Fabrication of Microcrystalline Silicon Thin Film by Ionized Physical Vapor Deposition Process

The present manuscript describes the fabrication of microcrystalline silicon (µc-Si) thin films at room temperature using the ionized physical vapor deposition (iPVD) process. The iPVD chamber incorporates a planar DC magnetron and an additional RF coil to generate an intermediate dense plasma region between the target and the substrate. The intermediate dense plasma enhances the ionization of sputtered neutral Si atoms before deposition in the iPVD process. This process greatly impacts the structural, morphological, and optical characteristics of the Si thin films. X-ray diffraction (XRD) reveals that conventional PVD produces an amorphous Si thin film, while iPVD yields a µc-Si thin film with peaks at 28.5° and 47.3°, corresponding to the (111) and (220) planes of Si. Raman spectroscopy confirms the microcrystalline nature of the Si thin film, showing approximately 70% crystallinity in the iPVD process. FESEM images display a granular structure for PVD and a cauliflower-like structure for the iPVD process. AFM images indicate a significant reduction in surface roughness for iPVD films compared to the PVD process. UV-Visible absorption spectroscopy shows that the optical band gap (Eg) decreases from (1.7 ± 0.08) eV to (1.4 ± 0.05) eV while shifting from the PVD to iPVD process.