Determination of the Minority Carrier Surface Thermogeneration Rate in Metal-Oxide-Semiconductor Structures

Abstract

A metal-oxide-semiconductor (MOS) structure with the common field electrode insulated from the semiconductor by oxide layers h of different thicknesses allows the surface generation rate of minority charge carriers from current I(t) of nonequilibrium depletion state relaxation to be found. At the same time, it is possible in similar structures to observe the kinematics of electron-hole pair generation at the periphery of the field electrode (the edge generation effect). Measurements performed on an n-Si MOS structure with a stepwise change in oxide layer thickness (h 1 = 100 Å and h 2 = 3200 Å) allowed the generation rate at both the initial transient (t ~ 10 -5 s) stage of surface generation (4.34 × 10 10 cm -2 s -1 ) and at the basic extremely slow stage (10.4 cm -2 s -1 ) to be reliably determined for the first time. The estimated peripheral generation rate of minority charge carriers (holes) was 7.8 × 10 11 cm -2 s -1 .