The invention belongs to the technical field of
solar cell manufacturing, and relates to a step-by-step
phosphorus doping method of a high-efficiency and low-cost
crystal silicon cell, namely a primary depletion
diffusion combined with secondary high-concentration shallow layer
diffusion and back
etching method. By controlling the flow of
oxygen, A low-temperature low-
phosphorus source depositionis carry out for that first time on a p-type
silicon substrate by
nitrogen flow rate and
phosphorus oxychloride flow rate, After a long time of high temperature propulsion, the phosphorus in the
phosphor-
silicate glass is exhausted, and the low
surface concentration layer n + is realized. The second time, the
phosphor-free glass is deposited on the
phosphor-
silicate glass, and the
high surface concentration layer n + + is pushed to form a very thin
high concentration layer, which can be quickly etched off by means of back
etching. The method can accurately control the
phosphorus doping distribution in different regions independently to ensure that the non-
electrode region has low
doping concentration and low
recombination current so as to ensure higher open-circuit
voltage. The
electrode region has high
doping concentration, which forms good
ohmic contact with the
metal electrode and ensures that the
filling factor is not lost, so as to improve the
photoelectric conversion performanceof the battery as a whole.