Improved SOS by rapid thermal annealing and solid phase epitaxial regrowth

Summary form only given. CMOS circuits made from conventional SOS material frequently suffer from high bulk and back channel leakage. An attempt has been made to improve the quality of the bulk material by a combination of rapid thermal annealing (RTA) and solid-phase epitaxial regrowth (SPEAR). The baseline, the RTA, and the RTA/SPEAR SOS layers were examined for Al redistribution by secondary ion mass spectrometry and spreading resistance measurements. The quality of the material was examined by Rutherford backscattering and transmission electron microscopy. Electrical evaluation was done by wafer mapping using four point probe sheet resistance and contactless sheet conductance using Lehighton probes. Channel mobilities were measured using MOSFETs fabricated on these materials. High-temperature RTA increases the Al content of the material, which can be removed by subsequent processing. In most samples, however, Al distribution was found to be patchy. The Al content of the processed RTA/SPEAR samples was much lower than that in any conventionally processed SOS material.<
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