Theoretical study of improved two-dimensional electron gas density in AlGaN/GaN/AlGaN double heterostructure

✍ Scribed by Kong, Y. C. ;Chu, R. M. ;Zheng, Y. D. ;Zhou, C. H. ;Shen, B. ;Gu, S. L. ;Zhang, R. ;Han, P. ;Shi, Y. ;Jiang, R. L.

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 287 KB
• Volume: 203
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200521330

✦ Synopsis

Abstract

We evaluate the Al~x~ Ga~1–x~ N/GaN/Al~y~ Ga~1–y~ N double heterostructure (DH) for heterostructure field‐effect transistor applications, where the GaN quantum well is compressively strained on a relaxed crack‐free Al~y~ Ga~1–y~ N buffer layer, so that the Al content in the Al~x~ Ga~1–x~ N top barrier can be improved as compared with a conventional Al~x~ Ga~1–x~ N/GaN single heterostructure (SH) with the same strain in the Al~x~ Ga~1–x~ N layer. By self‐consistently solving the coupled Schrödinger and Poisson equations, we find that the two‐dimensional electron gas (2DEG) sheet density in an Al~0.6~Ga~0.4~N/GaN/Al~0.3~Ga~0.7~N DH is 2.59 × 10^13^ cm^–2^, much higher than the 1.71 × 10^13^ cm^–2^ in a conventional Al~0.3~Ga~0.7~N/GaN SH. The 2DEG sheet density increases with increasing Al content x and decreases slightly with increasing y . With a fixed Al content (x – y ) ratio, y is the key parameter determining the 2DEG density. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)