Radiation-tolerant, sidewall-hardened SOI/MOS transistors.

Total dose radiation effects were measured for sidewall-hardened n-channel SOI/MOS transistors, fabricated in zone-melt-recrystallized (ZMR) and oxygen-implanted (SIMOX) SOI materials. We compare the radiation responses of transistors with three types of edge configurations: island transistors with passivated edges, island transistors without passivated edges, and edgeless (enclosed-gate) transistors. Data from these three test devices allow clear separation of front-, back-, and edge-channel conduction. Passivated edge channels were hard to Sup (60) Co doses in excess of 24 Mrad (SiO sub 2). The overall hardness of the passivated-edge transistors is limited only by the radiation- induced threshold voltage shifts (about -1 V at 1.0 Mrad) of the top channel. No significant differences in total-dose response of ZMR and SIMOX devices were observed under the radiation conditions employed.