DEGRADATION MECHANISMS OF THIN-FILM SIMOX SOI-MOSFET CHARACTERISTICS - OPTICAL AND ELECTRICAL EVALUATION

Optical and electrical measurements of thin film n-channel SOI-MOSFETs reveal that the exponential tail in photon emission spectra originate s from electron-hole recombination. Bremsstrahlung radiation model as a physical mechanism of photon emission was experimentally negated. Ne gative threshold voltage shift at the initial stage of high field stre ss is found to be caused by hole trapping in buried oxide. Subsequent turnover characteristics is explained by a competing process between e lectron trapping in the front gate oxide and hole trapping in the buri ed oxide. As to the degradation of transconductance, generated surface state as well as trapped holes in the buried oxide which reduce verti cal electric field in SOI film are involved in the complicate degradat ion of transconductance.