Technological solution for the automatic replacement of the catalytic filaments in HWCVD

• A technological solution is proposed for the automatic filament replacement in a HWCVD apparatus where silane is used as precursor gas.
• A protection mechanism has been developed to protect the filament cold ends during silane decomposition.
• Validaton tests proved the effectiveness of the new HWCVD apparatus to guarantee the reproducibility and stability of the catalytic filament conditions in a HWCVD process.

The degradation of the catalytic filaments is the main factor limiting the industrial implementation of the hot wire chemical vapor deposition (HWCVD) technique. Up to now, no solution has been found to protect the catalytic filaments used in HWCVD without compromising their catalytic activity. Probably, the definitive solution relies on the automatic replacement of the catalytic filaments. In this work, the results of the validation tests of a new apparatus for the automatic replacement of the catalytic filaments are reported. The functionalities of the different parts have been validated using a 0.2 mm diameter tungsten filament under μc-Si:H deposition conditions.