N-type multicrystalline silicon solar cells with BBr₃-diffused front junction

A simplified laboratory process with one photolithographic step for front junction solar cells on n-type multicrystalline (mc) silicon has been developed. The emitter diffusion is done in an open tube furnace with BBr3 and back-surface-field diffusion using POCl3, loading the wafers front-to-front and back-to-back respectively and thus avoiding additional etching steps. The front surface has been passivated by a 10 nm thermal oxide grown in a tube furnace. With this simple process, efficiencies of 11.0% on n-type mc-Si and 11.5% on n-type Cz-Si have been realized without antireflection coating and without surface texture. Applying a double layer antireflection coating (DARC) on these cells, efficiencies of 16.4% on Cz-Si and 14.7% on mc-Si have been achieved