Saturation phenomenon of stress-induced gate leakage current

The saturation phenomenon of stress-induced leakage currents (SILCs) is monitored with various stress voltages, gate oxide thicknesses and temperatures for gate oxides formed with different fabrication processes. It is found that there exist seeds of defects at the point when the gate oxide is fabricated and the number of the seeds determines the saturation phenomenon. Injected holes do not create new sites of defects, but help to activate the seeds of defects. Degradation models are proposed based on the percolation theory. In the presaturation region, defects in the body of the oxide are activated and SILC increases rapidly. The saturation phenomenon occurs when most of the seeds are activated. After saturation, many holes are used to create interface states and the increase of the SILC is suppressed.