Electrical characteristics of atomic layer deposited AIN on n-InP

摘要

Atomic layer deposited AlN films on n-InP were electrically characterized. Compared to the sample without AlN, the interface state density obtained from the capacitance-voltage (C-V) measurements was found to decrease with a 7.4 nm thick AlN. According to X-ray photoelectron spectroscopy (XPS) measurements, the sample with a 0.7 nm thick AlN showed dominant peaks related with oxygen bonds (Al-O and In-O). For the sample with a 7.4 nm thick AlN, the dominant peak near the AlN/InP interface was associated with Al-O and N-In bonds whereas it was associated with Al-N bonds near the AlN surface. In addition, the strong emission peaks associated with Al-O bonds were observed across the AlN layer, which indicates that some part of AlN layer is composed of Al-O bonds (like Al2O3). The reverse leakage current for the sample with a 7.4 nm thick AlN at high electric field was explained by Poole-Frenkel (PF) emission, connected with nitrogen vacancy (V-N) and oxygen substituting for nitrogen (O-N) in the AlN layer.