CHARGE-CARRIER INJECTION INTO THE BURIED OXIDE OF WAFER-BONDED SILICON-ON-INSULATOR MATERIALS

The buried oxide of wafer-bonded silicon-on-insulator (SOI) materials was degraded by means of charge carrier injection into the oxide. Both Fowler-Nordheim injections using oxide fields above 7 MV/cm and ultra violet (UV) photoinjections were made. The injections were made using metal-oxide-semiconductor (MOS) capacitors formed after a complete rem oval of the silicon film. As a result of photoinjection the oxides of capacitors with bonded SiO2/SiO2 interfaces were charged resulting in a 0.3 V shift in the flatband voltage. For this group of capacitors Fo wler-Nordheim injection resulted in a strong positive charging of the oxide as well as in an increase of Si/SiO2 interface states. Capacitor s with bonded Si/SiO2 interfaces were found to be less degraded as a r esult of the charge injection as compared to capacitors with bonded Si O2/SiO2 interfaces. Secondary ion mass spectroscopy (SIMS) revealed a pronounced hydrogen peak at the bonded SiO2/SiO2 interface. The result s from the electrical and the SIMS investigations indicate that a bond ed SiO2/SiO2 interface is a highly defective region affecting the perf ormance of the MOS system.