In situ control of GaN growth rate in nitrogen-limited regime

A novel approach for measuring the growth rate during GaN deposition under nitrogen-limited conditions (i.e., gallium-rich conditions) is presented. The method is based on the analysis of the variations in the optical signal measured by a pyrometer during a two-step process, the initial deposition of GaN in the Ga-rich regime and the subsequent growth of GaN through the consumption of the excess Ga under nitrogen flux. This approach provides a precise and accurate way to determine the GaN growth rate as a function of plasma generation parameters, such as nitrogen gas flux and RF power.