Abstract. For MOS diodes obtained by thermal oxidation of single crystal samples of n-InSb, the differential resitance in the region of avalanche breakdown is shown to be represented as a sum of two components: 1. Avalanche resistance, taking into account the dependence on the voltage of impact ionization of the surface impurity centres localized below the oxide and the effect of the space charge of the mobile carriers; 2. The resistance related to the variation of the impact ionization coefficient and of the reverse current as a function of temperature. In the regime of de?veloped breakdown, the heat action of the avalanche current produces an increase in the differential resistance with a constant value, independent of the current, as a result of which, a region with a positive slope is formed on the current-voltage characteristic. For sufficiently high values of the avalanche current and at a critical temperature, the avalanche breakdown becomes a thermal breakdown, known as a second breakdown with a typical sharp drop in voltage with a negligible variation of the current.

Full-text: PDF