ArF laser CVD of hydrogenated amorphous silicon: The role of buffer gases
| Autor: | Stefano Chiussi, T. R. Dietrich, F. J. Comes, H. Stafast |
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| Předmět: |
Amorphous silicon
Materials science Physics and Astronomy (miscellaneous) Band gap business.industry Buffer gas General Engineering Analytical chemistry General Chemistry Activation energy Substrate (electronics) Amorphous solid chemistry.chemical_compound Semiconductor chemistry General Materials Science Disilane business |
| Zdroj: | Scopus-Elsevier |
| Popis: | ArF laser-induced CVD has been employed to generate hydrogenated amorphous silicon (a-Si:H) from Si2H6 gas dilute with He, Ar, or H2. The formation of amorphous films or powder is found to depend critically on the kind of buffer gas, the stationary total and partial gas pressures, and the substrate temperature. These dependences have been investigated in the 1–5 Torr pressure and 100–400 °C temperature ranges. They are semiquantitatively discussed in terms of ArF laser photolysis of disilane, gas heating by heat flow from the substrate and laser irradiation, diffusion, and gas phase polymerization. Furthermore, photo ionization has been observed but found irrelevant for the a-Si:H layer properties. The photo and dark conductivities (σph,σd) of the semiconductor layers are determined by the substrate temperature. Theσph values range between 10−7 and 10−4 Ω−1 cm−1 and theσd values between 10−11 and 10−8 Ω−1 cm−1. The maximum ratioσph/σd amounts to 4×104. The layers are further characterized by their optical band gap and activation energy. The layer properties are compared to literature values of amorphous films prepared by various photo, HOMO, and plasma CVD methods. |
| Databáze: | OpenAIRE |
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