2026-09-20T18:47:57Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/821792022-01-13T07:54:01Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023
Tomás Palacios.
Zhang, Yuhao, Ph. D. Massachusetts Institute of Technology
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science.
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
2013-11-18T17:36:25Z
2013-11-18T17:36:25Z
2013
2013
http://hdl.handle.net/1721.1/82179
861974857
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 92-98).
This thesis is divided in two parts. First, self-consistent electro-thermal simulations have been performed for single finger and multi-finger GaN-based vertical and lateral power transistors and were validated with experimental DC characteristics. The models were used to study the thermal performance of GaN-based vertical metal oxide semiconductor field-effect transistors (MOSFETs) and the lateral high electron mobility transistors (HEMTs) designed for different breakdown voltage application and at different size scaling levels. The comparison between two structures revealed that the vertical MOSFETs have the potential to achieve an up to 50% higher thermal performance, especially for higher breakdown voltage and higher size scaling level designs. Second, normally-off lateral MOS-HEMTs were developed by the combination of fluorine plasma treatment and high-temperature gate oxide deposition. Record performances have been achieved for the fluorinated MOS-HEMTs with a threshold voltage >3.5 V, a low on-resistance ~ 2 m[Omega]·cm2, a small threshold voltage hysteresis ~0.15 V, high enhancement-mode channel mobility ~ 1000 cm2V-1s-1, a breakdown voltage ~ 780 V, no current collapse and a stability with 24 h continuous on-state operation at 250 oC. In addition, an analytical model for the threshold voltage of fluorinated MOS-HEMTs was established for the first time, to enable accurate design and engineering of the threshold voltage for MOS-HEMTs. This novel technology has been demonstrated as promising to fabricate high-performance normally-off MOS-HEMTs.
by Yuhao Zhang.
S.M.
98 p.
eng
Massachusetts Institute of Technology
M.I.T. theses are protected by
copyright. They may be viewed from this source for any purpose, but
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http://dspace.mit.edu/handle/1721.1/7582
Electrical Engineering and Computer Science.
Simulation and fabrication of GaN-based vertical and lateral normally-off power transistors
Thesis
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<Abstract>This thesis is divided in two parts. First, self-consistent electro-thermal simulations have been performed for single finger and multi-finger GaN-based vertical and lateral power transistors and were validated with experimental DC characteristics. The models were used to study the thermal performance of GaN-based vertical metal oxide semiconductor field-effect transistors (MOSFETs) and the lateral high electron mobility transistors (HEMTs) designed for different breakdown voltage application and at different size scaling levels. The comparison between two structures revealed that the vertical MOSFETs have the potential to achieve an up to 50% higher thermal performance, especially for higher breakdown voltage and higher size scaling level designs. Second, normally-off lateral MOS-HEMTs were developed by the combination of fluorine plasma treatment and high-temperature gate oxide deposition. Record performances have been achieved for the fluorinated MOS-HEMTs with a threshold voltage >3.5 V, a low on-resistance ~ 2 m[Omega]·cm2, a small threshold voltage hysteresis ~0.15 V, high enhancement-mode channel mobility ~ 1000 cm2V-1s-1, a breakdown voltage ~ 780 V, no current collapse and a stability with 24 h continuous on-state operation at 250 oC. In addition, an analytical model for the threshold voltage of fluorinated MOS-HEMTs was established for the first time, to enable accurate design and engineering of the threshold voltage for MOS-HEMTs. This novel technology has been demonstrated as promising to fabricate high-performance normally-off MOS-HEMTs.</Abstract>
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