Effect of SiF4/SiH4/H2 Flow Rates on Film Properties of Low-Temperature Polycrystalline Silicon Films Prepared by Plasma Enhanced Chemical Vapor Deposition


IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.10   pp.1677-1684
Publication Date: 1994/10/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Semiconductor Materials and Devices
low-temperature poly-Si films,  SiF4/SiH4/H2 gas flow rates,  electrical property,  X-ray diffraction,  Raman spectra,  

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We have studied in detail the effect of gas flow rates on the film properties of low-temperature (300) polycrystalline silicon (poly-Si) films prepared by conventional plasma enhanced chemical vapor deposition (13.56 MHz) with SiF4/SiH4/H2 gases. The effect of SiH4 flow rate on crystallization is shown to be large. A small amount of SiH4 with high SiF4 and H2 flow rates (50[H2]/[SiH4]1200, 20[SiF4]/[SiH4]150, 1[H2]/[SiF4]16) is important to form poly-Si films. The poly-Si films deposited under such optimized conditions had shown preferential 〈110〉-orientation and the crystalline fraction is estimated to be more than 80%. The deposition rates are in the range of 5-30 nm/min. The conductivity is in the range of 10-8-10-6 S/cm. Further, the electrical conduction indicates an activation type, and the activation energy is in the range of 0.5-0.6 eV.