Process-Property Relationships For a-Si1-xCx:H Deposition: Excursions in Parameter Space Guided by Real Time Spectroellipsometry

Abstract

ABSTRACTReal time spectroellipsometry (RTSE) has been applied to study the growth of a-Si1-xCx:H alloys (x∼0.1; Eg=1.90–2.00 eV) for applications as i- and p-type layers in wide band gap solar cells. Two important material parameters, the optical gap and the relative bond-packing density (or void volume fraction), can be estimated from RTSE data collected during the growth of a sequence of layers onto the same substrate using different plasma-enhanced CVD conditions. In this way, large regions of parameter space have been scanned expeditiously, and an improved understanding of the effects of H2-dilution, substrate temperature (Ts), plasma power, gas pressure, and gas flow on the film properties has been obtained.