Effect of Substrate Alternating Current Bias on the Nanostructural Features of nc-Si:H Films

摘要

Hydrogenated nanocrystalline Si (nc-Si:H) thin films were deposited by using plasma enhanced chemical vapor deposition (PECVD); an alternating current (AC) bias with an amplitude of 60 V and a frequency range of 60 to 900 Hz was applied to the substrate electrode. The average size and concentration of the Si nanocrystallites varied from ～ 1.0 to～ 4.0 nm and up to ～ 10%, respectively, depending on the AC bias. The optical features of the films were measured in terms of the substrate bias frequency, and the PL main peak was observed to change from ～470 to ～ 710 rim. The nanostructural features of the films are discussed in terms of the variation in the energy of the positive ions penetrating the sheaths near the substrate surface with the bias frequency.