Experimental Evaluation of Parasitic Bipolar Effects and Mechanical Stress Effects in SOI-Power-MOSFETs

Abstract

This paper reports on an experimental evaluation of mechanical stress effects in SOI (Silicon on Insulator) power devices. In particular, this study focuses on the interaction of parasitic bipolar effects which are unique physical phenomenon of SOI-type devices. The electrical characteristics of SOI-power-nMOSFETs (power n-type Metal-Oxide-Semiconductor Field-effect-transistors) under mechanical loading are measured using a four-point bending method. It is demonstrated that the parasitic bipolar effects may accelerate the electrical variation induced by the mechanical stress effects. In addition, the experimental results show the following:

• There may be a load direction dependence in the drain conductance change under the parasitic bipolar region.

• Gate-length dependence is not clarified.