A short-channel CMOS/SOS technology in recrystallized 0.3-µm-thick silicon-on-sapphire films

CMOS/SOS devices and circuits were fabricated in 0.3-µm-thick epitaxial silicon-on-sapphire (SOS) films. Two solid-phase epitaxial recrystallization techniques double solid-phase epitaxy (DSPE) and solid-phase epitaxy and regrowth (SPEAR) reduced the total microtwin concentrations in the Si layers more than tenfold, while increasing electron and hole inversion-layer mobilities between 30 and 45 percent. Leakage currents were substantially reduced in all SPEAR devices and in n-channel DSPE transistors, with some increase observed for p-channel DSPE devices. Drive currents and subthreshold slopes also showed significant improvement in both n- and p-devices. Propagation delays below 75 ps were obtained for CMOS/SOS inverters with Loff= 0.5 µm. The application of DSPE and SPEAR techniques to 0.3-µm SOS films will extend the scaling of CMOS/SOS to circuits with VLSI complexity.