Linear thermal expansion coefficients of amorphous and microcrystalline silicon films

The linear thermal expansion coefficient, β, of hydrogenated amorphous (a-Si:H) and microcrystalline (μc-Si:H) silicon films has been investigated. The value of β of a-Si:H and μc-Si:H films was ∼1×10−6 K−1 at room temperature. It is also found that the β values for thermally annealed a-Si and polycrystalline Si were ∼4×10−6 K−1 at room temperature, coefficients similar to that of single crystalline Si. The linear thermal expansion coefficients in Si films seem to be strongly influenced by the hydrogen incorporation.