Mesa orientation dependence of lateral growth of GaN microchannel epitaxy by electric liquid-phase epitaxy using a mesa-shaped substrate

Growth of (0 0 0 1) GaN microchannel epitaxy by electric liquid phase epitaxy using a mesa-shaped substrate was optimized to enhance lateral growth by systematically changing the mesa direction. It was found that the formation of the (−1 2 −1 2) and (1 −2 1 2) facets on the sides strongly suppressed lateral growth. The area of the facets increased as the offset angle of the mesa direction from the [1 1 −2 0] axis increased. At an offset angle of 30°, lateral growth was fully suppressed by the formation of the (−1 2 −1 2) and (1 −2 1 2) facets on the whole sides. The (−1 2 −1 2) and (1 −2 1 2) planes are thought to be stable in electric liquid-phase epitaxy under our extremely Ga-rich experimental conditions. These facets formed readily on the sides when the growth front directed to [1 −2 1 0]. On the other hand, the [1 1 −2 0] mesa orientation resulted in wide lateral growth. This is because the (1 −1 0 0) facets are less stable than the (0 0 0 1) and (0 0 0 −1) planes, and do not hinder lateral growth.