The effect of heat treatment on spin-on oxide glasses in solar cell application

This paper studies the typical solar cell applications of spin-on silicate glass layers (Filmtronics Inc. 15A and 20B) in function of the applied heat treatment. The masking capability in wet etching procedures, like surface texturing and long-time anisotropic etching used in semitransparent solar cells, and also the surface passivation characteristics of p-type surfaces were examined. Optical microscopy inspections sustain the suitability in wet etching procedures of different temperature cured SOG layers. The best masking results in long-time anisotropic etching were gained for 800°C, N2 gas cured 20B layer. Microwave induced photoconductive decay (μ-PCD) measurements were conducted to reveal the lifetime changes that occur compared to raw material of differently passivated samples: Si3N4, SiO2 and spin-on glass layers cured at distinct temperatures. The measurements confirm a significant lifetime increase reached in case of 800°C, O2 gas cured 15A layer.