Metal contacts to n-type GaN

Schmitz, A. C.; Ping, A. T.; Khan, M. Asif; Chen, Q.; Yang, Jin Min; Adesida, I.

doi:10.1007/s11664-998-0396-5

Cited by 177 publications

(111 citation statements)

References 19 publications

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“…A number of metals have been investigated for AlGaN/GaN and InAlN/GaN HEMT structures, such as Ni, platinum (Pt), molybdenum (Mo), Cu, and iridium (Ir) [28]- [31] with Ni being the most commonly used contact metal. Usually, Au is used as a conductive overlay.…”

Section: Schottky Contactsmentioning

confidence: 99%

Testing the Temperature Limits of GaN-Based HEMT Devices

Maier

Alomari

Grandjean

et al. 2010

IEEE Trans. Device Mater. Relib.

127

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Section: Schottky Contactsmentioning

confidence: 99%

Testing the Temperature Limits of GaN-Based HEMT Devices

Maier

Alomari

Grandjean

et al. 2010

IEEE Trans. Device Mater. Relib.

127

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“…Precise and reliable control of the depletion layer width by the Schottky contact without leakage currents is extremely important in these devices. However, GaN-based Schottky interfaces are known to suffer from unusually large leakage currents under reverse bias [1][2][3]. Excess leakage currents through a Schottky gate strongly affects, not only gate-control and power consumption, but also the noise performance in GaN-based FET devices as recently pointed out [4].…”

Section: Introductionmentioning

confidence: 99%

Mechanism of current leakage through metal/n-GaN interfaces

Oyama

Hashizume

Hasegawa

2002

Applied Surface Science

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Detailed current-voltage-temperature (I-V-T) measurements were performed on the Schottky diodes fabricated on MOVPE-grown n-GaN layers. A large deviation from the thermionic emission (TE) transport was observed in the reverse I-V curves with a large excess leakage. From the calculation based on the thermionic-field emission (TFE) model, it was found that the tunneling plays an important role in the carrier transport across the GaN Schottky barrier even for doping densities as low as 1 x 10 17 cm -3 . A novel barrier-modified TFE model based on presence of near-surface fixed charges or surface states is proposed to explain the observed large reverse leakage currents.

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“…In particular, leakage currents through Schottky contacts not only impede device reliability but also degrade power efficiency and noise performance in such devices. In spite of the fact that Schottky diodes formed on GaN and AlGaN are suffering from excess reverse leakage currents that are many orders of magnitude larger than the prediction of the thermionic emission ͑TE͒ model, [1][2][3][4][5][6] only a few studies have focused on the reverse-current characteristics quantitatively.…”

mentioning

confidence: 99%

Leakage mechanism in GaN and AlGaN Schottky interfaces

Hashizume¹,

Kotani²,

Hasegawa³

2004

Applied Physics Letters

182

112

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Based on detailed temperature-dependent current-voltage (I -V -T) measurements the mechanism of leakage currents through GaN and AlGaN Schottky interfaces is discussed. The experiments were compared to calculations based on thin surface barrier model in which the effects of surface defects were taken into account. Our simulation method reproduced the experimental I -V -T characteristics of the GaN and AlGaN Schottky diodes, and gave excellent fitting results to the reported Schottky I -V curves in GaN for both forward and reverse biases at different temperatures. The present results indicate that the barrier thinning caused by unintentional surface-defect donors enhances the tunneling transport processes, leading to large leakage currents through GaN and AlGaN Schottky interfaces. © 2004 American Institute of Physics. ͓DOI: 10.1063/1.1762980͔ Although significant progress has been achieved in GaNbased high-power/high-frequency electronic devices and ultraviolet photodetectors, surface-related problems still need an immediate solution. In particular, leakage currents through Schottky contacts not only impede device reliability but also degrade power efficiency and noise performance in such devices. In spite of the fact that Schottky diodes formed on GaN and AlGaN are suffering from excess reverse leakage currents that are many orders of magnitude larger than the prediction of the thermionic emission ͑TE͒ model, 1-6 only a few studies have focused on the reverse-current characteristics quantitatively.Yu et al. 7 and Miller et al. 8 discussed the leakage mechanism in GaN and AlGaN Schottky interfaces on the basis of the field-emission ͑FE͒ tunneling transport assuming a triangular Schottky potential. However, unreasonably higher donor densities than the actual doping concentration were required in their calculation for reproduction of the experimental data. Thus, they expected some other processes such as defect-assisted tunneling to enhance leakage currents. Other groups also suggested the trap-assisted tunneling model to explain the leakage mechanism in the reverse bias region. 2,9 However, such model requires an unlikely multistep tunneling process or defect continuum with a wide energy band throughout a depletion region in semiconductor. Sawada et al. 10 proposed a surface patch model to explain forward current characteristics. Miller et al. 11 have recently suggested a leakage mechanism associated with a variablerange-hopping conduction through threading dislocations. However, little is known for the physical mechanism of excess leakage currents in GaN and AlGaN Schottky diodes.This letter discusses the mechanism of leakage currents through GaN Schottky interfaces, investigating transport properties of Schottky diodes using temperature-dependent current-voltage (I -V -T) measurements for both forward and reverse biases. A simulation method for the calculation of currents based on the thin surface barrier ͑TSB͒ model 5 is discussed. The measured currents were compared to the calculated ones for different tempe...

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Metal contacts to n-type GaN

Cited by 177 publications

References 19 publications

Testing the Temperature Limits of GaN-Based HEMT Devices

Testing the Temperature Limits of GaN-Based HEMT Devices

Mechanism of current leakage through metal/n-GaN interfaces

Leakage mechanism in GaN and AlGaN Schottky interfaces

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