A method for forming doping regions, comprising: providing a substrate; forming a first-type doping material on the substrate; forming a second-type doping material on the substrate, wherein the first-type doping material is separated from the second-type doping material by a gap; forming a covering layer to cover the substrate, the first-type doping material, and the second-type doping material, wherein the covering layer is Al 2 O 3; and performing a thermal diffusion process to diffuse the first-type doping material and the second-type doping material into the substrate, wherein the step of forming the first-type doping material on the substrate comprises: providing a first mask comprising a first opening on the substrate; coating the first-type doping material on the mask and filling the first opening; performing a thermal process to convert the first-type doping material to a colloidal-state or solid-state compound; and removing the first mask; wherein the step of forming the second-type doping material on the substrate comprises: providing a second mask comprising a second opening on the substrate; coating the second-type doping material on the mask and filling the second opening; performing a thermal process to convert the second-type doping material to a colloidal-state or solid-state compound; and removing the second mask. providing a substrate; forming a first-type doping material on the substrate; forming a second-type doping material on the substrate, wherein the first-type doping material is separated from the second-type doping material by a gap; forming a covering layer to cover the substrate, the first-type doping material, and the second-type doping material, wherein the covering layer is Al 2 O 3; and performing a thermal diffusion process to diffuse the first-type doping material and the second-type doping material into the substrate, wherein the step of forming the first-type doping material on the substrate comprises: providing a first mask comprising a first opening on the substrate; coating the first-type doping material on the mask and filling the first opening; performing a thermal process to convert the first-type doping material to a colloidal-state or solid-state compound; and removing the first mask; wherein the step of forming the second-type doping material on the substrate comprises: providing a second mask comprising a second opening on the substrate; coating the second-type doping material on the mask and filling the second opening; performing a thermal process to convert the second-type doping material to a colloidal-state or solid-state compound; and removing the second mask. providing a first mask comprising a first opening on the substrate; coating the first-type doping material on the mask and filling the first opening; performing a thermal process to convert the first-type doping material to a colloidal-state or solid-state compound; and removing the first mask; wherein the step of forming the second-type doping material on the substrate comprises: providing a second mask comprising a second opening on the substrate; coating the second-type doping material on the mask and filling the second opening; performing a thermal process to convert the second-type doping material to a colloidal-state or solid-state compound; and removing the second mask. providing a second mask comprising a second opening on the substrate; coating the second-type doping material on the mask and filling the second opening; performing a thermal process to convert the second-type doping material to a colloidal-state or solid-state compound; and removing the second mask.