Title :
In0.5(AlxGa1-x)0.5 HEMTs for high-efficiency low-voltage power amplifiers: design, fabrication, and device results
Author :
Wang, Yu-Chi ; Kuo, Jenn-Ming ; Ren, Fan ; Lothian, James R. ; Tsai, Huan-Shang ; Weiner, Joseph S. ; Kuo, Hao-chung ; Lin, Chun-hsiung ; Chen, Young-Kai ; Mayo, William E.
Author_Institution :
Lucent Technol., AT&T Bell Labs., Murray Hill, NJ, USA
fDate :
8/1/1999 12:00:00 AM
Abstract :
In0.5(AlxGa1-x)0.5 high electron-mobility transistors (HEMTs) are expected to have higher two-dimensional electron gas density and larger current drive capability than both Al0.23Ga0.77As and In0.5Ga 0.5P HEMTs due to the improved conduction-band offsets. In this paper, we performed a systematic investigation of the electrical properties of In0.5(AlxGa1-x)0.5 P (0⩽x⩽1) material system lattice matched to GaAs. By considering the conduction-band offset, direct-to-indirect-band electron transfer, donor-related deep levels, and Schottky barrier height, a relatively narrow range of the Al content 0.2⩽x⩽0.3 was found to be the optimum for the design of In0.5(AlxGa1-x)0.5 HEMTs. Under 1.2-V operation, power transistors with the optimum aluminum composition show high drain current density, high transconductance, and excellent power-added efficiency (65.2% at 850 MHz). These results demonstrate that InAlGaP HEMTs are promising candidates for high-efficiency low-voltage power applications
Keywords :
Schottky barriers; UHF field effect transistors; UHF power amplifiers; aluminium compounds; deep levels; gallium compounds; indium compounds; power HEMT; two-dimensional electron gas; 1.2 V; 65.2 percent; 850 MHz; HEMTs; In0.5(AlGa)0.5P; Schottky barrier height; conduction-band offsets; current drive capability; direct-to-indirect-band electron transfer; donor-related deep levels; high-efficiency low-voltage power amplifiers; power transistors; power-added efficiency; transconductance; two-dimensional electron gas density; Aluminum; Conducting materials; Current density; Electrons; Gallium arsenide; HEMTs; Lattices; MODFETs; Power transistors; Schottky barriers;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
