Influence of the low-temperature AlN interlayers on the electrical properties of AlGaN/GaN heterostructure on Si substrate

In this work, the electrical properties of AlGaN/GaN heterostructure grown on Si substrate with low-temperature AlN (LT-AlN) interlayers were investigated. Hall effect measurement was used to test the electrical properties of AlGaN/GaN heterostructure in all samples with different LT-AlN thickness. It is showed that the thickness of low-temperature AlN interlayers in the bufferlayer obviously effect the electrical properties of two-dimensional electron gas (2DEG) in the heterostructure channel. The sample with 15 nm LT-AlN interlayers reached the maximum electron mobility of 4090 cm2/Vs. Combined with XRD and AFM measurements, it is found that the dislocation density, surface roughness and stress conditions determined the electrical properties of 2DEG.