Effect of annealing on sheet carrier density of AlGaN/GaN HEMT structure

• Published in: Journal of crystal growth 2009-01, Vol.311 (3), p.859-862
• Main Authors: Chen, Nie-Chuan, Tseng, Chien-Yuan, Lin, Hsin-Tung
• Format: Article
• Language: English
• Subjects: A1. Surface structure; A3. Metal-organic chemical vapor deposition; Applied sciences; B1. Sapphire; B2. Semiconducting III–V materials; B3. Heterojunction semiconductor devices; B3. High electron mobility transistors; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2008.09.102

The effects of surface state on sheet carrier density in the Al 0.17Ga 0.83N/GaN heterostructure were investigated. The sheet carrier density obtained by Hall measurement was 1.803×10 13 e/cm 2. However, this value was inconsistent with the capacitance–voltage ( C– V) measurements. This carrier density varied with the surface conditions of the samples that were prepared for Hall and C– V measurements. To study further the effects of the surface conditions on the sheet carrier densities, the samples were annealed at various temperatures and then characterized by Hall and work function measurements. The carrier densities increased with annealing temperatures. Meanwhile, the work functions decreased. Accordingly, the relationship between the surface states and the sheet carrier densities was determined.