The density of defect states of AlN films deposited by radio-frequency magnetron sputtering onto <100>-oriented Si and 4H-SiC were investigated by using the deep-level-transient-spectroscopy technique. The films were grown at room temperature with varying N flows of from 4 to 20sccm and a constant Ar flow of 10sccm. In general, the defect densities of AlN were lower when grown on 4H-SiC substrates than on Si substrates. The observed defect levels were identified as being a donor-like triplet of N vacancy and DX-like centres. Defects located at 0.35 to 0.42eV below the conduction band, attributed to dangling bonds of N atoms, were seen in samples grown using higher N flow rates. Shallow-level defects, observed at approximately 0.1eV below the conduction band, could be attributed to the recently discovered prismatic stacking fault in the AlN atomic structure.

Density of Defect States of Aluminum Nitride Grown on Silicon and Silicon Carbide Substrates at Room Temperature. V.Ligatchev, Rusli, Z.Pan: Applied Physics Letters, 2005, 87[24], 242903 (3pp)