Preparation And Optical Properties Of Nc-Si:H Thin Films

Using PECVD device, with H2 and SiH4 in a certain proportion of mixed gas as gas source, preparation the nc-Si:H thin films on quartz substrate; In addition, the doped nc-Si(P):H thin films were prepared on quartz as well as single crystal silicon substrate by the PH3 gas as a dopant at a certain H2 dilution ratio. The intrinsic nc-Si:H films were prepared by varying the ratio of H2 in the reactive gas; the doped nc-Si(P):H films were prepared by changing the ratio of pure PH3 and SiH4 gas flow(Cp),To analyze the effects of the changes in the concentration of the reactant gases on the microstructure and the optical properties of the thin films. Using alpha-step200 type Profilometer, Laser Raman spectrometr, Double beam UV visible spectrophotometer, DX-2500 type X-ray diffractiometer(XRD), Fourier Transform Infrared Spectrometer(FTIR) and other equipment,tested the microstructure characteristics of the prepared nc-Si:H thin films.In addition, The optical properties of the samples were analyzed by some methods. based on the nc-Si:H and nc-Si(P):H films of the transmission spectrum by a new analysis method, through the MATLAB software film transmittance formula is programmed according to, through this program data intends to merge to be analysis to obtain the prepared thin film thickness, refractive index, absorption coefficient and optical constants. Some optical constants of the samples were extracted. At the same time, The absorption coefficient and refractive index change of the sample can be obtained according to the obtained optical constants. In this process, it is required to determine the initial value of the film thickness, Envelope method is used to draw the envelope of the transmission spectrum of the thin film,and extract the interference peak value of the interference. Finally, it can be seen that the fitting of the theoretical calculation and experimental measurement of the two curves is very good, so that the method to calculate the reliability of the optical constants has been verified. This is an effective method to determine the optical constants of nc-Si:H thin films.