SiGe/SiGeC material

• Early Collaborators: ASU, Stanford Univ., HRL Laboratory, Auburn Univ., AFIT, Caltech, UC San Diego
• Extensive reactor and process modifications were required to control composition
• Strong academic and industrial interactions led to deep understanding of SiGeC
• Refined characterization, explored parameter space, added to fundamental understanding of SiGeC
• DARPA award -- Outstanding Small Business Contractor for 1997

• We have investigated a large portion of the SiGeC growth-parameter space (some accidental discoveries, too)
• Custom-designed growth process for each HBT structure
• All structures have better than ± 4 % thickness uniformity within wafer and wafer to wafer. Composition within SIMS detection limits
• Minimal oxygen content is standard for all processes, < 1E18 cm-3 (detection limit)

• SIMS profile of a Ge base profile, grading from 25% to 0%
• Lawrence Semiconductor Research Laboratory has developed a wide variety of SiGe profiles

• Carbon significantly suppresses boron out-diffusion from HBT base layers (also true for silicon-only layers)
• The addition of carbon can also reduce the stress in SiGe

• The following are boron diffusion profiles (SIMS analysis)

800 C 1/2 hr anneal