Millisecond annealing for USJ dopant activation

By Debra Vogler, Senior Technical Editor

At a seminar at San Francisco’s Moscone Hall, a leading technologist surmised that millisecond annealing for USJ dopant activation will be pushed out to the 45nm node, but flash/RTA (rapid thermal annealing) or laser annealing will be needed at the 65nm node for poly depletion improvements.

John Borland, founder of J.O.B. Technologies, made this statement at the West Coast Junction Technology Group (WCJTG) seminar, where he was co-chair along with Susan Felch, program manager for USJ at Applied Materials, exploring “options for 45nm node USJ formation.”

Borland also reiterated his contention that SiON for gate dielectrics will be extended to the sub-45nm node for high-performance (HP) devices by increasing the percentage of nitrogen. He also is predicting that next year, low-standby power (LSTP) devices will use Hf SiON at the 65nm node, with the industry having to quickly increase the percentage of Hf.

Regarding strain engineering, Borland told WaferNews that in light of the failure of global strained-Si epitaxial techniques, the industry will have to move from localized strained-Si, where only a 1.5x improvement can be achieved, to Ge-channel formation in order to attain a mobility improvement of 2x-4x needed at the 45nm node.

Applied’s Felch told WaferNews that she presented data showing that “the combination of preamorphization, carbon, and dopant implants dramatically improves all of the USJ characteristics, including activation, junction depth, and abruptness – for both pMOS and nMOS dopants.” She also considers coimplantation processes followed by conventional spike anneal to be very promising candidates for USJ formation at the 65nm node and beyond.

Asked to comment on some of the most important news to come out of the seminar, Felch told WaferNews that millisecond annealing – both flash and laser – can minimize residual defects and junction leakage if very high annealing temperatures are used (e.g., greater than or equal to 1350C).

“Semiconductor manufacturers are beginning to generate good device results using these techniques – [and] molecular ion implantation, cluster ion implantation, and plasma doping continue to be promising, high-productivity methods of introducing ultrashallow layers of dopants,” she said.

The WCJTG is affiliated with the Northern California Chapter of the American Vacuum Society. In addition to the co-chairs, featured presenters were from Mattson, Axcelis, Varian Semiconductor Equipment Associates, Nissin, SemEquip, Epion, and Ultratech. – D.V.

(WN 12.31 August 15, 2005)


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