Model Development for Robust Design of SOI-MOSFET Circuits used in Radiative Environments

Circuits are exposed to increased particle strikes in an outer space environment. For this reason, thin-layer SOI-MOSFETs are mostly utilized to secure circuit functions under high radiation exposure. In the reported investigation, the main focus is given on the influence of the resulting carrier generation within the well in the silicon substrate, which has the purpose to preserve an accurate threshold-voltage control for the devices of the circuit. It is verified, that the generated carriers change the potential within the well in the same way as in the active SOI layer. However, 2D-device simulation reveals, that the flow of the generated carriers out from the well takes longer than that in the case of the SOI layer. The reason is, that the generated carriers are remained in the well even after the equilibrium condition is achieved within the device. This feature of the carrier flow in the well is nearly independent of the applied well bias. The ambipolar condition within the well, showing a huge amount of carrier concentration, is hardly modified only by the bias-potential applied. Even though carriers can flow to the neighboring well, this observed plasma condition is hardly changed.