Investigation of charge carrier injection in silicon nitride silicon junctions

Contactless measurements of the conductance of silicon wafers with silicon nitride top layers are presented. The deposition of silicon nitride layers leads to an increase of the conductance, both for p-Si and n-Si. This is attributed to the increase of the number of electrons in the Si wafer, in an inversion layer in p-Si, and in an accumulation layer in n-Si. Comparison of the increase of the conductance with the fixed charge density in the nitride layer points to a strongly reduced electron mobility in these layers. It is shown that the change of the conductance increases with growing thickness of the nitride layer up to a thickness of 20 nm, whereafter a constant value is attained. (C) 1996 American Institute of Physics.