The use of targets in the photovoltaic field is mainly thin-film batteries and HIT photovoltaic cells. Solar cells mainly include crystalline silicon cells and thin-film cells. The target material is mainly used in the back electrode of thin-film solar cells and the conductor layer of HIT (heterojunction) cells. According to different production processes, crystalline silicon solar cells can be divided into silicon wafer coated solar cells and PVD process high conversion silicon wafer solar cells. Among them, the production of silicon wafer coated solar cells does not use sputtering targets. At present, the main targets are It is used in the field of solar thin-film batteries, and HIT, as a future alternative technology for PERC (passivated emitter and back local contact battery), is expected to achieve mass production, thereby driving the demand for targets.
Targets for photovoltaic thin-film batteries are mainly square plates, with purity requirements generally above 99.99% (4N), second only to semiconductor targets. At present, the more commonly used sputtering targets for preparing thin-film batteries include aluminum targets, copper targets, molybdenum targets, chromium targets, ITO targets, and AZO targets (aluminum zinc). Among them, aluminum target and copper target are used for the conductive layer film, molybdenum target and chromium target are used for the barrier layer film, and ITO target and AZO target are used for the transparent conductive layer film.
HIT batteries mainly use ITO targets as their transparent conductive films. HIT battery is to deposit amorphous silicon thin film on crystalline silicon, its structure is based on N-type single crystal silicon wafer as substrate, intrinsic amorphous silicon thin film, doped amorphous silicon thin film, metal oxide conductive layer are deposited in this order TCO, and then make positive and negative electrodes through screen printing to derive current. Related products are relatively mature, and the cost ratio is not high, about 5%.