Heterojunction solar cell and manufacturing method thereof

Abstract

The invention provides a heterojunction solar cell and a manufacturing method thereof. The heterojunction solar cell comprises an N-type monocrystalline silicon wafer. A first intrinsic amorphous silicon layer, a third intrinsic amorphous silicon layer, an N-type amorphous silicon layer, a first transparent conductive film and a first electrode are sequentially formed on the front side of the N-type monocrystalline silicon wafer. A second intrinsic amorphous silicon layer, a fourth intrinsic amorphous silicon layer, a P-type amorphous silicon layer, a second transparent conducting film and a second electrode are sequentially formed on the back side of the N-type monocrystalline silicon wafer. The first intrinsic amorphous silicon layer and the second intrinsic amorphous silicon layer are formed through a first intrinsic PECVD process with the process gas being silane not doped with hydrogen. The third intrinsic amorphous silicon layer is formed through a second intrinsic PECVD process with process gases including carbon dioxide, hydrogen and silane, wherein the volume ratio of the carbon dioxide to the silane increases in a range of 0.1-0.6 as time increases. The fourth intrinsic amorphous silicon layer is formed through a third intrinsic PECVD (plasma enhanced chemical vapor deposition) process with process gases comprising hydrogen and silane. According to the invention, the cell conversion efficiency can be improved.

Description

technical field [0001] The invention relates to the field of solar cell manufacturing, in particular to a heterojunction solar cell and a manufacturing method thereof. Background technique [0002] Thin-film / crystalline silicon heterojunction solar cells (hereinafter referred to as heterojunction solar cells, also known as HIT or HJT or SHJ solar cells) belong to the third generation of high-efficiency solar cell technology, which combines the advantages of crystalline silicon and silicon thin films, and has With the characteristics of high conversion efficiency and low temperature coefficient, it will gradually replace PERC (Passivated Emitter and Rear Cell) cells and become the mainstream of photovoltaic cells. [0003] The core manufacturing process of heterojunction solar cells is the formation of various amorphous silicon films, including: the front and back sides of N-type crystalline silicon after surface texturing or texturing by plasma-enhanced chemical vapor deposi...

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Problems solved by technology

[0004] Each intrinsic amorphous silicon layer of the heterojunction solar cell made by the above prior art, especially the third intrinsic amorphous silicon layer located on the front side, has a relatively low energy conversion efficiency due to its narrow band gap.

In order to solve various problems caused by the narrow band gap of the intrinsic amorphous silicon layer in the prior art, some people in the industry make each intrinsic amorphous silicon layer into oxygen-doped hydrogenated amorphous silicon, although this can improve Bandgap width, but the actual passivation effect of hydrogenated amorphous silicon doped with oxygen to passivate the crystalline silicon texture is not good

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