TABLE OF CONTENTS Silicon on insulator substrates have been a potential replacement for bulk silicon for next generation CMOS circuits for two decades; however, bulk silicon has been able to hold off the challenge thanks to advances in processing and device architectures. However, now that high quality, lower cost SOI substrates are commercially available and as the ITRS [34] includes targets for SOI materials the long-term prospect for SIMOX is much improved. Commercial SIMOX ICs are on the market and the shift from thick to thin film SOI substrates is now gaining pace. It is noted that recent advances in processing of thin BOX structures has been achieved by careful matching of the O + ion energy and dose and by optimising the anneal ambient and ramp rate. These developments pave the way to higher quality substrates and still lower processing costs.
It is noteworthy that the authors [108] of a recent (2002) critical appraisal of the three principal SOI materials technologies (SIMOX, Unibond [95] and ELTRAN [82]) have identified SIMOX as their preferred technology as, they argue, the substrates are less expensive, manufacture is by an inherently simple process and the technology already has widespread industrial acceptance.
The physics and chemistry of the SIMOX process are largely understood and volume manufacture of high quality SIMOX/SOI substrates is now becoming a reality with the wafer vendors optimistic that the targets specified in the ITRS for the next generation of CMOS SOI circuits can be adequately met. However,...
