Laser-reflectometry monitoring of the GaN growth by MOVPE using SiN treatment: study and simulation
✍ Scribed by Fitouri, H. ;Benzarti, Z. ;Halidou, I. ;Boufaden, T. ;Jani, B. El
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 299 KB
- Volume
- 202
- Category
- Article
- ISSN
- 0031-8965
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✦ Synopsis
Abstract
The SiN treatment of the sapphire substrate for GaN growth induces a spectacular effect on the in situ reflectometry monitoring signal. Different growth modes are observed. The evolution of the reflectometry signal is simulated by the scattering theory approximation. The point‐by‐point analysis reveals that the roughness (rms) increases in the first region where the growth mode is dominated by the formation of isolated and three‐dimensional hillocks. The rms attains a maximum value exceeding that authorized by the Rayleigh criteria. Another approach based on the effective medium approximation is used to simulate the entire reflectometry signal evolution. An effective refractive index and a growth rate profile are determined. The results obtained are in accordance with the observations done by the in situ ellipsometry monitoring. We have also studied the evolution of the defined recovery time as a function of the SiH~4~ flow rate and the SiN duration. Based on the concept of a nano‐epitaxial mask, induced by the SiN treatment of the sapphire surface, we have proposed a schematic model of the GaN growth that explains the recovery‐time behavior. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)