Design and Thermal Analysis of SiGe HBT with Non-Uniform Segmented Emitter Fingers and Non-Uniform Emitter Finger Spacing

2015 ◽  
Vol 713-715 ◽  
pp. 938-941
Author(s):  
Liang Chen
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Temperature Distribution ◽  
Thermal Resistance ◽  
Three Dimensional ◽  
Heterojunction Bipolar Transistor ◽  
Junction Temperature ◽  
Ansys Software ◽  
Sige Hbt ◽  
Novel Structure

A novel multi-finger power SiGe heterojunction bipolar transistor (HBT) with non-uniform segmented emitter fingers and non-uniform emitter finger spacing was proposed to improve the thermal stability. Thermal simulation for a five-finger power SiGe HBT with novel structure was conducted with ANSYS software. Three-dimensional temperature distribution on emitter fingers was obtained. Compared with non-uniform segmented emitter fingers structure and non-uniform emitter finger spacing structure, the maximum junction temperature of novel structure reduce significantly, the thermal resistance reduce, temperature distribution were significantly improved. Thermal stability was effective enhanced.

Design and Thermal Analysis of SiGe HBT with Segmented Emitter Fingers and Non-Uniform Emitter Finger Spacing

2013 ◽  
Vol 462-463 ◽  
pp. 592-596
Author(s):  
Liang Chen ◽  
Cheng Zhong Hu ◽  
Chun Ling Jiang
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Temperature Distribution ◽  
Thermal Resistance ◽  
Three Dimensional ◽  
Heterojunction Bipolar Transistor ◽  
Junction Temperature ◽  
Ansys Software ◽  
Sige Hbt ◽  
Novel Structure

A novel multi-finger power SiGe heterojunction bipolar transistor (HBT) with segmented emitter fingers and non-uniform emitter finger spacing was proposed to improve the thermal stability. Thermal simulation for a five-finger power SiGe HBT with novel structure was conducted with ANSYS software. Three-dimensional temperature distribution on emitter fingers was obtained. Compared with traditional emitter structure, the maximum junction temperature of novel structure reduce significantly from 429.025K to 414.252K, the thermal resistance reduce from 159K/W to 141K/W, temperature distribution were significantly improved. Thermal stability was effective enhanced.

Heat Conduction and Interface Thermal Resistance in Liquid Argon Filled Silver and Graphite Nanochannels

2012 ◽  
Author(s):  
Murat Barisik ◽  
Ziyuan Shi ◽  
Ali Beskok
Keyword(s):  
Heat Conduction ◽  
Temperature Distribution ◽  
Thermal Resistance ◽  
Temperature Jump ◽  
Three Dimensional ◽  
Md Simulations ◽  
Liquid Argon ◽  
Fixed Temperature ◽  
Interface Thermal Resistance ◽  
Kapitza Length

Heat conduction between two parallel solid walls separated by liquid argon is investigated using three-dimensional molecular dynamics (MD) simulations. Liquid argon molecules confined in silver and graphite nano-channels are examined separately. Heat flux and temperature distribution within the nano-channels are calculated by maintaining a fixed temperature difference between the two solid surfaces. Temperature profiles are linear sufficiently away from the walls, and heat transfer in liquid argon obeys the Fourier law. Temperature jump due to the interface thermal resistance (i.e., Kapitza length) is characterized as a function of the wall temperature. MD results enabled development of a phenomenological model for the Kapitza length, which is utilized as the coefficient of a Navier-type temperature jump boundary condition using continuum heat conduction equation. Analytical solution of this model results in successful predictions of temperature distribution in liquid-argon confined in silver and graphite nano-channels as thin as 7 nm and 3.57 nm, respectively.

