Structural analysis of polycrystalline silicon thin films produced by two different ICPCVD approaches

Abstract

The structural properties of polycrystalline Si (poly-Si) thin films formed by using ICPCVD and LIA-ICPCVD methods under different H dilution ratios were investigated. Columnar-structured poly-Si films with 82% crystalline volume fraction were obtained by ICPCVD at a lower H dilution ratio of 50%. In the case of LIA-ICPCVD, to obtain nearly the same crystalline volume fraction (80%), a higher H dilution ratio (98%) was required and the poly-Si films obtained were mostly of cone-shaped columnar structure. The reverse effect is due to the difference in the antenna design in these systems, which changes the plasma characteristics. Multilayer deposition process, and subsequent H treatment and annealing were used in ICPCVD for producing highly crystallized poly-Si thin films from microcrystalline Si films. In the case of LIA-ICPCVD, annealing the ITO coated glass substrate in the deposition chamber prior to Si:H film deposition together with the optimization of process pressure yielded highly crystalline poly-Si film.