Evolution of structure in thin microcrystalline silicon films grown by electron-cyclotron resonance chemical vapor deposition

Abstract

The growth of microcrystalline silicon, μc-Si, films has been studied by infrared spectroscopy and x-ray diffraction. Thin films of various thickness have been prepared from SiH4–H2 mixtures by electron-cyclotron resonance chemical vapor deposition. Two structural transitions were observed during film growth. The first transition at a critical thickness of dac=9 nm manifested itself by a change from an initially amorphous growth to polycrystalline growth. The second structural transition was related to an increasing amount of silicon grains of preferred orientation with (110) lattice planes parallel to the substrate. The population of such (110)-oriented grains N110 was found to become dominant at about d110=310 nm, which may be considered as a second critical thickness above which the film exhibits a (110) fiber texture. The increase of N110 with increasing thickness follows a d1/6 dependence. The effect is understood in terms of an interplay between etching and deposition during growth.

Raman spectroscopy of heavily doped polycrystalline and microcrystalline silicon

“…It is well known from the literature that the microstructure of undoped microcrystalline silicon changes considerably with the film thickness (e.g. [17]). Thus there are two possible origins to a change of the Raman spectrum in case of a different Raman laser wavelength which are very difficult to separate.…”

New approaches for the production of nano‐, micro‐, and polycrystalline silicon thin films

“…Such inhomogeneous structure for µc-Si:H films deposited by hydrogen dilution has been revealed by various techniques: spectroscopic ellipsometry [52], Raman spectroscopy [50,53], and atomic force microscopy [54], and its origin related to growth of the film. Figure 6 summarizes our studies on the effect of ions on µc-Si:H deposition.…”

A pulsed EDMR study of hydrogenated microcrystalline silicon at low temperatures

“…For the coherent amplification of the microwave radiation, a 1kW travelling wave tube amplifier was used, yielding microwave field strengths in the lower mT range. The sample is a 2.7µm thick film of hydrogenated microcrystalline silicon, deposited on 1737 Corning glass by electron-cyclotron resonance chemical vapor deposition as outlined elsewhere [20]. It was contacted with 48 interdigited aluminium grids of 300nm thickness, 30µm width and 50µm distance.…”