Degradation study of AIGaN/GaN HEMT through electro-thermo-mechanical calculations and thermo-reflectance measurements
Name
714363478-MIT.pdf
Description
Full printable version
Size
13.94 MB
Format
Adobe PDF
Checksum (MD5)
194950924ab3743fda3413b682636046
Author(s)
Gao, Feng, Ph. D. Massachusetts Institute of Technology
Advisor(s)
Tomás Palacios.
Alternative Title
Degradation study of AIGaN/GaN high electron mobility transistors through electro-thermo-mechanical calculations and thermo-reflectance measurements
Date Issued
2010
Publisher
Massachusetts Institute of Technology
Abstract
During the last few years, AIGaN/GaN high electron mobility transistors (HEMTs) have been intensively studied for high frequency high power applications. In spite of this great interest, device reliability is still an important challenge for the wide deployment of AIGaN/GaN HEMT technology. To fully understand reliability in these devices, it is necessary to consider the electrical, mechanical and thermal properties of the operating AIGaN/GaN transistors. Since AIGaN and GaN are both piezoelectric materials, the coupling among electric field, lattice heating and mechanical characteristics gives rise to large changes in strain field and elastic energy density in the transistors under the pinch-off conditions. Most previous work have studied the inverse piezoelectric effect on device degradations, however, quantitative analysis of this failure mechanism is still needed. In this thesis, we have developed the first fully-coupled electro-thermo-mechanical simulation of AIGaN/GaN HEMTs to study the correlation between the critical voltages of the gate current degradation and the lattice temperature distributions of these devices under the reverse-gate-bias reliability testing. In addition, we have compared the numerical results of our simulations with DC measurements and high resolution thermo-reflectance images, obtaining excellent agreement for both of them. Moreover, our studies suggest a covenient and low-cost way to obtain the reliability characteristics of AIGaN/GaN HEMTs by using the thermo-reflectance measurements of the lattice temperature distributions for those devices.
Description
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 75-78).
Subjects
Materials Science and Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Terms of Use
M.I.T. theses are protected by
copyright. They may be viewed from this source for any purpose, but
reproduction or distribution in any format is prohibited without written
permission. See provided URL for inquiries about permission.
copyright. They may be viewed from this source for any purpose, but
reproduction or distribution in any format is prohibited without written
permission. See provided URL for inquiries about permission.
Persistent DSpace Link
