The surface generation hump in irradiated power MOSFETs

A method of quantifying near midgap-level interface traps, capture cross section, and changes in oxide-trapped charge using a surface generation hump in the subthreshold curve (I/sub d/ vs. V/sub g/) of power MOSFETs is developed. The surface generation hump is a result of the generation of carriers from traps at the depleted Si-SiO/sub 2/ interface in a gated diode-type structure. The charge neutrality point of the hump is determined, and shifts of this point are due solely to changes in oxide-trapped charge. Another point is used to determine the stretchout of the hump, and thus the interface trap density. With the interface trap density determined, the capture cross section is extracted from the surface generation velocity.<>