SILICON-ON-SAPPHIRE TECHNOLOGY: QUO VADIS II A COMPETITIVE ALTERNATIVE FOR RF SYSTEMS

摘要

We have investigated the formation of high performance, device-quality, thin layers of silicon (30-50 nm) on sapphire (TFSOS) for application to mm-wave communication and sensors. The resulting TFSOS, obtained by Solid Phase Epitaxy (SPE), and the growth of strained silicon-germanium (SiGe) layers on these TFSOS have demonstrated enhanced devices and, hence, integrated circuits performance not achieved previously. We have fabricated 250 nm and 100 nm T-gated devices with noise figures as low as 0.9 dB at 2 GHz and 2.5 dB at 20 GHz, with G_a of 21 dB and 7.5 dB, respectively. 250 nm devices resulted in distributed wide-band amplifiers (10 GHz BW, world record) and tuned amplifiers (15 dB, 4 GHz BW). 100 nm devices produced VCOs (25.9 GHz), 30 GHz frequency dividers. We obtained f_t (f_(max)) of 105 GHz (50 GHz) for n-channel and 49 GHz (116 GHz, world record) for p-MODFETs (strained Si_(0.2)Ge_(0.8) on a relaxed Si_(0.7)Ge_(0.3) heterostructure). Cost comparisons with competing technologies are discussed.