Browsing by Author "Chou, Hsin-Ping"

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Development and characterization of the thermal behavior of packaged cascode GaN HEMTs
(2016-01-01)
Chou, Hsin-Ping
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Cheng, Stone
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Cheng, Chia-Hsiang
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Chuang, Chia-Wei
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機械工程學系
This study investigates the heat generation behavior of packaged normally-on multi-finger AlGaN/GaN high electron mobility transistors (HEMTs) that are cascoded with a low-voltage MOSFET (LVMOS) and a SiC Schottky barrier diode (SBD). By foremost carrying out electro-thermal simulation and related thermal measurements with infrared thermography and Raman spectroscopy for basic 5 mm GaN HEMTs, the location of hot spot in operating device can be obtained. Based on the outcome, further packaged cascode GaN HEMT is analyzed. A hybrid integration of the GaN-HEMT, LVMOS, and SiC SBD are assembled on a directly bonded copper (DBC) substrate in the four-pin metal case TO-257 package. The metal plate is used as both the source terminal and heat sink. The analytical results of thermal investigation are confirmed by comparing them with the infrared thermographic measurements and numerical results obtained from a simulation using Ansys Icepak. For a power dissipation of less than 11.8 W, the peak temperature of the GaN HEMTs is 118.7 degrees C, obtained from thermal measurements. (C) 2015 Elsevier Ltd. All rights reserved.
In Depth Thermal Analysis of Packaged GaN on Si Power Devices
(2013)
Wang, Chieh-An
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Chou, Hsin-Ping
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Cheng, Stone
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Chou, Po-Chien
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機械工程學系
AlGaN/GaN high electron mobility transistors (HEMTs) are one of the prospective candidates for high switching frequency power electronics applications thanks to its wide band gap (3.4eV), high breakdown voltage, large critical electric field, high carrier mobility, and the inherent high speed characteristics. With the high power densities that AlGaN/GaN HEMTs are capable of reaching, heat dissipation is a crucial issue. This paper presents the thermal analysis of packaging development, the device is attached on a V-groove copper base, and mounted on TO-3P leadframe to enhance Si substrate thermal dissipation. The effects of structure design and fabrication processes on the device performance as well as thermal resistance were studied. In addition, micro-Raman/Infrared (IR) thermography was used to investigate temperature profiles and hot spot of the devices. Simulations provide key insights into device operation and the thermal mechanisms that affect reliability. After incorporating self-heating effect in calculations of current-voltage characteristics, our results agreed well with experimental data.
Thermal Analysis and Electrical Performance of Packaged AlGaN/GaN Power HEMTs
(2013)
Chou, Po-Chien
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Cheng, Stone
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Chieng, Wei-Hua
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Chang, E. Y.
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Chou, Hsin-Ping
This work presents thermal resistance constitution evaluation and electrical experiments for AlGaN/GaN HEMTs packaging device. The investigation of thermal resistance is based on the closed-form expression heat transfer model. Actual multi-fingers structure and thermal resistance was modeled. The Infrared thermography is utilized to observe heat distribution of the packaged GaN device by measuring the temperature of the active region in the operation. The simulation result is verified by comparing with experimental observations. The total thermal resistance is 134.42 K/W by calculation while that is 145.77 K/W by simulation. The self-heating effect under switching operation is verified by IR image. The simulation process is calibrated against measurement data of a actual device and provides good predictive results for the DC characteristics.
Thermal performance evaluation of cascode Paralleled-GaN-HEMTs packaging for high power switching applications
(2017-01-01)
Chou, Hsin-Ping
;
Cheng, Stone
;
機械工程學系
;
Department of Mechanical Engineering
This study investigated the heat generation behavior of normally-on GaN FET consisting of multi-chip AlGaN/GaN high electron mobility transistors (HEMTs) cascoded with a low-voltage MOSFET (LVMOS) and a SiC Schottky barrier diode (SBD) in a new design package to enable high power applications. The electric field intensity distribution and the hot spot position of the devices were analyzed by electrothermal simulation and the infrared temperature measurement. The transient thermal characteristics are probed by temperature sensitive parameters (TSPs). The changes in on-resistance (R-ON), maximum drain current (IDMAX), and transconductance (g(m)) with temperature from 25 degrees C to 150 degrees C are measured, and the correlations are investigated. Two paralleled GaN-HEMT, LVMOS, and SiC SBD were then integrated on a directly bonded copper (DBC) substrate in the four-pin metal case TO-257 and a newly designed REC-2015 package to evaluate steady thermal performance improvement of packaging. The temperature distribution of parallel-connected GaN HEMTs were analyzed in numerical thermal simulations and infrared thermography measurements. The analytical results of thermal analysis were confirmed by comparing with the infrared thermographic measurements and numerical results obtained from simulations using Ansys Icepak. According to the thermal measurement at power dissipation of less than 24 W, the peak temperatures of the GaN HEMTs are 144.7 degrees C and 132.6 degrees C with TO-257 and REC-2015 package.