Effect of Si, Mg, and Mg-Zn doping on structural properties of a GaN layergrown by metalorganic chemical vapor deposition

We have studied the structural properties of undoped, Si-doped, Mg-doped, a nd Mg-Zn codoped GaN using high-resolution X-ray diffraction (HRXRD) and tr ansmission electron microscopy. When compared with undoped GaN, the disloca tion density at the surface of the GaN layer decreases with Si doping and i ncreases with Mg doping. In addition, we observed a reduction of dislocatio n density by codoping with Zn atoms in the Mg-doped GaN layer. The full wid th at half maximum of HRXRD shows that Si doping and Mg-Zn codoping improve the structural quality of the GaN layer as compared with undoped and Mg-do ped GaN, respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.