Event
MSE Seminar - Prof. Aris Christou, University of Maryland
Friday, March 28, 2008
1:00 p.m.
Rm. 2108, Chemical and Nuclear Engineering Bldg.
Annette Mateus
301 405 5207
amateus@umd.edu
"GaN HFETs Performance and Degradation Mechanisms: Truths and Myths"
GaN-based microwave power HEMTs and power FETs are mostly grown on SiC, sapphire and Si and have defined the state-of-the art for output power density and have the potential to replace GaAs-based transistors for a number of high-power applications. Output power densities at microwave frequencies of GaN based HEMTs on both sapphire and SiC substrates have improved from 1.1 W/mm in 1992 to 9.2 W/mm at the beginning of 21st century. The GaN-based material system, consisting of GaN, AlN, InN and their alloys, has become the basis of an advanced, microwave-power-device technology for a number of reasons. GaN has a breakdown field that is estimated to be 3 MV/cm, which is ten times larger than that of GaAs (although temperature in GaN HEFTs are also very high), and a high peak electron velocity of 2.7x107cm/s. In addition, this material system is capable of supporting a heterostructure device technology with a high two-dimensional electron gas (2-DEG) carrier density and mobility. As a result of these properties, excellent high-frequency, high-power performance has been achieved with GaN-based HEMTs. Although significant progress has been made in the past few years, additional developmental work is required for GaN low-noise, high-frequency (power HEMTs) and high-power microwave (power HFETs) to become a viable technology. This presentation reviews the recent results at UMD in determining the fundamental limitations to GaN HFET performance from a defect structure point of view.
For more information, contact Annette Mateus at (301) 405-5207 or amateus@umd.edu.
