Influence of Gas Pressure and RF Power on the Structural and Mechanical Properties of Germanium thin Films

Abstract

Germanium thin film was deposited on a glass substrate by radio frequency magnetron sputtering technique toward nanowires growth for solar cell application. Germanium thin films were deposited at room temperature. The gas pressures and radiofrequency power were varied from 50 to 100 Watt and 5 to 15 mTorr, respectively, with constant deposition time. The thickness of the deposited thin film was investigated using a high surface profilometer. Meanwhile, its structural properties were characterized using atomic force microscopy technique. Results showed that the surface roughness of the Germanium thin film decreased with the increase of gas pressure and radio frequency power. All the thin films formed were amorphous which were confirmed with X-ray diffraction analysis. The experiment results indicated that thin films deposit at 15 mTorr produced 114.76 nm of thickness and 61.9 nm of surface roughness. Meanwhile, Ge thin film deposited at 100-Watt radio frequency power had 10.2 nm of surface roughness. Therefore, growth parameters must be optimized in order to obtain the desired surface roughness which then can be used for the growth of nanowires for solar cell application.