High-Temperature Transient Thermal Analysis for SiC Power Modules

2016 ◽  
Vol 858 ◽  
pp. 1078-1081 ◽  
Author(s):  
Fumiki Kato ◽  
Hiroshi Nakagawa ◽  
Hiroshi Yamaguchi ◽  
Hiroshi Sato
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
High Temperature ◽  
Thermal Resistance ◽  
Junction Temperature ◽  
Stable Operation ◽  
Transient Thermal Analysis ◽  
Die Attach ◽  
Power Modules ◽  
Transient Thermal

Transient thermal analysis is a very useful tool for thermal evaluation to realize the stable operation of SiC power modules which are operated at higher temperatures than conventional Si power modules. A transient thermal analysis system to investigate the thermal characteristics of SiC power modules at high temperature is presented. We have found that precise temperature measurement at the initial stage of the junction temperature decay curve is necessary in order to evaluate the thermal resistance and heat capacity of the die attach, since the thermal diffusivity of SiC is larger than that of Si and the temperature distribution of SiC die was considered. Using the proposed transient thermal analysis method, the thermal resistance and heat capacity of the AuGe die attach under the SiC-SBD was successfully evaluated at temperatures up to 250 °C.

Simultaneous Optimization of Ge Doping Profile and Layout in Multi-Finger Power SiGe HBTs for High Thermal Stability

2013 ◽  
Vol 816-817 ◽  
pp. 80-83
Author(s):  
R.X. Hua ◽  
D.Y. Jin ◽  
W.R. Zhang ◽  
D. Lu ◽  
Q. Fu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Temperature Distribution ◽  
Simultaneous Optimization ◽  
Doping Profile ◽  
Current Gain ◽  
Thermal Coupling ◽  
Base Region ◽  
Sige Hbt ◽  
Ge Doping ◽  
Thermal Stability Of

Considering the effect of electro-thermal feedback on the thermal stability of multi-finger power SiGe HBT, optimization of SiGe HBT on both Ge doping profile (electrical aspect) and layout (thermal aspect) is demonstrated in this paper. A novel stepped Ge doping profile of SiGe HBT with a grading Ge concentration in base region is proposed to improve the temperature coefficient of current gain, meanwhile, the cut-off frequency of HBT is also increased considerably due to the accelerated electric field caused by the Ge concentration grading. However, there is still an uneven temperature distribution. Therefore, the layout of multi-finger HBT with nun-uniform emitter finger length is optimized to compensate the thermal coupling effects and hence the uneven temperature distribution is improved obviously. It is shown that the device with simultaneous optimization of Ge doping profile and layout could be in thermal stability over a wide temperature range, which presents useful guideline to design microwave power HBTs.

Thermal Analysis of a Ceramic Package for Microelectronic Applications

1990 ◽  
Vol 112 (4) ◽  
pp. 338-344
Author(s):  
H. Rajala ◽  
M. Renksizbulut
Keyword(s):  
Thermal Analysis ◽  
Free Convection ◽  
Forced Convection ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Junction Temperature ◽  
Back Surface ◽  
Convective Conditions ◽  
Total Heat Transfer ◽  
Microelectronic Package

Thermal analysis of a ceramic microelectronic package has been performed for six configurations under prescribed free and forced convective conditions. The corresponding three-dimensional temperature fields, and thus, the complex heat flow patterns within the package have been determined. The predicted temperatures compare favorably with the experimental data obtained using a 44-lead quad package. It is observed that, in forced convection, there is no significant reduction in the junction temperatures when the package is mounted in the cavity-down configuration. In free convection, filling the cavity with helium also results in small reductions in temperatures. On the other hand, conditions existing at the back surface of the board have a fairly significant effect on the junction temperature. Although essentially negligible in the forced convection cases, thermal radiation accounts for about one-fifth of the total heat transfer from the package in the free convection cases.

Thermally-Optimum Design of GaN-on-SiC HEMT

2015 ◽  
Author(s):  
Caleb A. Holloway ◽  
Avram Bar-Cohen
Keyword(s):  
Thermal Resistance ◽  
Optimum Design ◽  
Power Amplifier ◽  
Layer Structure ◽  
Three Dimensional ◽  
Boundary Resistance ◽  
Junction Temperature ◽  
Thermal Boundary Resistance ◽  
Substrate Thickness ◽  
Design Calculations

