Electrical evaluation of innovating processes for improving SOS materials

Recent variants of silicon on sapphire films, prepared using three techniques (solid-phase epitaxial regrowth, two-step epitaxial growth and double implant), are investigated in terms of material and device properties. The pseudo-MOSFET analysis shows that the threshold voltage, electron mobility and trap density at the back Si–Al 2O 3 interface are greatly improved by the new processes. The results are confirmed by device characterization, which shows good properties of the front-channel and Si–SiO 2 interface and low short-channel effects in doped and ‘undoped’ MOSFETs.