Structural and morphological properties of AlGaN thin films prepared by co-sputtering technique

Abstract

AlGaN thin films can be used in a variety of electronic applications because have a wide energy band-gap and it's tuneable in range (3.11 eV-6.4 eV). However, the deposition of AlGaN facing difficulties depositing at room temperature and required longer time deposition to achieved high quality of AlGaN thin films. Due to that, there not many attempts on discovering AlGaN thin film deposition using the sputtering technique. In this work, the co-sputtering process was used to deposit AlGaN thin films, and the impacts of nitrogen gas flow rate on the structural and morphological characteristics of AlGaN thin films were examined. AlGaN films were sputtered simultaneously on silicon (111) substrate at minimum time deposition and room temperature using GaN and Al target. The fabricated AlGaN thin films were characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), and surface profilometer. The AlGaN crystal structures do not exist in the XRD result. The roughness of the AlGaN films with 50 sccm nitrogen flow was 1.19 nm, 1.41 nm for 25 sccm, and 4.91 nm for AlGaN with no nitrogen gas flow. Meanwhile, grain size readings have varied with different nitrogen gas fluxes. The profilometer shows that the thickness of AlGaN films was decreasing with the increase of nitrogen gas flow. The Co-sputtering technique may be considered a great approach to improving the deposition of AlGaN thin films at minimizing time and temperature.