Pyrolytic transformation from polydihydrosilane to hydrogenated amorphous silicon film

The fabrication of thin film silicon devices based on solution processes rather than on conventional vacuum processes is of substantial interest since cost reductions may result. Using a solution process, we coated substrates with polydihydrosilane solution and studied the pyrolytic transformation of the material into hydrogenated amorphous silicon (a-Si:H). From thermal gravimetry and differential thermal analysis data a significant reduction in weight of the material and a construction of SiSi bonds are concluded for the pyrolysis temperature Tp = 270 to 360 °C. The appearance of amorphous silicon phonon bands in Raman spectra for films prepared at Tp ≥ 330 °C suggests the construction of a three-dimensional amorphous silicon network. Films prepared at Tp ≥ 360 °C exhibit a hydrogen content near 10 at.% and an optical gap near 1.6 eV similar to device-grade vacuum processed a-Si:H. However, the infrared microstructure factor, the spin density, and the photosensitivity require significant improvements.

► We fabricate hydrogenated amorphous silicon (a-Si:H) films by a solution process.
► The a-Si:H films are prepared by pyrolytic transformation in polysilane solution.
► We investigate basic properties in relation to the pyrolysis temperature.
► Raman spectra, hydrogen content, and optical gap are similar to device-grade a-Si:H.
► Microstructure factor, spin density, and photoconductivity show poor quality.