Research On Preparation Of Multi-layer Nitride Silicon Antireflective Film By PEVUD

Silicon nitride coatings have been widely used in the field of semiconductor device, Microelectronic industry, and solar cell because of its advantageous chemical stability, insulativity and optical properties. Recently, Silicon nitride film used as passivation antireflective film of silicon solar cells has been increasingly concerned. In the pioneer studies on silicon solar cells, the solar cell surface passivation and antireflection are always the key subjects. For the purpose of improving short circuit current, open circuit voltage and photoelectric convertion efficiency,the solar cell positive emitter requires surface antireflection film with not only excellent anti-reflection effect,but also good passivation effect.In this study, silicon nitride antireflection coatings were deposited on the surface of polycrystalline silicon by the method of plasma chemical vapor deposition (PECVD). This study mainly focuses on the principle and thenique of silicon nitide antireflection in the application of polycrystalline silicon solar cell with the structure of N+/P/P+. The antireflection and passication effects of single-layer silicon nitride antireflection coating and double-layer silicon nitride coatings deposited on polycrystalline silicon surface were compared and analysed by using Sentech ellipsometry (SE400adv), Samilab minority carrier lifetime tester (WA-200), IPCE tester (Solar Cell Scan100) and3i System halm solar cell testing and sorting machine. The results indicate that double-layer silicon nitride coatings have the advantage of improving polycrystalline minority carrier lifetime effectively, reducing polycrystalline surface reflectivity, with which the electrical properties of solar cell can be enhanced remarkably. Subsequently, the film thickness, refractivity, deposition rate, HF corotion rate and electrical properties of double-layer silicon nitride coatings were studied with the aim of understanding the influence of technique parameters on the performance of double-layer silicon nitride antireflection coatings. According to the results, it can be concluted that the parameters including substrate temperature, redio frequency, radio-frequency power and chamber pressure have most impact on the antireflection coatings, based on which, the silicon nitride antireflection coating preperation technique can be optimized and improved. In the last, the exploratory research programme about how to deposite composite antireflective coatings with multi-structure on polycrystalline silicon surface was proposed as certain referrence to future research on materials and multi-structure composite coatings.