Experimental Demonstration of Thermal Management of High-Power GaN Transistors with Graphene Lateral Heat Spreaders

2011 ◽  
Vol 1344 ◽  
Author(s):  
Zhong Yan ◽  
Guanxiong Liu ◽  
Javed Khan ◽  
Jie Yu ◽  
Samia Subrina ◽  
...  
Keyword(s):  
Thermal Management ◽  
High Power ◽  
Heat Dissipation ◽  
Local Temperature ◽  
Heat Spreader ◽  
Heat Spreaders ◽  
Device Structures ◽  
Graphene Flakes ◽  
Lateral Heat

ABSTRACTGraphene is a promising candidate material for thermal management of high-power electronics owing to its high intrinsic thermal conductivity. Here we report preliminary results of the proof-of-concept demonstration of graphene lateral heat spreaders. Graphene flakes were transferred on top of GaN devices through the mechanical exfoliation method. The temperature rise in the GaN device channels was monitored in-situ using micro-Raman spectroscopy. The local temperature was measured from the shift in the Raman peak positions. By comparing Raman spectra of GaN devices with and without graphene heat spreader, we demonstrated that graphene lateral heat spreaders effectively reduced the local temperature by ~ 20oC for a given dissipated power density. Numerical simulation of heat dissipation in the considered device structures gave results consistent with the experimental data.

Optimizing Diamond Heat Spreaders for Thermal Management of Hotspots for GaN Devices

2015 ◽  
Vol 2015 (1) ◽  
pp. 000336-000341
Author(s):  
Thomas Obeloer ◽  
Bruce Bolliger ◽  
Yong Han ◽  
Boon Long Lau ◽  
Gongyue Tang ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Management ◽  
Heat Dissipation ◽  
High Reliability ◽  
Experimental Tests ◽  
Heat Spreader ◽  
Thermal Compression ◽  
Common Solution ◽  
Heat Spreaders ◽  
Test Chips

As devices become smaller while still requiring high reliability in the presence of extreme power densities, new thermal management solutions are needed. Nowhere is this more evident than with the use of Gallium Nitride (GaN) transistors, where engineers struggle with the thermal barriers limiting the ability to achieve the intrinsic performance potential of GaN semiconductor devices. Emerging as a common solution to this GaN thermal management challenge are metallized diamond heat spreaders. In this paper, a diamond heat spreader has been applied with a hybrid Si micro-cooler for to cool GaN devices. Several different grades and thicknesses of microwave CVD diamond heat spreaders, as well as various bonding layers, are characterized for their thermal effects. The heat spreader is bonded through a TCB (thermal compression bonding) process to a Si thermal test chip designed to mimic the hotspots of 8 GaN units. The heat dissipation capabilities were compared through experimental tests and fluid-solid coupling simulations, both showing consistent results. In one configuration, using a diamond heat spreader 400μm thick with a thermal conductivity > 2000W/mK, to dissipate 70W heating power, the maximum chip temperature can be reduced by 40.4%, for test chips 100μm thick. And 10kW/cm2 hotspot heat flux can be dissipated while maintaining the maximum hotspot temperature under 160°C. The concentrated heat flux has been effectively reduced by the diamond heat spreader, and much better cooling capability of the Si micro-cooler has been achieved for high power GaN devices.

Fundamental Study on Thermal Characteristics of Heat Spreaders

2011 ◽  
Author(s):  
Yasushi Koito ◽  
Yusaku Nonaka ◽  
Toshio Tomimura
Keyword(s):  
Thermal Management ◽  
Theoretical Study ◽  
Thermal Characteristics ◽  
Thermal Design ◽  
Design Parameters ◽  
Heat Spreader ◽  
Fundamental Study ◽  
Discharge Characteristics ◽  
Heat Spreaders ◽  
Large Heat

A heat spreader is one of the solutions for thermal management of electronic and photonic systems. By placing the heat spreader between a small heat source and a large heat sink, the heat flux is spread from the former to the latter, resulting in a lower thermal spreading resistance between them. There are many types of heat spreaders known today having different heat transfer modes, shapes and sizes. This paper describes the theoretical study to present the fundamental data for the rational use and thermal design of heat spreaders. Two-dimensional disk-shaped mathematical model of the heat spreader is constructed, and the dimensionless numerical analysis is performed to investigate the thermal spreading characteristics of the heat spreaders. From the numerical results, the temperature distribution and the heat flow inside the heat spreaders are visualized, and then the effects of design parameters are clarified. The discussion is also made on the discharge characteristics of the heat spreaders. Moreover, a simple equation is proposed to evaluate the heat spreaders.

Near-junction heat spreaders for hot spot thermal management of high power density electronic devices

2019 ◽  
Vol 126 (16) ◽  
pp. 165113
Author(s):  
R. Soleimanzadeh ◽  
R. A. Khadar ◽  
M. Naamoun ◽  
R. van Erp ◽  
E. Matioli
Keyword(s):  
Thermal Management ◽  
Power Density ◽  
High Power ◽  
Hot Spot ◽  
Electronic Devices ◽  
High Power Density ◽  
Heat Spreaders

Copper–graphite–copper sandwich: superior heat spreader with excellent heat-dissipation ability and good weldability

RSC Advances ◽  
2016 ◽  
Vol 6 (30) ◽  
pp. 25128-25136 ◽  
Author(s):  
Bin Jiang ◽  
Huatao Wang ◽  
Guangwu Wen ◽  
Enliang Wang ◽  
Xiaoqiang Fang ◽  
...  
Keyword(s):  
Potential Application ◽  
Heat Dissipation ◽  
Thermal Conductance ◽  
Electronics Cooling ◽  
Low Density ◽  
Wearable Electronics ◽  
Heat Spreader ◽  
Heat Spreaders

Cu–graphite–Cu sandwich heat spreaders with high thermal conductance and low density present outstanding ability of heat dissipation, which have potential application in smart and wearable electronics cooling.

