scholarly journals Integrated Optical Probing of the Thermal Dynamics of Wide Bandgap Power Electronics

Author(s):  
James Spencer Lundh ◽  
Yiwen Song ◽  
Bikram Chatterjee ◽  
Albert G. Baca ◽  
Robert J. Kaplar ◽  
...  

Abstract Researchers have been extensively studying wide-bandgap (WBG) semiconductor materials such as gallium nitride (GaN) with an aim to accomplish an improvement in size, weight, and power (SWaP) of power electronics beyond current devices based on silicon (Si). However, the increased operating power densities and reduced areal footprints of WBG device technologies result in significant levels of self-heating that can ultimately restrict device operation through performance degradation, reliability issues, and failure. Typically, self-heating in WBG devices is studied using a single measurement technique while operating the device under steady-state direct current (DC) measurement conditions. However, for switching applications, this steady-state thermal characterization may lose significance since high power dissipation occurs during fast transient switching events. Therefore, it can be useful to probe the WBG devices under transient measurement conditions in order to better understand the thermal dynamics of these systems in practical applications. In this work, the transient thermal dynamics of an AlGaN/GaN high electron mobility transistor (HEMT) were studied using thermoreflectance thermal imaging and Raman thermometry. Also, the proper use of iterative pulsed measurement schemes such as thermoreflectance thermal imaging to determine the steady-state operating temperature of devices is discussed. These studies are followed with subsequent transient thermal characterization to accurately probe the self-heating from steady-state down to sub-microsecond pulse conditions using both thermoreflectance thermal imaging and Raman thermometry with temporal resolutions down to 15 ns.

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
James Spencer Lundh ◽  
Yiwen Song ◽  
Bikramjit Chatterjee ◽  
Albert G. Baca ◽  
Robert J. Kaplar ◽  
...  

Abstract Researchers have been extensively studying wide-bandgap (WBG) semiconductor materials such as gallium nitride (GaN) with an aim to accomplish an improvement in size, weight, and power of power electronics beyond current devices based on silicon (Si). However, the increased operating power densities and reduced areal footprints of WBG device technologies result in significant levels of self-heating that can ultimately restrict device operation through performance degradation, reliability issues, and failure. Typically, self-heating in WBG devices is studied using a single measurement technique while operating the device under steady-state direct current measurement conditions. However, for switching applications, this steady-state thermal characterization may lose significance since the high power dissipation occurs during fast transient switching events. Therefore, it can be useful to probe the WBG devices under transient measurement conditions in order to better understand the thermal dynamics of these systems in practical applications. In this work, the transient thermal dynamics of an AlGaN/GaN high electron mobility transistor (HEMT) were studied using thermoreflectance thermal imaging and Raman thermometry. Also, the proper use of iterative pulsed measurement schemes such as thermoreflectance thermal imaging to determine the steady-state operating temperature of devices is discussed. These studies are followed with subsequent transient thermal characterization to accurately probe the self-heating from steady-state down to submicrosecond pulse conditions using both thermoreflectance thermal imaging and Raman thermometry with temporal resolutions down to 15 ns.


Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1599 ◽  
Author(s):  
Fabrizio Roccaforte ◽  
Giuseppe Greco ◽  
Patrick Fiorenza ◽  
Ferdinando Iucolano

Today, the introduction of wide band gap (WBG) semiconductors in power electronics has become mandatory to improve the energy efficiency of devices and modules and to reduce the overall electric power consumption in the world. Due to its excellent properties, gallium nitride (GaN) and related alloys (e.g., AlxGa1−xN) are promising semiconductors for the next generation of high-power and high-frequency devices. However, there are still several technological concerns hindering the complete exploitation of these materials. As an example, high electron mobility transistors (HEMTs) based on AlGaN/GaN heterostructures are inherently normally-on devices. However, normally-off operation is often desired in many power electronics applications. This review paper will give a brief overview on some scientific and technological aspects related to the current normally-off GaN HEMTs technology. A special focus will be put on the p-GaN gate and on the recessed gate hybrid metal insulator semiconductor high electron mobility transistor (MISHEMT), discussing the role of the metal on the p-GaN gate and of the insulator in the recessed MISHEMT region. Finally, the advantages and disadvantages in the processing and performances of the most common technological solutions for normally-off GaN transistors will be summarized.


2020 ◽  
Vol 70 (5) ◽  
pp. 511-514
Author(s):  
Subhash Chander ◽  
Partap Singh ◽  
Samuder Gupta ◽  
D. S. Rawal ◽  
Mridula Gupta

In this paper effect of self-heating has been studied of AlGaN/GaN high electron mobility transistor (HEMT) for different passivation layers which is promising device for high power at high frequencies. The different passivation layers used are aluminium oxide (Al2O3), silicon nitride (SiN) and silicon dioxide (SiO2). The device GaN HEMT has been simulated and characterised for its thermal behaviour by the distribution of lattice temperature inside the device using device simulation tool ATLAS from SILVACO. The transfer and output characteristics with and without self-heating has been studied for electrical characterisation. The channel temperature for different passivation observed is 448 K, 456 K and 471 K forAl2O3, SiN and SiO2 respectively. The observed different temperatures are due to difference in their thermal conductivity. This channel temperature information is critical to study the reliability of the device at high power levels.


2007 ◽  
Vol 4 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Kimmo Kaija ◽  
Pekka Heino

This paper is a case study of the thermal behavior of a stacked multichip package (SMCP). The aim is to measure temperature responses when heat is dissipated on different dice and to characterize the behavior with a compact thermal model (CTM) that accurately models steady-state and transient responses with a simple thermal RC -network. The measured package consists of three stacked layers, where each layer has one thinned flip chip attached die on an aramid interposer. The package's thermal responses were measured with thermal test dice that contain heaters and temperature sensors. The package was modeled with a finite element method (FEM) and the simulated temperature responses showed reasonable agreement with measured data. The FE model was further used to provide reference thermal data under different boundary conditions for CTM synthesis. The obtained CTM models accurately the steady-state and transient behavior and can be used as simplified model of the measured SMCP for further thermal analysis.


2019 ◽  
Vol 9 (17) ◽  
pp. 3610 ◽  
Author(s):  
Hwang ◽  
Jang ◽  
Kim ◽  
Lee ◽  
Lim ◽  
...  

This study investigates metal-insulator-semiconductor high electron mobility transistor DC characteristics with different gate dielectric layer compositions and thicknesses, and lattice temperature effects on gate leakage current by using a two-dimensional simulation. We first compared electrical properties, including threshold voltage, transconductance, and gate leakage current with the self-heating effect, by applying a single Si3N4 dielectric layer. We then employed different Al2O3 dielectric layer thicknesses on top of the Si3N4, and also investigated lattice temperature across a two-dimensional electron gas channel layer with various dielectric layer compositions to verify the thermal effect on gate leakage current. Gate leakage current was significantly reduced as the dielectric layer was added, and further decreased for a 15-nm thick Al2O3 on a 5-nm Si3N4 structure. Although the gate leakage current increased as Al2O3 thickness increased to 35 nm, the breakdown voltage was improved.


2008 ◽  
Vol 8 (3) ◽  
pp. 543-548 ◽  
Author(s):  
Svetlana A. Vitusevich ◽  
Andrey M. Kurakin ◽  
Norbert Klein ◽  
Mykhailo V. Petrychuk ◽  
Andrey V. Naumov ◽  
...  

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