Enhanced mobility via diluted polarization in graded AlGaN/GaN systems
Abstract
This study investigates the influences of a graded AlGaN barrier layer on electron mobility in AlGaN/GaN heterostructures. By varying the graded layer thickness, we observed a systematic mobility enhancement from 1300 cm2/V s (abrupt interface) to 2070 cm2/V s at an optimal thickness of 10 nm. Beyond this threshold, mobility decreased due to the transition from two-dimensional electron gas conduction to three-dimensional parallel conduction, as confirmed by capacitance–voltage (C–V) measurements. The observed mobility enhancement is attributed to the suppression of Coulomb and alloy scattering facilitated by polarization dilution within the graded layer. Furthermore, fabricated AlGaN/graded barrier/GaN field effect transistors with a source–drain spacing of 20 μm exhibited a significant reduction in on-resistance, approximately 40% lower than conventional abrupt heterostructures. These findings highlight the potential of graded AlGaN barriers in optimizing carrier transport for next-generation high-electron-mobility transistors.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (10)
Chee-How Lu
Industry Academia Innovation School, National Yang-Ming Chiao-Tung University 1 , Hsinchu 30010,
Kazuki Kodama
Industry Academia Innovation School Wide Bandgap Compound Semiconductor Research Center, National Yang-Ming Chiao-Tung University 3 , Hsinchu 30010,
Bing-Syuan Li
International College of Semiconductor Technology, National Yang-Ming Chiao-Tung University 4 , Hsinchu 30010,
You-Chen Weng
Industry Academia Innovation School Wide Bandgap Compound Semiconductor Research Center, National Yang-Ming Chiao-Tung University 3 , Hsinchu 30010,
Chih-Yi Yang
International College of Semiconductor Technology, National Yang-Ming Chiao-Tung University 4 , Hsinchu 30010,
Yi-Qi Wang
Department of Materials Science and Engineering, National Yang-Ming Chiao-Tung University 5 , Hsinchu 30010,
Chien-Wei Chen
National Center for Instrumentation Research, National Institutes of Applied Research 2 , Hsinchu 300092,
Chan-Yuen Chang
National Center for Instrumentation Research, National Institutes of Applied Research 2 , Hsinchu 300092,
Daisuke Ueda
Industry Academia Innovation School, National Yang-Ming Chiao-Tung University 1 , Hsinchu 30010,
Edward Yi Chang