The effect of stress on metal semiconductor junctions

Abstract

The effects of stress on metal-semiconductor junctions have been investigated assuming that the transport mechanisms operative are thermionic emission, thermionic-field emission, or field emission. For generality the semiconductor has been considered to have a many valley conduction band structure. The analysis is developed in such a manner as to allow the calculation of the change in the built-in potential caused by the presence of a stress field from experimental data for several field configurations. Thus, it permits appraisal of the actual electron transfer process causing the stress-sensitivity in a given junction. For a material with a single valley structure in the conduction band, it is shown that the barrier height change is equal to the change in bias, at constant current, for any uniform stress field. For a loading applied normally to a portion of the contact an expression is also obtained for the barrier height change. For materials with a many valley structure, the same results are obtained for certain crystallographic directions; whereas, for others, repopulation effects are present. Their importance and magnitude are discussed.