Effect of reverse body bias on hot-electron-induced punchthrough reliability of pMOSFETs with thin gate dielectric at high temperatures

The effect of the reverse body bias VSB on the hot-electron-induced punch-through (HEIP) reliability of pMOSFETs with a thin gate dielectric at high temperatures was investigated for the first time. Experimental results indicate that the reverse VSB increased the HEIP degradation for a thin pMOSFET because of the increase in the maximum electric field Em due to the increase in the threshold voltage Vth. The sensitivity of HEIP degradation to VSB increased with increasing body effect coefficient γ at a given oxide thickness Tox. However, a thin device (22 Å) showed a much stronger dependence of HEIP degradation on VSB due to the decrease in the velocity saturation length l, although it had a smaller γ than a thick device (60 Å). These new observations suggest that the body bias technique for improving circuit performance can cause a reliability problem of nanoscale pMOSFETs at high temperatures and impose a significant limitation on CMOS device scaling.