Understanding of surface pit formation mechanism of GaN grown in MOCVD based on local thermodynamic equilibrium assumption

Gao Zhi-Yuan^†,, Xue Xiao-Wei, Li Jiang-Jiang, Wang Xun, Xing Yan-Hui, Cui Bi-Feng, Zou De-Shu

High-magnification HRSEM images of c-plane GaN surface showing the bilayer coverage of Ga droplets. (a) Sample G, grown under a V/III atom ratio of 1940 and temperature of 915 °C, the Ga droplets are significant and scattered; (b) Sample B, grown under a V/III atom ratio of 2945 and temperature of 915 °C, the aggregation of the Ga droplets is not significant; (c) Sample C, grown under a V/III atom ratio of 2945 and temperature of 865 °C, the Ga droplets are smaller and tighter than those in Sample C.