Solar cell with doped polysilicon surface areas and method for manufacturing thereof

A method for manufacturing a solar cell based on a silicon substrate (10;

• 60) with a front surface (13;
• 63) and a rear surface (11;
• 61), comprising:
• on at least the rear surface a polysilicon layer with at least one doped area of a first conductivity type (20;
• 28;
• 36;
• 66) in an area part of the polysilicon layer;
• on the front surface a doped layer of a second conductivity type (23;
• 40;
• 44;
• 56;
• 68) opposite to the first conductivity type;
• the method comprising:
• providing a silicon substrate of either the first conductivity type or the second conductivity type and having a front surface and a rear surface;
• creating a tunneling oxide layer (12;62) on at least a rear surface of the silicon substrate;
• depositing a polysilicon layer (14;
• 26;
• 34;
• 52;
• 64) on at least the rear surface;
• creating at least one doped area of the first conductivity type in an area part of the polysilicon layer on the rear surface, by exposing the area part to impurity species of the first conductivity type;
• forming in or on the front surface a doped layer of the second conductivity type based on exposing the front and rear surfaces of the substrate to impurity species of a second conductivity type opposite to the first conductivity type, in a manner that
• in the area part of the polysilicon layer on the rear surface, the polysilicon layer comprises impurities of the first conductivity type and impurities of the second conductivity type, in which a concentration of the impurity of the first conductivity type is larger than a concentration of the impurity of the second conductivity type, and
• the area part of the polysilicon layer on the rear surface has conductivity of the first conductivity type.