Growth and analysis of modulation-doped AlGaN/GaN heterostructure on semi-insulating SiC substrate

• Published in: Journal of crystal growth 2014-06, Vol.395, p.5-8
• Main Authors: Kim, Dong-Seok, Won, Chul-Ho, Kim, Ryun-Hwi, Lim, Byeong-Ok, Choi, Gil-Wong, Lee, Bok-Hyung, Kim, Hyoung-Joo, Hong, In-Pyo, Lee, Jung-Hee
• Format: Article
• Language: English
• Subjects: A2. Metalorganic chemical vapor deposition; Aluminum gallium nitrides; B1. 6H–SiC; B1. AlGaN/GaN heterostructure; B1. Nitrides; B3. HFET; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Density; Devices; Electron gas; Exact sciences and technology; Gallium nitrides; Heterostructures; Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Oscillations; Photoluminescence; Physics; Silicon carbide; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2014.02.046

AlGaN/GaN heterostructure was grown on semi-insulating 6H–SiC substrate. The effect of the thickness of the initial AlN buffer layer on the crystalline quality and the stress of the grown GaN layer were investigated. The semi-insulating characteristic of the undoped GaN layer, which is very important for obtaining low device leakage current, was analyzed by photoluminescence measurement. Modulation doping of Si during the growth of AlGaN barrier layer was also introduced to increase the concentration of the two-dimensional electron gas density and hence to improve the device performance. The fabricated AlGaN/GaN heterostructure field effect transistor with gate length of 0.2μm and SiO2 passiviation layer exhibited good small-signal characteristics such as current gain cut-off frequency of 47GHz and the maximum oscillation frequency of 121GHz. •The growth of modulation-doped AlGaN/GaN heterostructure on semi-insulating SiC substrate.•The investigation of the effect of HT-AlN thickness on crystalline quality and stress of GaN on SiC.•The semi-insulating characteristic of GaN layer analyzed by PL measurement.•The introduction of modulation-doped AlGaN barrier.•The fabrication of high performance AlGaN/GaN HFET with good small-signal characteristics.