Thermal stabilization of power HBTs using n-AlxGa1−xAs emitter ballast resistors with high thermal coefficient of resistance

Twynam, J.K.; Yagura, M.; Kishimoto, Katsuhiro; Kinosada, T.; Sato, H.

doi:10.1016/0038-1101(95)00050-4

Cited by 14 publications

(2 citation statements)

References 6 publications

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“…The used GaAs n ‡ emitter layer has a value of around 10 ¡3 K ¡1 , which may be improved to 8 £ 10 ¡3 K ¡1 if the Al 0:3 Ga 0:7 As emitter layer only in the structure could be used (Twynam et al 1995) .…”

Section: Discussionmentioning

confidence: 99%

A study of L-band GaAlAs/GaAs HBTs for high-voltage RF-power

Johansson¹,

Söderström²,

Eastman³

et al. 2000

International Journal of Electronics

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The feasibility of GaAlAs/GaAs heterojunction bipolar transistors as power output transistors for 24± 28 V cellular base station applications was studied. A 1 W, 25 V test vehicle was fabricated, with predictable and uniform electrical parameters. Maximum output power was 1.02 W with 9.1 dB gain at 2 GHz and 18 V supply voltage. Characterization at more than 22 V destroyed all devices, even if emitter ballasting resistors were used for thermal balance. Analysis indicated that the failures were caused by too wide emitters in combination with the high supply voltage, causing current crowding and large temperature spikes. Small (< 2-3 mm) horizontal emitter dimensions are required even with low base sheet resistivity, otherwise leading to destructive temperature non-uniformities, unless special arrangements to drastically reduce the thermal resistance can be applied.

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Section: Discussionmentioning

confidence: 99%

A study of L-band GaAlAs/GaAs HBTs for high-voltage RF-power

Johansson¹,

Söderström²,

Eastman³

et al. 2000

International Journal of Electronics

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“…A thick, highly doped base layer is used to give low TED resistance (base transit time is relatively unimportant in this device). The AlGaAs ballast layer has a 35% Al mole fraction and high doping density to give good current uniformity within the emitter finger without current saturation [6].…”

mentioning

confidence: 99%

Demonstration of a 77-GHz heterojunction bipolar transferred electron device

Twynam

Yagura

Takahashi

et al. 2000

IEEE Electron Device Lett.

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We demonstrate for the first time a heterojunction bipolar transferred electron device (HBTED), a device with a bipolar transistor-like structure in which Gunn oscillations occur. The use of a graded doping profile in the collector region is, we believe, a key factor in the device design. AlGaAs/GaAs HBTED's fabricated on semi-insulating GaAs substrates exhibit free-running oscillations at a frequency of around 77 GHz. The third (emitter) terminal enables this device to be injection-locked and to function as a self-oscillating mixer.

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