High temperature operation of ISE devices and circuits

Summary form only given. The high-temperature behavior of devices and circuits fabricated in ISE (isolated silicon epitaxy) SOI wafers and in bulk Si wafers is discussed. The advantages of SOI over bulk circuits under high-temperature operation result from reduced leakage current due to the absence of well junction in CMOS and the reduction of source and drain to body junction areas. One to two orders of magnitude reduction of leakage current for ISE devices compared to equivalent bulk devices is observed at 300°C. At this temperature, junction leakage in bulk devices reaches several tens of microamps. These results indicate the leakage at high temperature is dominated by the diffusion of carriers through junctions (proportional to n_i²(T)). Another confirmation of this observation is provided by the recovery time of drain-source transient of a depletion-mode MOSFET as a function of temperature when a step bias is applied to the gate