Three-dimensional finite-element modeling is used to determine the thermally optimum design of a GaN-on-SiC MMIC power amplifier, with a focus on the parametric influence of the thermal boundary resistance (TBR), epitaxial geometry, and dissipated linear power on the HEMT junction temperature rise. A commercial MMIC power amplifier is used to set the baseline geometry and dimensions. It is found that the frequently neglected Thermal Boundary Resistance (TBR), between the GaN and SiC, not only has a significant influence on the maximum junction temperature, but directly influences the thermally-optimal GaN thickness for the HEMT transistor. The thermally-optimal GaN thickness is a balance between spreading, vertical thermal resistance, and the magnitude of the TBR. As a consequence, it is seen the commonly used, submicron l GaN thicknesses approach optimality only when the TBR values are below 10 m2-K/GW. Additionally, it is observed that increasing the gate pitch and substrate thickness helps to diffuse the flow of heat within the substrate before it proceeds into the cooling solution, resulting in an overall decrease in thermal resistance. The numerical results are used to verify the accuracy of an available analytical solution for a surface heat source on an orthotropic multi-layer structure, albeit with assumed temperature-invariant properties, thus enabling use of this relation in scoping and preliminary design calculations.

Thermal Analysis of Dedicated Computer Based on ANSYS

2011 ◽  
Vol 697-698 ◽  
pp. 277-281
Author(s):  
Y.R. Zhang ◽  
L. Gao ◽  
S.J. Li ◽  
H.X. Bi
Keyword(s):  
Thermal Analysis ◽  
Material Properties ◽  
Theoretical Basis ◽  
Three Dimensional ◽  
Test Results ◽  
Post Processing ◽  
Ansys Software ◽  
Computer Based ◽  
Three Dimensional Models ◽  
Setting Parameters

After creating the three-dimensional models of dedicated computer, models can be smoothly put into ANSYS through interface between Pro/E and ANSYS. By selecting the grid cells, setting parameters of material properties, dividing grids, applying load and boundary conditions and post-processing, the temperature contours of the whole case and its key components are got. Compared with the test results, it was verified that the feasibility and rationality of carrying out thermal simulation by ANSYS software, providing a theoretical basis for the designers to optimize dedicated computer case.

Thermo-Mechanical Analysis of Torpedo Car

2010 ◽  
Vol 44-47 ◽  
pp. 1198-1202
Author(s):  
Jing Yun Zhao ◽  
Yong Zang ◽  
Qin Qin ◽  
Di Ping Wu
Keyword(s):  
Temperature Distribution ◽  
Mechanical Behavior ◽  
Refractory Lining ◽  
Three Dimensional ◽  
Coupling Model ◽  
Mechanical Analysis ◽  
Strength Condition ◽  
Ansys Software ◽  
Local Zone ◽  
Dimensional Coupling

When a new torpedo car is developed, its thermo-mechanical stress must be analyzed carefully in order to guarantee its strength condition. This paper describes an investigation into the thermo mechanical behavior of the torpedo car using ANSYS software. A three-dimensional, coupling model of torpedo car has been established successfully. The analysis produces outputs such as the temperature distribution and coupling stress of this car. The influence of swell gap and refractory lining thinning are also discussed. The results indicate that the swell gap and entire thinning of refractory lining can reduce the stress remarkably, but the local thinning will increase the stress of this local zone.

Three Dimensional CFD Conjugate Analysis of Two Inline PLCC Packages Horizontally Mounted

2004 ◽  
Vol 1 (4) ◽  
pp. 244-260 ◽  
Author(s):  
B. Jayakumar ◽  
G. A. Quadir ◽  
M. Z. Abdullah ◽  
K. N. Seetharamu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Resistance ◽  
Transfer Coefficient ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Junction Temperature ◽  
Average Heat Transfer Coefficient ◽  
Average Heat ◽  
Air Inlet

A three dimensional conjugate analysis of heat and fluid flow of two 84-pin PLCC packages mounted horizontally on a printed circuit board in a wind tunnel is carried out using a commercial CFD code, FLUENTTM. Various inlet air velocities are used to emulate natural, mixed and forced convection conditions. Some parametric studies are carried out by varying the package chip power, gap between the packages and air inlet velocities. The results are presented in terms of the junction temperature, thermal resistance and top surface average heat transfer coefficient for each package under different operating conditions. The decrease in the junction temperature of the packages with the increase in air inlet velocity is clearly predicted. Further, the leading edge heat transfer coefficient of the packages is always higher than that at the trailing edge for all inlet air velocities considered. It is found that the variation in the package chip power does not influence the average heat transfer coefficient and the thermal resistance of the package at a particular inlet air velocity. Different correlations in terms of the junction temperature as well as the Nusselt number are presented for each package under different convection conditions.

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