Fourier transform infrared spectroscopy characterization of AlN thin films grown on sacrificial silicon oxide layers via metal organic vapor phase epitaxy

Aluminum nitride (AlN) films were grown using metal organic vapor phase epitaxy techniques on Si (111) substrates patterned with silicon oxide (SiOx) stripes and the vibrational properties of these films were investigated by Fourier transform infrared (FTIR) techniques. The grown films contained a predominantly wurtzite AlN phase. The AlN film on SiOx was prone to corrosion when subjected to wet etching in buffered hydrofluoric acid solution thereby changing the material properties of the AlN film on SiOx. The change in the material properties of the AlN films on SiOx can be gauged from the decrease in the relative integrated areas under the A1 (TO) and E1 (TO) modes of the AlN film. The analysis shows that FTIR is a viable tool for investigating the material properties of AlN thin film structures with lateral dimensions as low as 100 μm.