Evaluation of Electrical Contact in Thin Semiconducting Films From AC Measurements

The electrical contact of metal-semiconductor (M-S) interface is normally evaluated using dc measurements like transfer of length model and volume transfer mode model. Preparation of these measurements needs high grade infrastructural facilities. Moreover, in the thin and nano-structure presences of surface states at the M-S interface perturb the dc results and led to the apparent conclusion. Influence of the surface states can be eliminated using the ac measurements. Considering M-S interface as a leaky capacitance a mathematical model has been developed in the present paper. Measuring M-S capacitance in three semiconducting films, e.g., n-Si, p-CdTe, and p-Cu2O and substituting these values in the developed model various parameters of the interface were evaluated. Results obtained by this method were compared with the results from dc measurements and these were comparable with each other. The scope of this paper is the application of this method to the laboratories lacking in high grade infrastructure.