Process transfer of a-SixC1-x passivation layers from a laboratory - type to an industrial in-line PECVD reactor

We report the successful transfer of passivating, intrinsic a-SixC1-x,:H layers from a laboratory batch-type to an industrial in-line plasma-enhanced chemical vapour deposition (PECVD) reactor. In both cases silane (SiH4) and methane (CH4) are used as precursor gases and the plasma energy is provided by a high frequency (13.65 MHz) as well as by a microwave (2.45 GHz) generator. Intensive process parameters such as temperature (350-400 degrees C) and pressure (0.3-0.4 mbar) could be directly transferred from the lab to the industrial system whereas power and gas composition had to be adjusted carefully to the different dimensions and geometry of the in-line reactor. By means of a statistical design of the experiments a parameter range for passivating a-Si(x)Ci(1-x) layers could be found resulting in surface recombination velocities as low as S < 10 cm/s. These values could be achieved without applying any wetchemical step to the silicon samples as the cleaning of the surface was performed in-situ in the plasma chamber. The deposition rate is 100 nm/min and therefore an order of magnitude higher than in our laboratory-type system. Fourier transform infrared spectroscopy (FT-IR) measurements performed on the in-line deposited aSi SixC1-x layers reveal an elevated carbon content compared to their counterparts originating from our static laboratory PECVD reactor.