Study Of Diffusion Processes In The Production Of Crystalline Silicon Solar Cells

The further work on the development of PV technology attracted great supports from most countries of the world. One of the main efforts for crystalline silicon solar cells, which have already been commercialized, is to develop new technology and optimize the production processes for reducing the manufacturing cost. In this paper, the main topic is diffusion theory and process used in high throughput production lines for low cost crystalline silicon solar cells. The best process condition of diffusion is found in investigation on the relativity of diffusion process and the electronics parameters of solar cells in the manufacturing. Although there are lots of theories in this area, there is almost no domestic report about diffusion process in industrial production at all. So, it is important to do some research about it.In order to understand diffusion theories and process, the process principle and process steps of solar cells are described firstly. In this paper, the theories about diffusion and RTP (Rapid Thermal Process) in detail are analyzed. Then, the value of diffusion sheet resistance is set in the process program and the front probe of solar cell is designed in this article. The loss of power about probe design is calculated by investigating relative between sheet resistance and the spacing of screen grid.One of the best important problems is how to improve throughput during manufacturing solar cells with high conversion efficiency. For diffusion process, how to ensure the uniformity of diffusion is very important and it is to resolve throughput issue. In this paper, experiment methods are adopted for optimizing diffusion uniform by analyzing diffusion air-flowing environment. The air-flowing environment, which is comprised of quartz boat, quartz block, SiC paddle etc., is controlled difficultly. During the researching, the trial methods are applied and are effective for diffusion uniformity. To analyzing diffusion uniformity, the engineering model of air-flowing environment is brought forward firstly and is expounded for pre-feasibility study. These findings are very important on improving the quality of the products.The state of diffusion makes response to the electronics parameter of solar cell. Experiment method in this article validate the relation between diffusion and solar cells' capability, such as minority lifetime, open voltage, short circuit and firing condition. When diffusion process is further optimized, it can be used to produce high-efficiency crystalline silicon solar cells. Industrial solar cell manufacturing process, diffusion will bring many high-efficiency low-cost silicon cells coming to the future.