Real-time monitoring and control of nitride growth rates by Metal Modulated Epitaxy

• Published in: Journal of crystal growth 2019-07, Vol.517, p.12-16
• Main Authors: Averett, Kent L., Hatch, John B., Eyink, Kurt G., Bowers, Cynthia T., Mahalingam, Krishnamurthy
• Format: Article
• Language: English
• Subjects: A1. High resolution X-ray diffraction; A3. Molecular Beam Epitaxy; A3. RHEED; B1. Nitrides; B2. Semiconducting gallium compounds; Bilayers; Epitaxial growth; Error analysis; Film growth; Gallium nitrides; Growth rate; Molecular beam epitaxy; Oscillations; Standard error; Thickness; Thin films; X-ray diffraction
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2019.04.008

•Capability to monitor growth rate of III-Nitrides, by MBE, at any point during the growth of the film or device structure.•Innovative differential analysis method which increases accuracy (reduces error) by more than 2x over previous methods.•Measurement of the Ga adlayer thickness made by RHEED Intensity analysis for the first time. The standard method for growth rate determination in semiconductor thin films, by Molecular Beam Epitaxy (MBE), is through RHEED intensity oscillations prior to device layer epitaxy. High quality III-Nitride epitaxy occurs with metal-rich surfaces and under step-flow growth conditions, which do not produce RHEED oscillations. This article demonstrates the capability to monitor the growth rate of gallium nitride (GaN), at any point during film growth with high fidelity, under step-flow growth conditions. RHEED intensity vs. time measurements determine the growth rate by Metal Modulated Epitaxy (MME). Utilizing differential analysis, a factor of 2x improvement in accuracy is demonstrated, with a Standard Error less than 4%. Complementary analysis with X-Ray Diffraction and RHEED identify the Ga bilayer thickness as 2.34 ML ± 0.08 ML, representing the first time RHEED analysis has been used to characterize the thickness of the Ga bilayer on GaN.