A-si Tft With Silicon Nitride Films And Their Performance

The hydrogenated amorphous silicon nitride (a-SiN_x:H) thin films silicon nitride thin film has excellent physical and optical properties, and is widely used in optoelectronics, microelectronics, solar cell and so on, especially for the rapid development of the thin film transistor of TFT-LCD in the past 10 years. In experiments, the thin films were produced in a radio-frequency Plasma-Enhance Chemical Vapor Deposition (rf-PECVD) system using NH₃/SiH₄/N₂ mixture source gases on 1.3m×1.1m glass substrate.The silicon nitride thin film has three main applications as an important material for the thin film transisitor: 1) it has excellent insulator performance, highbreakdown field strength, low electronic defect density as the gate insulator layer and so on; 2) as the passivation layer, it has high dielectronie constant, strong resist alkali ions(such as Na⁺), low pinhole defect density and so on; 3) as the interface layer, it not only has good insulator performance, but also has lower electronic defect density than gate insulator layer, the more important effect is to reduce the interface states between the a-Si:H and the gate dielectric, and enhance the on conductance and stability of thin film transistors(TFTs).Because the reaction mechanism of RF-PECVD is very intricate, lots of experiments indicate that the fabrication, configuration and properties of silicon nitride thin film prepared by RF-PECVD are related to processing parameters. The work done previously is experiential. To this day, the researches on silicon nitride thin film still stay initial stages, so it is necessary to future researches on silicon nitride thin films. In this study, the purpose of experiments is to prepare excellent silicon nitride thin film which is a suitable material for industrial production, and determine the structural properties of a-SiN_x:H thin films with Fourier Transform Infrared (FTIR) measurement and relate these to both the processing parameters and their physical/optical properties.Fourier Transform Infrared measurement is one of the most important methods to research the fabrication and configuration of silicon nitride thin film. The intensities of spectra peaks are dependent linearly on the density of absorbing species, The HSiN₂Si/ H₂SiNSi, H₂SiN₂ and HSiN₃ absorbing species have contributed to the Si-H absorption peak. The research indicates that the Si-H bond density could be obtained by calculating the intensities of Gauss standard normal curves which is essential for fitting the FTIR spectrum properly.Spectroscopic ellipsometry and spectroscopic reflectometry are important methods to research the physical and optical properties of silicon nitride thin film. The main processing parameters are plasma power, chamber pressure, electrode spacing, substrate temperature, gases flow and so on. The motive of this paper is to investigate the effect of processing parameters on the properties of silicon nitride and the coverage performance of insulator layer, and the effect of the film thickness of interface layer on the conduction current performance of thin film transistor.