Impact of boron rich layer on performance degradation in boric acid diffused emitters for n-type crystalline Si solar cells

Abstract

Boron rich layer (BRL) formed beneath the borosilicate glass layer during p-type emitter formation is an undesirable phenomenon. It influences different cell parameters and can degrade the device performance. In this work, the device degradation study is done for different BRL thicknesses produced with different concentrations of the boric acid dopant source. The bulk carrier lifetime reduces to more than 75% and emitter saturation current density becomes more than 10−12 mA cm−2 for 60 nm of BRL thickness. The observed Jsc and Voc values become zero for BRL thicknesses higher than 40 nm as seen in this work and the device properties could not be enhanced. So, higher thicknesses of BRL should be avoided.