Aluminum Nitride Thin Films Grown by Sol-Gel Spin Coating Technique

Abstract

In this study, aluminum nitride (AlN) thin films were grown on p-type silicon (100) substrate by sol-gel spin coating method. Two types of ethanol-based precursors were prepared, namely, precursors with and without the aid of diethanolamine (DEA). The objective of this work is to investigate the effects of the DEA on the surface morphology, structural and optical properties of the deposited thin films. The coating films were undergone nitridation process under ammonia ambient at 1100 °C for 60 min. The surface morphology and structural properties of the deposited AlN thin films were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). XRD results revealed that both samples have AlN (100) preferred orientation. In addition, the crystallinity of sample without the aid of DEA is higher compared to the sample prepared with DEA. While, the AFM results showed that both samples have uniform and smooth surface. The optical properties of AlN thin films was investigated by Raman spectroscopy. For sample without DEA, Raman results showed the present of wurtzite AlN characteristics phonon modes of E2(high) and A1(LO) at 660 cm-1 and 892 cm-1, respectively. Whereas only E2(high) is observed for sample with the aid of DEA. Finally, all the results revealed that the present of DEA has a strong influence on the properties of deposited AlN thin films and film prepared without DEA have better quality.