chloride SnCl4 , a stable, benign, abundant and commercially-available liquid Sn compound. Currently though, most of the CVD reactors for SiGeSn epi are not designed to use liquid precursor sources. In order to facilitate the use of liquid CVD precursors at imec, Dow Electronic Materials provided an R&D version of the central delivery system. It features the output stability and other benefits described above. The use of one of these units enabled imec to use SnCl4 and develop a groundbreaking new CVD process using digermane (Ge2H6) and SnCl4 to grow GeSn epitaxial films in a production-compatible CVD reactor. The films are metastable GeSn alloys with up to 13% substitutional Sn [10,11].

FIGURE 3 shows a typical cross section transmission electron microscope (TEM) picture with associated (224) x-ray diffraction reciprocal space mapping (XRD RSM) of a fully strained GeSn layer, grown on top of a relaxed Ge virtual substrate. The deposition temperature for the GeSn growth was kept low (320°C) in order to allow Sn incorporation in Ge lattice without Sn precipitation or agglomeration.

FIGURE 3. (a) Cross-section TEM of a 40 nm fully strained defect free GeSn layer on 1 lm Ge/Si buffer substrate with 8% Sn grown with AP- CVD using combination of Ge2H6 and SnCl4. (b) RHEED diagram of the Ge0.92Sn0.08 surface after deoxidation in UHV at 420°C. The pattern exhibits a strong (2x1) surface reconstruction along the [110]Ge direction. (c) (224) XRD-RSM of the 40 nm Ge0.92Sn0.08/Ge bilayer showing that GeSn is fully strained on Ge.

FIGURE 3. (a) Cross-section TEM of a 40 nm fully strained defect free GeSn layer on 1 lm Ge/Si buffer substrate with 8% Sn grown with AP- CVD using combination of Ge2H6 and SnCl4. (b) RHEED diagram of the Ge0.92Sn0.08 surface after deoxidation in UHV at 420°C. The pattern exhibits a strong (2×1) surface reconstruction along the [110]Ge direction. (c) (224) XRD-RSM of the 40 nm Ge0.92Sn0.08/Ge bilayer showing that GeSn is fully strained on Ge.

The TEM picture in Fig. 3(a) exhibits a defect-free and high crystalline quality for the 40-nm-thick GeSn layer. Furthermore, the surface quality of the as-grown Ge0.92Sn0.08/Ge/Si heterostructure was investigated by reflection high-energy electron diffraction (RHEED) analysis after ex-situ transfer to a MBE system. An annealing in ultra-high vacuum up to 420°C resulted in an oxide-free GeSn surface showing a strong (2×1) surface reconstruction as seen on RHEED pattern along the [110] azimuth (Fig. 3(b)). Finally, the XRDRSM around the (2 2 4) Bragg reflections (Fig. 3(c)) demonstrates that the grown GeSn layer is fully strained on Ge/Si (001) substrate.

Conclusion

The use of an improved delivery system for liquid CVD precursors allowed the
use of stannic chloride for the growth of GeSn. The new process developed by imec produces metastable GeSn with concentrations of substitutional tin of 13%.
TM Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow.

References

1. Control of vapor feed from liquid precursors to the OMVPE process, E. Woelk, R. DiCarlo, Journal of Crystal Growth, Available online 29 October 2013, In Press, Corrected Proof.
2. p and n-type germanium layers grown using iso-butyl germane in a III-V metal-organic vapor phase epitaxy reactor, R. Jakomin, G. Beaudoin, N. Gogneau, B. Lamare, L. Largeau, O. Mauguin, I. Sagnes, Thin Solid Films, 519, (2011), 4186–4191.
3. Crystalline Properties and Strain Relaxation Mechanism of CVD Grown GeSn, F. Gencarelli, B. Vincent, J. Demeule- meester, A. Vantomme, A. Moussa, A. Franquet, A. Kumar, H. Bender, J. Meersschaut, W. Vandervorst, R. Loo, M. Caymax, K. Temst, M. Heyns, ECS Trans. 50, (2013), 875-883.
4. Antimony surfactant for epitaxial growth of SiGe buffer layers at high deposition temperatures. Storck, P.; Vorder- westner, M.; Kondratyev, A.; Talalaev, R.; Amamchyan, A.; Woelk, E. Thin Solid Films vol. 518 issue 6 January 1, 2010. p. S23-S29.
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8. A. Gassenq, F. Gencarelli, J. Van Campenhout, Y. Shimura, R. Loo, G. Narcy, B. Vincent, and G. Roelkens, OPTICS EXPRESS 20 (25) , 27297 (2012).
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11. F. Gencarelli, B. Vincent, J. Demeulemeester, A. Vantomme, A. Moussa, A. Franquet, A. Kumar, H. Bender, J. Meerss- chaut, W. Vandervorst, R. Loo, M. Caymax, K. Temst, and M. Heyns ECS Journal of Solid State Science and Technology 2 (4), 134 (2013).
12. S. Gupta, B. Vincent, B. Yang, D. Lin, F. Gencarelli, J. Lin, R. Chen, O. Richard, H. Bender, B. Magyari-Koepe, M. Caymax, J. Dekoster, Y.; Nishi, and K. Saraswat, K. Extended Abstracts of the 2013 International Electronic Device Meeting (IEDM) (2012) p. 375.

