CVD Boron Containing Glasses - An Attractive Alternative Diffusion Source for High Quality Emitters and Simplified Processing : A Review

Abstract

This review presents the current state of the art and interesting questions with regard to CVD BSG layers. The advantages of CVD doping sources over the conventional POCl₃ and BBr₃ or BCl₃ gaseous sources are the simple way to deposit a diffusion source on only a single side of the wafer and structuring the diffusion source to achieve dopant concentration profiles next to each other on the same side of the wafer. In addition, these CVD glasses are multifunctional. The same CVD BSG can serve e. g. as doping source, passivation layer, antireflective coating and as electrical insulator.<br /><br />Monofacial n-type solar cells achieve efficiencies up to 20.5% on a 156 x 156 mm² n-type Cz-Si solar cell. Bifacial cells of that size show efficiencies up to 20.1%. Back junction back contact cells show an efficiency of 20.5% on 4 cm2 aperture area.