A SIMPLE APPROACH TO THE CAPACITANCE TECHNIQUE FOR DETERMINATION OF INTERFACE STATE DENSITY OF A METAL-SEMICONDUCTOR CONTACT

In this study we attempt to interpret the experimentally observed noni deal Al-pSi Schottky diode I-V and C-V characteristics. The expression s for the capacitance-voltage relationship at low frequency and high f requency are derived considering two non idealities, namely interface states and series resistance. After extracting the diode parameters fr om the I-V and C-V characteristics, theoretical plots for the high fre quency and low frequency capacitance are obtained using the expression s derived. A comparison of the latter with available experimental plot s reveals that the expressions for the low frequency and high frequenc y capacitance derived here are simpler, more accurate and closer to ex perimental results than those used in the past. The variation of inter face state density with the applied bias voltage is obtained from the low frequency and high frequency C-V plots by using the capacitance te chnique. To examine the validity of the present approach, the value of density of interface states is compared with that obtained by the mul tifrequency admittance method. It is observed that there is good agree ment between the results obtained by both methods. (C) 1998 Elsevier S cience Ltd. All rights reserved.