Impact of microcrystalline silicon carbide growth using hot-wire chemical vapor deposition on crystalline silicon surface passivation

摘要

Highly crystalline microcrystalline silicon carbide (mu c-SiC:H) with excellent optoelectronic material properties is a promising candidate as highly transparent doped layer in silicon heterojunction (SHJ) solar cells. These high quality materials are usually produced using hot wire chemical vapor deposition under aggressive growth conditions giving rise to the removal of the underlying passivation layer and thus the deterioration of the crystalline silicon (c-Si) surface passivation. In this work, we introduced the n-type mu c-SiC:H-type mu c-SiOx:H/intrinsic a-SiOx:H stack as a front layer configuration for p-type SHJ solar cells with the mu c-SiOx:H layer acting as an etch-resistant layer against the reactive deposition conditions during the mu c-SiC:H growth. We observed that the unfavorable expansion of micro-voids at the c-Si interface due to the in-diffusion of hydrogen atoms through the layer stack might be responsible for the deterioration of surface passivation. Excellent lifetime values were achieved under deposition conditions which are needed to grow high quality mu c-SiC:H layers for SHJ solar cells. (C) 2015 Elsevier B.V. All rights reserved.