Study On The Properties Of Microcrystalline Silicon Thin Films Prepared By Hot-wire Chemical Vapor Deposition

In this paper, the microcrystalline silicon (μc-Si) thin films prepared by hot-wire chemical vapor deposition (HWCVD) have been characterized and analyzed by X-ray diffraction (XRD), transmittance spectroscopy, scanning electron microscope (SEM), hall effect, volt-ampere characteristics curve, and impedance spectra. According to the result of analysis, the effects of gas pressure on optical band gap, the effects of the annealed conditions on grain size, the effects of the impurity concentration on the electrical properties, and the effects of the intrinsic thin layer thickness on semiconductor characterization have been discussed respectively as follow:1. The values of optical band gap decrease with increasing gas pressure. It is because of the different collision rate of motifs in different gas pressure. The higher gas pressure, the bigger collision rate, and then it bring on the different gas reactions respectively.2. The relation between the grain size ofμc-Si thin films and the annealed conditions is: the values of grain size increase with increasing annealed temperature; the thin films with the shorter annealed time have the larger grain size. It is because of the films thickness and grain density.3. The values of carrier mobility decrease with increasing the impurity concentration. The effects of many factors on carrier mobility of thin films have been discussed. Then we found that the values of carrier mobility increase with increasing grain size.4. After analyzing the volt-ampere characteristics curve and impedance spectra of thin films, we discuss the effects of the intrinsic thin layer thickness on HIT structure and electrical properties. We found that values of equivalent resistance increase with increasing the thickness of intrinsic thin layer.