The microstructures of low‐temperature polycrystalline silicon grown both on SiO2and Corning 7059 glass substrate are presented. The silicon was deposited by the hydrogen dilution method using electron‐cyclotron‐resonance chemical‐vapor deposition at 250 °C without any thermal annealing. The hydrogen dilution ratios were varied from 90% to 99%. Transmission electron microscopy images, Raman shift spectra, and x‐ray‐diffraction (XRD) patterns of the films were obtained. The maximum grain size was about 1 &mgr;m and the crystalline fraction which was characterized from Raman shift spectra was near 100%. From the XRD patterns ⟨111⟩‐ and ⟨110⟩‐oriented crystalline silicon grains were clearly present in the polycrystalline silicon films. ©1995 American Institute of Physics.