Process of manufacturing an interdigitated back-contact solar cell
AssigneeNational Tsing Hua University
InventorLi-karn Wang
Life of this patent
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Abstract
A process of manufacturing the interdigitated back-contact solar cell, with the use of screen printing or spraying and the use of chemical etching, forms the trenches for the P-type electrode on the back of the substrate for making the solar cell. The time-consuming process of photolithography (for example, at least two steps of high-temperature diffusion) can be avoided. Furthermore, only one machine for printing and etching is needed to form the structure of the interdigitated back-contact solar cell. The present invention can make the whole process time-efficient and low-cost to enhance the efficiency of the solar cell, fulfilling the demand of mass production.
Claims13
A process of manufacturing an interdigitated back-contact solar cell, comprising at least the following steps:
- (F) providing a semiconductor substrate having a micro-structure surface, forming a heavily doped N++ semiconductor layer on a front side and a back side of said semiconductor substrate, wherein a chemical-resistant mask layer is coated on the back side of said semiconductor substrate by screen printing or spraying to form a first mask layer;
- said semiconductor substrate is placed into a chemical etching solution to remove a certain thickness of said heavily doped N++ semiconductor layer on a front side of said semiconductor substrate so that the heavily doped N++ semiconductor layer on the front side of said semiconductor substrate becomes a lightly doped first N-type semiconductor layer;
- and said first mask layer is removed;
- (G) performing a screen printing or spraying process to form, respectively, a second mask layer on the front side of said semiconductor substrate to cover said first N-type semiconductor layer, and to form a patterned third mask layer on the back side of said semiconductor substrate, so that the N++ semiconductor layer on the back side of said semiconductor substrate is partially exposed while the unexposed part of the N++ semiconductor layer is protected by said third mask layer;
- (H) etching the interior of the semiconductor substrate by using a chemical etching solution to form a plurality of trenches in the exposed part of the N++ semiconductor layer, and the unexposed part of the N++ semiconductor layer protected by said third mask layer is less susceptible to etching, or is completely un-etched, maintaining the function of back surface field, wherein the unexposed part of the N++ semiconductor layer protected by said third mask layer forms a second N-type semiconductor layer, meanwhile said first N-type semiconductor layer on the front side of said semiconductor substrate is protected by said second mask layer, maintaining the function of front surface field;
- (I) removing said second and third mask layers, and then coating an antireflection layer on the front side of said semiconductor substrate;
- and
- (J) forming a P-type metal electrode and an N-type metal electrode by printing, respectively, in the trench and at a part of the area of said second N-type semiconductor layer, and then forming a P-type semiconductor layer at a part of the bottom or at the whole bottom of each trench through co-firing so that said P-type metal electrode and said N-type metal electrode both form good electrical contact with said semiconductor substrate in the fabrication of the interdigitated back-contact solar cell.
Dependencies are inferred from the claim text.