Demonstrating distribution of SILC values at individual leakage spots

Stress induced leakage current (SILC) in the order of 10-17 to 10-13 A were statistically evaluated by using an advanced test circuit. In this paper, the distribution of SILC was evaluated by changing measurement electric fields, electric stress intensities, device area, and oxide thickness. The distribution of SILC is determined by the current values at individual leakage spots when the device area is sufficiently small. When the electric stress intensity and the measurement field are small, the distribution of logarithm of SILC follows the Gumbel distribution because the maximum current values of the leakage spots determine the gate leakage current in small area MOSFETs. We also evaluated the time-dependent characteristics of SILC in small area MOSFETs. The random telegraph signals of gate leakage current were observed which also indicates the current values of individual leakage spots.

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