Modeling of laser reflectance evolution during metalorganic vapor phase epitaxy growth of GaN using SiN treatment

We present the simulation of laser reflectance measurements performed during GaN growth by metalorganic vapor phase epitaxy (MOVPE). We used the scattering theory approximation to determine the root mean square (rms) surface roughness versus growth time. In the region of large roughness, the determined rms roughness exceeds the maximum value authorized by the Rayleigh criterion limiting the validity of the macroscopic roughness model. Another approach based on the effective medium approximation is used to simulate the entire reflectance signal evolution. An effective refractive index and growth rate profiles are determined.