Electrothermal Simulation of the Hot-Spot and Its Countermeasures in Cellular Bipolar Power Transistors

This paper deals with a theoretical study of the hot-spot onset (HSO) in cellular bipolar power transistors. This well-known phenomenon consists of a current crowding within few cells occurring for high power conditions, which significantly decreases the forward safe operating area (FSOA) of the dev...

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Bibliographic Details
Published inIEEE transactions on components and packaging technologies Vol. 32; no. 2; pp. 493 - 500
Main Authors Bagnoli, P.E., Stefani, F.
Format Journal Article
LanguageEnglish
Published New York IEEE 01.06.2009
The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subjects
Analytical models
Assembling
Ballasting resistors
Cellular
copper heat spreader
Devices
Electric power generation
Electrothermal effects
electrothermal modeling
hot spot
Performance analysis
power bipolar transistors
Power transistors
Proximity effect
Silicon
Simulation
Steady-state
Surface resistance
Thermal factors
Thermal resistance
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Summary:This paper deals with a theoretical study of the hot-spot onset (HSO) in cellular bipolar power transistors. This well-known phenomenon consists of a current crowding within few cells occurring for high power conditions, which significantly decreases the forward safe operating area (FSOA) of the device. The study was performed on a virtual sample by means of a fast, fully analytical electrothermal simulator operating in the steady state regime and under the condition of imposed input base current. The purpose was to study the dependence of the phenomenon on several thermal and geometrical factors and to test suitable counter measures able to impinge this phenomenon at higher biases or to completely eliminate it. The power threshold of HSO and its localization within the silicon die were observed as a function of the electrical bias conditions as for instance the collector voltage, the equivalent thermal resistance of the assembling structure underlying the silicon die, the value of the ballasting resistances purposely added in the emitter metal interconnections, and the thickness of the copper heat spreader placed on the die top just to the aim of making more uniform the temperature of the silicon surface.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:1521-3331
1557-9972
DOI:10.1109/TCAPT.2008.2001193