Thermal Management for High Power Light-Emitting Diode Street Lamp

2010 ◽  
Author(s):  
M. Ying ◽  
S. M. L. Nai ◽  
P. Shi ◽  
J. Wei ◽  
C. K. Cheng ◽  
...  
Keyword(s):  
Thermal Management ◽  
Thermal Performance ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
System Level ◽  
Light Emitting ◽  
High Power Led ◽  
Street Lamp ◽  
Lamp System

Light-emitting diode (LED) street lamp has gained its acceptance rapidly in the lighting system as one of choices for low power consumption, high reliability, dimmability, high operation hours, and good color rendering applications. However, as the LED chip temperature strongly affects the optical extraction and the reliability of the LED lamps, LED street lamp performance is heavily relied on a successful thermal management, especially when applications require LED street lamp to operate at high power and hash environment to obtain the desired brightness. As such, a well-designed thermal management, which can lower the LED chip operation temperature, becomes one of the necessities when developing LED street lamp system. The current study developed an effective heat dissipation method for the high power LED street lamp with the consideration of design for manufacturability. Different manufacturable structure designs were proposed for the high power street lamp. The thermal contact conductance between aluminum interfaces was measured in order to provide the system assembly guidelines. The module level thermal performance was also investigated with thermocouples. In addition, finite element (FE) models were established for the temperature simulation of both the module and lamp system. The coefficient of natural convection of the heat sink surface was determined by the correlation of the measurement and simulation results. The system level FE model was employed to optimize and verify the heat dissipation concepts numerically. An optimized structure design and prototype has shown that the high power LED street lamp system can meet the thermal performance requirements.

scholarly journals A Method for Thermal Performance Characterization of Ultra-Thin Vapor Chambers Cooled by Natural Convection

2015 ◽  
Author(s):  
Gaurav Patankar ◽  
Simone Mancin ◽  
Justin A. Weibel ◽  
Suresh V. Garimella ◽  
Mark A. MacDonald
Keyword(s):  
Natural Convection ◽  
Temperature Distribution ◽  
Numerical Model ◽  
Thermal Resistance ◽  
Heat Dissipation ◽  
Test Facility ◽  
Vapor Chamber ◽  
Heat Spreader ◽  
Heat Spreaders

Vapor chamber technologies offer an attractive approach for passive cooling in portable electronic devices. Due to the market trends in device power consumption and thickness, vapor chamber effectiveness must be compared with alternative heat spreading materials at ultra-thin form factors and low heat dissipation rates. A test facility is developed to experimentally characterize performance and analyze the behavior of ultra-thin vapor chambers that must reject heat to the ambient via natural convection. The evaporator-side and ambient temperatures are measured directly; the condenser-side surface temperature distribution, which has critical ergonomics implications, is measured using an infrared camera calibrated pixel-by-pixel over the field of view and operating temperature range. The high thermal resistance imposed by natural convection in the vapor chamber heat dissipation pathway requires accurate prediction of the parasitic heat losses from the test facility using a combined experimental and numerical calibration procedure. Solid Metal heat spreaders of known thermal conductivity are first tested, and the temperature distribution is reproduced using a numerical model for conduction in the heat spreader and thermal insulation by iteratively adjusting the external boundary conditions. A regression expression for the heat loss is developed as a function of measured operating conditions using the numerical model. A sample vapor chamber is tested for heat inputs below 2.5 W. Performance metrics are developed to characterize heat spreader performance in terms of the effective thermal resistance and the condenser-side temperature uniformity. The study offers a rigorous approach for testing and analysis of new vapor chamber designs, with accurate characterization of their performance relative to other heat spreaders.

Thermal Conductivity of Graphene Layers Encased in Oxide

2009 ◽  
Author(s):  
Zhen Chen ◽  
Wanyoung Jang ◽  
Wenzhong Bao ◽  
Chun Ning Lau ◽  
Chris Dames
Keyword(s):  
Thermal Conductivity ◽  
Thermal Management ◽  
Electrical Resistance ◽  
Heat Dissipation ◽  
Three Dimensional ◽  
Metal Films ◽  
Heat Spreader ◽  
Graphene Layers ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Experimental knowledge of the heat flow along graphene layers encased by oxide is essential for future graphene-based nanoelectronics, interconnects, and thermal management structures. We used a “heat spreader method” to study the heat dissipation performance of encased graphene. Fitting the experimental data with a three-dimensional finite-element method (FEM) allows the in-plane thermal conductivity of the graphene layers to be extracted. The method is validated on samples with metal films of known thermal conductivity, as determined from electrical resistance measurements and the Wiedemann-Franz law.

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