EGBERT WOELK, PH.D., is director of marketing at Dow Electronic Materials, North Andover, MA. ROGER LOO, PH.D., is a principal scientist at imec, Leuven, Belgium.

By DAVE HEMKER, Senior Vice President and Chief Technology Officer, Lam Research Corp.

Given the current buzz around the Internet of Things (IoT), it is easy to lose sight of the challenges
– both economic and technical. On the economic side is the need to cost-effectively manufacture up to a trillion sensors used to gather data, while on the technical side, the challenge involves building out the infrastructure. This includes enabling the transmission, storage, and analysis of volumes of data far exceeding anything we see today. These divergent needs will drive the semiconductor equipment industry to provide very different types of manufacturing solutions to support the IoT.

In order to fulfill the promise of the IoT, sensor technology will need to become nearly ubiquitous in our businesses, homes, electronic products, cars, and even our clothing. Per-unit costs for sensors will need to be kept very low to ensure the technology is economically viable. To support this need, trailing-edge semiconductor manufacturing capabilities provide a viable option since fully depreciated wafer processing equipment can produce chips cost efficiently. For semiconductor equipment suppliers, this translates into additional sales of refurbished and productivity-focused equipment and upgrades that improve yield, throughput, and running costs. In addition to being produced inexpensively, sensors intended for use in the IoT will need to meet several criteria. First, they need to operate on very low amounts of power. In fact, some may even be self-powered via MEMS (microelectromechanical systems)-based oscillators or the collection of environmental radio frequency energy, also known as energy harvesting/scavenging. Second, they will involve specialized functions, for example, the ability to monitor pH or humidity. Third, to enable the transmission of data collected to the supporting infrastructure, good wireless communications capabilities will be important. Finally, sensors will need to be small, easily integrated into other structures – such as a pane of glass, and available in new form factors – like flexible substrates for clothing. Together, these new requirements will drive innovation in chip technology across the semiconductor industry’s ecosystem.

The infrastructure needed to support the IoT, in contrast, will require semiconductor performance to continue its historical advancement of doubling every 18-24 months. Here, the challenges are a result of the need for vast amounts of networking, storage in the Cloud, and big data analysis. Additionally, many uses for the IoT will involve risks far greater than those that exist in today’s internet. With potential medical and transportation applications, for example, the results of data analysis performed in real time can literally be a matter of life or death. Likewise, managing the security and privacy of the data being generated will be paramount. The real-world nature of things also adds an enormous level of complexity in terms of predictive analysis.

Implementing these capabilities and infrastructure on the scale imagined in the IoT will require far more powerful memory and logic devices than are currently available. This need will drive the continued extension of Moore’s Law and demand for advanced semiconductor manufacturing capability, such as atomic-scale wafer processing. Controlling manufacturing process variability will also become increasingly important to ensure that every device in the new, interconnected world operates as expected.

With development of the IoT, semiconductor equipment companies can look forward to opportunities beyond communications and computing, though the timing of its emergence is uncertain. For wafer processing equipment suppliers in particular, new markets for leading-edge systems used in the IoT infrastructure and productivity-focused upgrades for sensor manufacturing are expected to develop.