Abstract: A process for producing a solar cell is provided which can enhance the photovoltaic conversion efficiency by enlarging the grain sizes in the direction of the thickness of an i-layer to reduce grain boundaries, thereby avoiding recombination of carriers and activating the dopant at the same time. A process for producing a solar cell includes depositing at least a first transparent electrode, polycrystalline silicon layers in a PIN structure, and a second electrode in sequence on an electrically insulating substrate, the polycrystalline silicon layers in a PIN structure including a p-type silicon layer, an i-type silicon layer, and an n-type silicon layer, wherein the polycrystalline silicon layers in a PIN structure are formed by: forming a p-type, which is then subjected to thermal annealing; depositing an i-type silicon layer on the p-type silicon layer; and depositing an n-type silicon layer on the i-type silicon layer.