Drain current compression in GaN MODFETs under large-signal modulation at microwave frequencies

Nguyen, C.; Nguyen, Nam X.; Grider, David

doi:10.1049/el:19990957

Cited by 131 publications

(51 citation statements)

References 6 publications

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“…Significant advances have been made in the fabrication of these devices: Nitride-based field-effect transistors ͑FETs͒ have been reported to exhibit continuous wave outputs up to 6.9 W/mm 1 and high frequency operation 2 at f T ϭ67 GHz and f max ϭ140 GHz. While attainable device characteristics continue to improve, the reproducibility of these characteristics has become problematic, 3 due to device limitations resulting from trapping effects. 3,4 In addition to compensating intentionally doped material, such traps can produce persistent photoconductivity ͑PPC͒ effects and current collapse.…”

Section: Introductionmentioning

confidence: 99%

“…While attainable device characteristics continue to improve, the reproducibility of these characteristics has become problematic, 3 due to device limitations resulting from trapping effects. 3,4 In addition to compensating intentionally doped material, such traps can produce persistent photoconductivity ͑PPC͒ effects and current collapse. Current collapse refers to the trapping of charge at defects, after the application of a high drain-source voltage, which results in a significant reduction in the drain current.…”

Section: Introductionmentioning

confidence: 99%

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Photoionization spectroscopy of traps in GaN metal-semiconductor field-effect transistors

Klein¹,

Binari²,

Freitas³

et al. 2000

Journal of Applied Physics

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Measurements of the spectral and intensity dependences of the optically-induced reversal of current collapse in a GaN metal-semiconductor field-effect transistor ͑MESFET͒ have been compared to calculated results. The model assumes a net transfer of charge from the conducting channel to trapping states in the high-resistivity region of the device. The reversal, a light-induced increase in the trap-limited drain current, results from the photoionization of trapped carriers and their return to the channel under the influence of the built-in electric field associated with the trapped charge distribution. For a MESFET in which two distinct trapping centers have been spectrally resolved, the experimentally measured dependence upon light intensity was fitted using this model. The two traps were found to have very different photoionization cross-sections but comparable concentrations (4ϫ10 11 cm Ϫ2 and 6ϫ10 11 cm Ϫ2 ͒, suggesting that both traps contribute comparably to the observed current collapse. ͓S0021-8979͑00͒00417-5͔

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photoionization spectroscopy of traps in GaN metal-semiconductor field-effect transistors

Klein¹,

Binari²,

Freitas³

et al. 2000

Journal of Applied Physics

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“…The so-called current collapse [1][2][3][4] and long-term stability are the most important problems preventing large-scale practical usage of nitride-based heterostructure field-effect transistors ͑HFETs͒ and metal-oxide-semiconductor HFETs ͑MOSHFETs͒ in ultra-high-power microwave systems. The current collapse manifests itself as a reduction of the device current when a large alternating signal is applied to the gate.…”

mentioning

confidence: 99%

Induced strain mechanism of current collapse in AlGaN/GaN heterostructure field-effect transistors

Simin

Koudymov

Tarakji

et al. 2001

Applied Physics Letters

112

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Gated transmission line model pattern measurements of the transient current–voltage characteristics of AlGaN/GaN heterostructure field-effect transistors (HFETs) and metal–oxide–semiconductor HFETs were made to develop a phenomenological model for current collapse. Our measurements show that, under pulsed gate bias, the current collapse results from increased source–gate and gate–drain resistances but not from the channel resistance under the gate. We propose a model linking this increase in series resistances (and, therefore, the current collapse) to a decrease in piezoelectric charge resulting from the gate bias-induced nonuniform strain in the AlGaN barrier layer.

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“…The phenomenon responsible for this degradation is generally referred as ''rf-current collapse'' or ''current slump,'' which recently has been a subject of several studies. [4][5][6][7][8][9] Drain currents under large input drives were measured showing significant current compression compared to the dc values. 4,5,8 Activation energies of deep traps responsible for the current collapse were studied by optical and thermoexcitation methods.…”

Section: Mechanism Of Radio-frequency Current Collapse In Gan-algan Fmentioning

confidence: 99%

“…[4][5][6][7][8][9] Drain currents under large input drives were measured showing significant current compression compared to the dc values. 4,5,8 Activation energies of deep traps responsible for the current collapse were studied by optical and thermoexcitation methods. 6,7 The surface passivation approach was suggested to increase the microwave output power.…”

Section: Mechanism Of Radio-frequency Current Collapse In Gan-algan Fmentioning

confidence: 99%

Mechanism of radio-frequency current collapse in GaN–AlGaN field-effect transistors

Tarakji

Simin

Il’inskaya

et al. 2001

Applied Physics Letters

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The mechanism of radio-frequency current collapse in GaN–AlGaN heterojunction field-effect transistors (HFETs) was investigated using a comparative study of HFET and metal–oxide–semiconductor HFET current–voltage (I–V) and transfer characteristics under dc and short-pulsed voltage biasing. Significant current collapse occurs when the gate voltage is pulsed, whereas under drain pulsing the I–V curves are close to those in steady-state conditions. Contrary to previous reports, we conclude that the transverse electric field across the wide-band-gap barrier layer separating the gate and the channel rather than the gate or surface leakage currents or high-field effects in the gate–drain spacing is responsible for the current collapse. We find that the microwave power degradation in GaN–AlGaN HFETs can be explained by the difference between dc and pulsed I–V characteristics.

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Drain current compression in GaN MODFETs under large-signal modulation at microwave frequencies

Cited by 131 publications

References 6 publications

Photoionization spectroscopy of traps in GaN metal-semiconductor field-effect transistors

Photoionization spectroscopy of traps in GaN metal-semiconductor field-effect transistors

Induced strain mechanism of current collapse in AlGaN/GaN heterostructure field-effect transistors

Mechanism of radio-frequency current collapse in GaN–AlGaN field-effect transistors

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