Diffusion method and solar cell manufacturing method

The embodiment of the invention provides a diffusion method and a solar cell manufacturing method, the diffusion method comprises at least two diffusion processes, and each diffusion process further comprises the following steps: under the condition that a silicon wafer is put into a diffusion furnace, introducing a source into the diffusion furnace to carry out phosphorus diffusion on the silicon wafer, heating the diffusion furnace to enable phosphorus to be propelled into the silicon wafer, and cooling the diffusion furnace based on the temperature of the temperature rising tail end, introducing oxygen during cooling to carry out variable-temperature oxygen-containing propulsion on the silicon wafer, and after at least two steps of source introduction propulsion processes are carried out, opening the diffusion furnace to take out the silicon wafer after cooling the diffusion furnace. In the variable-temperature oxygen-containing propulsion process, the phosphorus diffusion speed can be reduced through cool