Influence of V/III Ratio of Low Temperature Grown AlN Interlayer on the Growth of GaN on Si<111> Substrate.

In this work, the influence of the V/III ratios of the low temperature (LT) AlN interlayer on GaN grown on Si<111> substrate have been investigated. It was found that V/III ratio of LT-AlN interlayer is another important growth parameter, which the crystalline quality of GaN was strongly dependent on. By optimizing the V/III ratio of LT-AlN, the high quality crack-free GaN epilayer with lower dislocation density on Si substrate have been obtained. We attribute it to the different LT-AlN surface morphology originated from optimizing the V/III ratio. Different V/III ratios could result in different GaN growth rates in vertical and lateral direction, which could effectively prevent the threading dislocation from penetrating through the LT-AlN interlayer. [ABSTRACT FROM AUTHOR]