Development of an In-Line Capable Sputtering Process of Silicon Nitride for Crystalline Silicon Solar Cells

Abstract

The purpose of this work is to develop a high rate sputtering process for the deposition of silicon nitride antireflection coatings for crystalline silicon solar cells. Our goal is to achieve a cycle time that allows for the processing of single wafers without a reduction of the production line throughput. We have varied several processing parameters such as process gas composition and individual gas flows into the process chamber as well as different deposition rates. In order to assess the performance of the deposited layers with respect to their passivation quality complete cells were processed on monocrystalline Czochralski wafers (125x125 mm2). We have found that the implementation of molecular hydrogen as a process gas has a detrimental effect on the passivation quality of the deposited layers. Furthermore, a clear influence of the sputtering rate on the overall cell performance can be seen. We have achieved a cell efficiency of 17.5% applying a standard screen printed process.