Temperature dependent morphology transition of GaN films
The temperature dependence of the surface morphology of GaN epilayers was studied with AFM. The layers were grown by low pressure MOCVD on (0001) sapphire substrates in the temperature range of 980--1,085 C. In this range the (0001) and {l_brace}1{bar 1}01{r_brace} faces completely determine the morphology of 1.5 {micro}m thick Ga-faced GaN films. For specimens grown at 20 mbar and temperatures below 1,035 C the {l_brace}1{bar 1}01{r_brace} faces dominate the surface, which results in matt-white layers. At higher growth temperatures the morphology is completely determined by (0001) faces, which lead to smooth and transparent samples. For growth at 50 mbar, this transition takes place between 1,000 C and 1,015 C. It is shown that the morphology of the films can be described using a parameter {alpha}{sub GaN}, which is proportional to the relative growth rates of the (0001) and the {l_brace}1{bar 1}01{r_brace} faces.
- Research Organization:
- Univ. of Nijmegen (NL)
- Sponsoring Organization:
- Dutch Technology Foundation
- OSTI ID:
- 20104733
- Country of Publication:
- United States
- Language:
- English
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