Formation of microcrystalline silicon at low temperatures and role of hydrogen

Changes in the growth of thin silicon films at very low substrate temperatures (35 °C < T _S < 100 °C) near the a-Si:H/μc-Si:H transition region are illustrated using RMS roughness, crystallinity and hydrogen content measurements together with the corresponding evolution of the optoelectronic properties: dark conductivity σ _D , its activation energy E _a and prefactor σ ₀ as well as the ambipolar diffusion length L _diff. The role of hydrogen content, which increases at lower T _S, is studied in relation to grain boundary formation.