Tft Gate Insulating Layer Of Silicon Nitride Film

Silicon nitride thin film is a kind of very important electric dielectrics with excellent optoelectronic, insulator, mechanical and passivation properties. It will be widely used in optoelectronics, microelectronics and so on. Silicon nitride thin film is mainly used for inner insulator film, the gate insulator layer of field effect transistor (or thin film transistor), the charge storage layer of random memory, sensitivity film, passivation layer, ion stopped layer and encapsulation materials etc. Because plasma enhanced chemical vapor deposition (PECVD) succeeded in depositing excellent thin film under lower temperature (<700K), PECVD has been one of the most important methods to prepare silicon nitride thin film in industry. Because the reaction mechanism of PECVD is very intricate and the reaction is beyond control, the standard chemical metric Si3N4 is not obtained. Lots of experiments indicate that the form, structure and properties of silicon nitride thin film prepared by PECVD are related to deposition parameters. At the same time, the results from different systems are usually different and even opposite. The work done previously is experiential. To this day, the researches on silicon nitride thin film prepared by PECVD stay initial stages, so it is necessary to further develop PECVD. On the other hand, it is essential to prepare high quality silicon nitride thin film for gate insulator layer of TFT in order to get excellent TFT. In the process of silicon nitride thin film prepared by PECVD, deposition parameters strongly influence the properties of silicon nitride thin film. The key deposition parameters are substrate temperature, radio frequency power, reactant gas ration and reaction pressure. The other parameters such as background vacuum, radio frequency also have an effect on its properties in some degree. The motive of this paper is to investigate the relationship between deposition parameters and its properties in order to prepare excellent silicon nitride silicon thin film for gate insulator of TFT. In experiment, a series of silicon nitride thin films are prepared on cleaned silicon wafer by varying deposition parameters. The samples under different conditions are studied by current-voltage measurement and capacitance-voltage measurement. By analyzing the observation and data, the influence of deposition parameters on the electrical properties and interface characteristics of silicon nitride...