Time-dependent hole and electron trapping effects in SIMOX buried oxides

The back-channel threshold shift associated with the buried oxide layers of separation by implanted oxygen (SIMOX) and zone-melted recrystallization (ZMR) field-effect transistors (FETs) was measured following pulsed irradiation as a function of temperature and back-gate bias using a fast time-resolved I-V measurement technique. The SIMOX FETs showed large initial negative voltage shifts at 0.2 ms after irradiation followed by temperature- and bias-dependent additional negative shifts to 800 s. Analysis and modeling of the results indicated: (1) efficient deep trapping of radiation-generated holes in the bulk of the oxide, (2) substantial initial trapping of radiation-generated electrons in the oxide, and (3) rapid removal of the trapped electrons by a thermal detrapping process. The ZMR FETs showed evidence of substantial trapping of holes alone in the oxide bulk.>