PHYSICAL BACKGROUND OF SUBSTRATE CURRENT CHARACTERISTICS AND HOT-CARRIER IMMUNITY IN SHORT-CHANNEL ULTRATHIN-FILM MOSFETS/SIMOX

We show experimentally that, in contrast to past simulation results, I-SUB(max)/I-D decreases with decreasing silicon layer thickness. This is supported by two-dimensional numerical simulation results: the above phenomenon results from the nonlocal effect and the slightly gate-overlapped LDD structure. We also show that the velocity overshoot effect can suppress I-SUB(max)/I-D in short-channel MOSFET/SIMOX. It is demonstrated that 0.1-mu m-gate ultrathin-film nMOSFET/SIMOX will have a 10-year lifetime at the supply voltage of 1.6 V, although an abnormal degradation is indicated in such an extremely short-channel SOI device.