Reserarch On Deposition Process And Properties Of Silicon Nitride Thin Film Prepared By PECVD

Silicon nitride(SiNx) thin film is widely applied in the fields of integrated circuit, Micro-Electro-Mechanical System(MEMS), solar cell and display devices due to its excellent optoelectronic and mechanic properties. Due to its property of high deposition rate and the ability of flexible operation, plasma enhanced chemical vapor deposition(PECVD) has become one of the most popular method for depositing silicon nitride thin film. However, the silicon nitride film deposited by PECVD has a certain intrinsic stress, which maybe causes the device performance deterioration. Monolithic uncooled infrared focal panel array(UIFPA) device is one of typical applications of PECVD Si N x thin film, wherein the SiNx is employed as supported layer, insulator and sensitive film passivation, respectively. Consequently, it is inevitable to have an accurate knowledge about the properties, especially the thermal property of the deposited SiNx film.In this thesis, a systematic study of the influence of process parameters on PECVD film properties has been researched. Through mixed frequency(MF) plasma enhanced CVD technique, it is convenient to obtain SiNx thin film whose stress is quiet small. In addition, to obtain silicon nitride film that meet different performance requirement, one can combine different process parameters.Secondly, in this thesis we also designed a special microstructure device for thermal property test and produced it through micro-fabrication technology. During the produce process, we improved the magnetron sputtering apparatus, which makes depositing on different dimensions substrate possible. Meanwhile, these factors affect the thickness of sacrificial layer which wildly apply on lithography process have been researched accurately. It shows that the thickness of the sacrificial layer depend on spin coater’s speed and photoresist concentration. This conclusion will be instructive for actual operation work in future.Finally, in order to overcome the poor portability that process parameter ’s influence on performance of silicon nitride film limited on specific equipment, we decide to explain the influence from the micro perspective. That means we have to design vacuum chamber and plasma Langmuir probe. By inserting the Langmuir probe into plasma, one will attain curve of current. The accurate analysis will show plasma’s character parameters. Therefore, one can know how macro process affects performance of silicon nitride thin film.