Self-Assembled Monolayers for Silicon Passivated Contacts

Abstract

We present the application of self assembled monolayers (SAM) produced from hexamethyldisilazane (HMDS), to the polysilicon/tunneling SiCh interface as well as the external surface for application to silicon passivated contact solar cells. By immersing tunnel SiCh on cSi in the HMDS solution, almost complete trimethylsilyl coverage is achieved. This provides better adhesion for PECVD grown a-Si:H due to the presence of carbon, and subsequent high temperature crystallization does not lead to blistering, nor degrade surface or bulk passivation. This is demonstrated on passivated contact solar cells and symmetric structures. Furthermore, an HMDS functionalized surface is resistant to HF and TMAH etchants, but can be patterned with UV light, creating a selective mask template for subsequent wet etch.