Effects of annealing on ion-implanted Si for interdigitated back contact solar cell

Abstract

Effects of annealing on the properties of P- and B-implanted Si for interdigitated back contact (IBC) solar cells were investigated with annealing temperature of from 950 to 1050 degrees C. P-implanted samples annealed at 950 degrees C were enough to activate dopants and recover the damage by implantation. As the annealing temperature was increased, the diode properties of P-implanted samples were degraded, while that of B-implanted samples were improved. However, in order to activate an implanted B ion, B-implanted samples needed an annealing of above 1000 degrees C. The implied V-oc of lifetime samples by quasi-steady-state photoconductance decay followed the trend of diode properties on annealing temperature. Finally, IBC cell was fabricated with a two-step annealing at 1050 degrees C for B of the emitter and 950 degrees C for P of the front and back surface fields. The IBC cell had V-oc of 618 mV, J(sc) of 35.1 mA/cm(2), FF of 78.8%, and the efficiency of 17.1% without surface texturing. (C) 2012 Elsevier B.V. All rights reserved.