Investigation of the rf and dc hollow cathode plasma-jet sputtering systems for the deposition of silicon thin films

Both rf and dc hollow cathode plasma-jet sputtering systems have been investigated for thin film semiconductor deposition. These systems were studied as a modification of the well-known rf hollow cathode plasma jet system. The aim of this modification was to provide low temperature deposition of semiconductor silicon and silicon-based alloys as thin films with these plasma jet systems. As a first step, the deposition of an already well explored, hydrogenated amorphous silicon material, a-Si:H, was chosen for experimentation. Plasma erosion of single crystal silicon nozzles in an Ar and H-2 working gas mixture was utilized for this purpose. A comparison of both dc and rf hollow cathode plasma jets has been made and correlated to the a-Si:H thin film properties. As a preliminary result, large differences between the properties of a-Si:H thin films deposited using dc and rf plasmas have been found. Monohydride Si:H composition was found for a-Si:H films fabricated using the dc plasma jet system under certain experimental conditions. However, predominantly di-hydride and multi-hydride structures and strong oxidization were found for the a-Si:H films deposited using rf plasma excitation. The sputtering efficiencies of both the rf and dc jet sources for silicon films have been found to be similar. (C) 2002 Elsevier Science B.V. All rights reserved.