High Performance AlGaN HEMT Devices Grown on Lattice Matched Substrates

"AlGaN-based heterostructures have demonstrated versatility in optical and electronic applications which is practically unmatched by other material systems. The AlGaN/GaN high electron mobility transistors (HEMTs) constitute a leading candidate forsimultaneously realizing ultra-high frequency low noise amplifiers and power amplifiers. The electron transport properties at the AlGaN/GaN interface along with the high electron saturation velocity and high breakdown fields in GaN are the basis for thesuperior performance of these devices. AlGaN/GaN HEMTs on SiC, 100 - 150 mm-wide with a record power density of 9.8 W/mm at 8 GHz (about ten times GaAs devices) have been demonstrated with gain of 9.6 dB and power added efficiency of 47%. While thesedevices and amplifiers were grown using metal-organic chemical vapor deposition, recently AlGaN/GaN HEMTs grown by molecular beam epitaxy (MBE) have essentially attained parity. We will study the design, development, and fabrication of HEMT devices usingMBE. In the last decade, electronic devices that operate reliably at high temperatures in excess of 300 C and beyond have been under development for a wide variety of new applications.The GaN/AlGaN-based HEMT power transistors have wide commercial markets in radar and range finding, collision avoidance, digital transmission (including HDTV, MMDS and LMDS), satellites, and automobiles and engine sensors. The high temperature and highsingle transist