SERIES RESISTANCE CALCULATION FOR THE METAL-INSULATOR-SEMICONDUCTOR SCHOTTKY-BARRIER DIODES

An accurate way of determining the series resistance R(s) of Schottky Barrier Diodes (SBDs) with and without the interfacial oxide layer usi ng forward current-voltage (I-V) characteristics is discussed both the oretically and experimentally by taking into account the applied volta ge drop across the interfacial layer V-i. For the experimental discuss ion, the forward bias I-V characteristics of the SBDs with and without the oxide layer fabricated by LEC (the Liquid-Encapsulated Czochralsk i) GaAs were performed. The SBD without the oxide layer was fabricated to confirm a novel calculation method. For the theoretical discussion , an expression of V-i was obtained by considering effects of the laye r thickness and the interface state density parameters on forward bias I-V of the SBDs. The Value R(s) of the SBD with interfacial oxide lay er was seen to be larger than that of the SBD without the interfacial oxide layer due to contribution of this layer to the series resistance . According to the obtained theoretical formula, the value of V-i for the SBD with the oxide layer was calculated and it was subtracted from the applied voltage values V and then the value of R(s) was recalcula ted. Thus, it has been shown that this new value of R(s) is in much cl oser agreement with that determined for the SBD without the oxide laye r as predicted. Furthermore, the curves of the interface states energy distribution of each sample are determined. It was concluded that the shape of the density distribution curve and order of magnitude of the density of the interface states in the considered energy range are in close agreement with those obtained by others for Au/n-GaAs Schottky diodes by Schottky capacitance spectroscopy.