Influence of Polarity on Surface Reaction between GaN{0001} and Hydrogen

Abstract

The influence of polarity on GaN decomposition has been investigated by an in situ gravimetric monitoring (GM) method using freestanding GaN(0001). The decomposition rate of the GaN was measured as a function of P in the temperature ranging from 800 to 950 °C. In the low-temperature region, the decomposition rate of GaN(0001) is faster than that of GaN(), where the decomposition rates of both surfaces are proportional to P3/2. On the other hand, the decomposition rate of GaN() is faster than that of GaN(0001) in the high-temperature region. In this case, the decomposition rates of both surfaces are proportional to P1/2. These results indicate that the rate-limiting reactions of GaN decomposition can be written as follows: N(surface) + 3/2H2(g) → NH3(g) at lower temperatures, and Ga(surface) + 1/2H2(g) → GaH(g) at higher temperatures.