Modeling of self-heating in GaAs/AlGaAs HBTs for accurate circuit and device analysis

Baureis, P.; Seitzer, D.; Schaper, U.

doi:10.1109/gaas.1991.172650

Cited by 16 publications

(5 citation statements)

References 4 publications

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“…The transit time of the HBT is dominated by the base transit time and the transit time forthe collector depletion region. The base transit time is given by [12]: (4) whereas the transit time through the base collector depetion width WCB can be written as: where rE is the sum of the emitter layer resistance RE and the differential emitter resistance. The charge continuity is guaranteed by the appropriate mirror charge on the opposke side of the junction for each charge.…”

Section: The Modelmentioning

confidence: 99%

“…distance) as input parameters. Including an equation for the power balance of the HBT it will be shown that the one dimensional set of equations gives a good representation of the self-heating effect in the dc range [4] as well as the behavior of the junction temperature under large signal conditons [5]. The model core is embedded in an equivalent circuit of passive elements representing the extrinsic regions of the HBT.…”

Section: Introductionmentioning

confidence: 99%

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Physical heterojunction bipolar transistor model for microwave large signal simulation

Schaper

Ahlers

1995

25th European Microwave Conference, 1995

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A new physical large signal HBT model is proposed in this contribution. To our knowledge it is the first time that a physical large signal HBT model is implemented into a circuit simulator. The new HBT model descrbes the transistor action of the intrinsic HBT by an analytic formulation based on physical prnciples. The core of this model comprises emitter, base and oollector layers, the corresponding model parameters are given by material and design data. It is shown that a one dimensional description of the core including an equation for the power balance of the transistor is sufficient to descrbe the self-heating effect in the dc range as well as the junction temperature under large signal conditions. The extrinsic regions of the HBT are modelled by an equivalent circuit with passive elements. The values for these parasitic elements are given by material data and by an extraction method based on measured characterstics.

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Section: The Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Physical heterojunction bipolar transistor model for microwave large signal simulation

Schaper

Ahlers

1995

25th European Microwave Conference, 1995

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“…The self-heating effect is recognized as one of the major factor limiting the performance of heterojunction bipolar transistors (HBTs) [1][2][3][4][5][6][7][8][9][10][11][12][13]. In multifinger devices when a critical temperature is reached, the equal current distribution over the fingers can be unstable against a small temperature fluctuation and the current flow over the fingers can become inhomogeneous.…”

Section: Introductionmentioning

confidence: 99%

“…The effect manifests itself as a decrease in the collector current causing a drop in current gain, hence the "gain collapse" effect. Electrical experiments and thermal analysis have been performed under the DC or transient conditions [1][2][3][4]7]. Thermal observations from the device top side under the DC conditions have been performed by infrared (black-body) thermometry [1].…”

mentioning

confidence: 99%

Current gain collapse in HBTs analysed by transient interferometric mapping method

Bychikhin

Dubec

Kuzmı́k

et al. 2007

2007 European Microwave Integrated Circuit Conference

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Thermal distribution during a current gain collapse event is investigated in multi-finger InGaP/GaAs HBTs using the transient interferometric mapping method. The onset of the collapse is observed at time of about 1ms in devices with a low emitter ballasting resistance R E , while for HBTs with a high R E , the current is distributed equally over the fingers. 3D thermal simulation supports the results and allows an estimation of temperature at which the collapse occurs. I. INTRODUCTIONThe self-heating effect is recognized as one of the major factor limiting the performance of heterojunction bipolar transistors (HBTs) [1][2][3][4][5][6][7][8][9][10][11][12][13]. In multifinger devices when a critical temperature is reached, the equal current distribution over the fingers can be unstable against a small temperature fluctuation and the current flow over the fingers can become inhomogeneous. The hottest fingers carry the most of the current (current crunching) inducing a positive feedback effect, which may be dangerous. The effect manifests itself as a decrease in the collector current causing a drop in current gain, hence the "gain collapse" effect. Electrical experiments and thermal analysis have been performed under the DC or transient conditions [1][2][3][4]7]. Thermal observations from the device top side under the DC conditions have been performed by infrared (black-body) thermometry [1]. However there is a lack of data of direct observation of the phenomenon under the transient conditions. On the other hand, it has been found that the proper increase in the emitter ballasting resistance [12] and optimization of thermal design [11] can decrease the HBT susceptibility to gain collapse, by keeping acceptable performances.In this paper we use the transient interferometric mapping (TIM) method [14] for the thermal imaging of multifinger InGaP/GaAs HBTs prior and at the onset of the gain collapse. Devices with a high and low R E are investigated.

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“…This is kiiown to cause degradation of the device characteristics such .a gain and tan induce thermal runaway. Technological solutions that pi ovide thermally stable HB'I"s have been presented recenily [l], [2], [3] 111-corporation of self-beating effects in HBT large-sigEal models has also been reported in the past [4], 151, [6 , [7]. Physically baaed SPICE-compatible HBT large-signal rnodels have, finalii, been presented recently [<I, [9].…”

Section: Introductionmentioning

confidence: 98%

A heterojunction bipolar transistor large-signal model for high power microwave applications

Samelis

Pavlidis

Proceedings of 1995 IEEE MTT-S International Microwave Symposium

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A large-signal model is presented for HBT's. The model accounts for self-heating effects and is based 0 1 1 the GummelPoon formulation. Full model compatibility with the com mercially available software pack age LIBRA is ensured. Thc, rnodrl incorporates tempera1 ure dependence for most of its parameters and has been employed for the analy~is of the DC and microwave power characteristics of AlC:a,Ss/GaAs HBT 's. Good a p e m e n t , between siniulated and directly measured TIC and microwave characteristic5

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Modeling of self-heating in GaAs/AlGaAs HBTs for accurate circuit and device analysis

Cited by 16 publications

References 4 publications

Physical heterojunction bipolar transistor model for microwave large signal simulation

Physical heterojunction bipolar transistor model for microwave large signal simulation

Current gain collapse in HBTs analysed by transient interferometric mapping method

A heterojunction bipolar transistor large-signal model for high power microwave applications

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