Universal Passivation for p++ and n++ Areas on IBC Solar Cells

Abstract We present a universal passivation for both, phosphorus and boron doped surfaces of interdigitated back contact solar cells. The amorphous silicon layer shows excellent passivation on boron emitter and phosphorus back surface field as long as the deposition temperature is below T dep = 200°C. The amorphous silicon enables saturation current densities J o,em = 46 fA/cm 2 for laser doped p ++ boron emitters with sheet resistance R sh,em = 90Ω/sq as well as J o,bsf = 73 fA/cm 2 for laser doped n ++ phosphorus back surface fields with R sh,bsf °=°36°Ω/sq. Integration of the amorphous silicon low temperature passivation into our laser processed IBC solar cells yields a mean efficiency η = 22.8%. The open circuit voltage gain Δ V oc amounts to Δ V oc = 5 mV compared to cells with thermal silicon dioxide rear passivation. The best solar cells achieve a confirmed efficiency η = 23.24%.