Radiation-hardened n-channel MOSFET achieved by a combination of polysilicon sidewall and SIMOX technology

A radiation-hardened n-channel MOSFET has been developed by a combination of a polysilicon sidewall and SIMOX technology. The MOSFET is laterally isolated by multilayers of sidewall SiO2, sidewall polysilicon and field SiO2, It is vertically isolated by multilayers of highly oxygen-doped polysilicon and buried oxide. By using this isolation structure and a thin gate oxide, an increase in leakage currents and a threshold voltage shift were suppressed to less than 1.5 orders of magnitude and 0.08 V, respectively, after 106 rad(Si) irradiation.