Characterization of charge trapping processes in fully-depleted UNIBOND SOI MOSFET subjected to γ-irradiation

An investigation of radiation effect on edgeless accumulation mode (AM) p-channel and fully-depleted enhancement mode (EM) n-channel MOSFETs, fabricated on UNIBOND silicon on insulatior wafers (SOI), is presented in the paper. Characterization of trapped charge in the gate and buried oxides of the devices was performed by measuring only the front-gate transistors. It was revealed that the irradiation effect on EM n-MOSFET is stronger than that on AM p-MOSFET. Radiation-induced positive charge in the buried oxide proved to invert back interface what causes back channel creation in EM n-MOSFET but no such effect in AM p-MOSFET has been not observed. The effect of improving the quality of both interfaces for small irradiation doses is demonstrated

Radiation effect on electrical properties of fully-depleted UNIBOND SOI MOSFETS

A radiation effect on edgeless FD accumulation mode (AM) p-channel and inversion mode (IM) n-channel MOSFETs, fabricated on UNIBOND SOI wafers, is investigated. The method of second derivative is used to determine the threshold voltages of front and back channels in the MOSFETs from the measurements of front-gate transistors only. Stronger irradiation effect on IM n-MOSFET than that on AM p-MOSFET is revealed. It has been showed, that radiation-induced positive charge in the BOX inverted back interface causes back channel creation in IM n-MOSFET but no such effect in AM p-MOSFET has been observed. It is demonstrated that small-doses have the effect of improving the quality of both interface

High-Temperature Behavior of fully-Depleted SOI MOSFETS in Case of Charge Instability of Buried Oxide

Operation of fully depleted inversion mode SOI n-MOSFET, fabricated on UNIBOND wafers, in wide range of temperatures (25-320°C), was investigated. Observed kink in the IdVfg characteristics and unusual behavior of IdVd characteristics in case of the back-gate bias changing from negative to positive values was explained by model of positive charge (protons) generation at the substrate/BOX interface during negative back-gate bias applying, and fast ion drift towards the BOX/Si film interface at zero or positive back-gate bias, with the subsequent neutralization of this charge by electrons from back channel ofMOSFET. The neutralization can be driven by the front-gate voltage because of the charge coupling effect