Transient self-heating effects in multifinger AlGaN/GaN HEMTs with metal airbridges

Kuzmı́k, J.; Bychikhin, S.; Lossy, R.; Wurfl, Hans-Joachim; Poisson, M.A.; Teyssier, Jean-Pierre; Gaquière, Christophe; Pogány, D.

doi:10.1016/j.sse.2007.04.001

Cited by 11 publications

(8 citation statements)

References 16 publications

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“…One classical method for extracting T C and R TH is by comparing temperature-dependent fastpulsed measurements with dc measurements; examples of application to AlGaN/GaN HEMTs can be found in [15]- [17].…”

mentioning

confidence: 99%

Temperature-Dependent Characterization of AlGaN/GaN HEMTs: Thermal and Source/Drain Resistances

Menozzi

Umana‐Membreno

Nener

et al. 2008

IEEE Trans. Device Mater. Relib.

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This paper shows the application of simple dc techniques to the temperature-dependent characterization of AlGaN/ GaN HEMTs in terms of the following: 1) thermal resistance and 2) ohmic series resistance (at low drain bias). Despite their simplicity, these measurement techniques are shown to give valuable information about the device behavior over a wide range of ambient/channel temperatures. The experimental results are validated by comparison with independent measurements and numerical simulations.Index Terms-Gallium compounds, microwave power transistors, MODFETs, power HEMTs, semiconductor-device measurements, semiconductor-device thermal factors, wide bandgap semiconductors, III nitrides, III-V semiconductors.

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confidence: 99%

Temperature-Dependent Characterization of AlGaN/GaN HEMTs: Thermal and Source/Drain Resistances

Menozzi

Umana‐Membreno

Nener

et al. 2008

IEEE Trans. Device Mater. Relib.

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“…3 at t ¼ 10 ms with marked areas S A and S B below the source and the drain contacts. After [22]. Fig.…”

Section: C) Investigation Of Tbr At Different Iii-nitride/substrate Imentioning

confidence: 99%

“…Calculated and experimental time evolution of the temperature increase in the channel of HEMT during the 10 V pulse. After [22]. 1 mW/mm 2 .…”

Section: C) Investigation Of Tbr At Different Iii-nitride/substrate Imentioning

confidence: 99%

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Self-heating phenomena in high-power III-N transistors and new thermal characterization methods developed within EU project TARGET

Kuzmı́k

Bychikhin

Pichonat

et al. 2009

Int. j. microw. wirel. technol.

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In the framework of the Top Amplifier Research Groups in a European Team (TARGET) project, we developed a new electrical method for the temperature measurement of HEMTs and performed several unique studies on the self-heating effects in AlGaN/GaN HEMTs. This method, in combination with transient interferometric mapping (TIM), provides a fundamental understanding of the heat propagation in a transient state of HEMTs. The AlGaN/GaN/Si HEMT thermal resistance was determined to be ~70 K/W after 400 ns from the start of a pulse, and the heating time constant was ~200 ns. Our experimental methods were further applied on multifinger high-power AlGaN/GaN/sapphire HEMTs. The TIM method indicates that the airbridge structure serves as a cooler, removing approximately 10% of the heat energy. In the next study we used TIM and the micro-Raman technique to quantify thermal boundary resistance (TBR) between different wafer materials and GaN epi-structure. We found TBR to be ~7 × 10⁻⁸ m²K/W for GaN/Si and ~1.2 × 10⁻⁷ m²K/W for GaN/SiC interfaces. The role of TBR at the GaN/sapphire interface was found to be less important

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“…A larger simulated phase shift compared to experiments can be explained by a heat transfer from the semiconductor to the top metal (i.e. the cooling effect, see [17,19]) which reduces the temperature in the GaAs substrate probed by TIM. From the known onset of the collapse effect at about 1ms, the simulation gives a temperature rise at the onset of about 300K.…”

Section: Introductionmentioning

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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Transient self-heating effects in multifinger AlGaN/GaN HEMTs with metal airbridges

Cited by 11 publications

References 16 publications

Temperature-Dependent Characterization of AlGaN/GaN HEMTs: Thermal and Source/Drain Resistances

Temperature-Dependent Characterization of AlGaN/GaN HEMTs: Thermal and Source/Drain Resistances

Self-heating phenomena in high-power III-N transistors and new thermal characterization methods developed within EU project TARGET

Current gain collapse in HBTs analysed by transient interferometric mapping method

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