Voltage Ramp Stress Test to determine TDDB performance in SRAM vehicle

We applied Voltage Ramp Stress Test (VRST) to an SRAM test vehicle and compared the obtained Vfail distribution with theoretical predictions from various TDDB failure criteria. Measured Vfail results are matched with the prediction from TDDB failure criterion of Ig/Ig0=1000 or more. We developed a numerical method to predict effective Igate with TDDB stress. It was applied to VRST condition and shows good agreement with measured data.