Effects of interfacial oxides on Schottky barrier contacts to <i>n</i>- and <i>p</i>-type GaN

Cao, X. A.; Pearton, S. J.; Dang, G.; Zhang, A. P.; Ren, F.; Hove, J. M. Van

doi:10.1063/1.125559

Cited by 87 publications

(50 citation statements)

References 14 publications

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“…In addition, the work done by Liu et al has shown that the Ga peak becomes larger when samples are cleaned in (NH 4 ) 2 S than in HF/HCl [15]. Furthermore, (NH 4 ) 2 S has been found to reduce the barrier height on GaN, and preventing re-oxidation of the surface [16]. We suggest that there exist Ga-Cl and Ga-S on sample 1 and sample 2, respectively.…”

Section: Diale Fd Auret / Physica B ] (]]]]) ]]]-]]]mentioning

confidence: 54%

Effects of chemical treatment on barrier height and ideality factors of Au/GaN Schottky diodes

Diale

Auret

2009

Physica B: Condensed Matter

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a b s t r a c tWe have studied Au/n-GaN Schottky barrier diodes. GaN surfaces have been prepared by cleaning in HCl and (NH 4 ) 2 S prior to metal deposition. The zero-biased barrier heights and ideality factors obtained from the current-voltage characteristics differ from diode to diode, although all the samples were prepared identically. The statistical analysis for the reverse bias C-V data yielded mean value of (1.357 0.04) eV for Schottky barrier height of HCl treated sample and (1.20 7 0.03) eV for (NH 4 ) 2 S sample, where 9 dots were considered from each cleaning method. It was found that the barrier height values obtained from the C À 2 -V (1.43 eV) and I-V characteristics (0.89 eV) are different from each other by 0.54 eV. The inhomogeneous barrier heights were found to be related to the effect of the high series resistance on diode parameters [1].

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Section: Diale Fd Auret / Physica B ] (]]]]) ]]]-]]]mentioning

confidence: 54%

Effects of chemical treatment on barrier height and ideality factors of Au/GaN Schottky diodes

Diale

Auret

2009

Physica B: Condensed Matter

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“…[7][8][9][21][22][23][24] The activation energy of the Mg acceptor level is taken at ͑ E t -E v )ϭ0.16 eV. The Schottky barrier height q b is taken 0.70 eV.…”

Section: A Schottky Gan:mg Junction Under Room Temperature Zero-biamentioning

confidence: 99%

“…The Schottky barrier height q b is taken 0.70 eV. [21][22][23] The hole surface recombination velocity is taken 10 9 cm/s. Fig.…”

Section: A Schottky Gan:mg Junction Under Room Temperature Zero-biamentioning

confidence: 99%

Competition between deep impurity and dopant behavior of Mg in GaN Schottky diodes

Schmeits

Nguyen

Germain

2001

Journal of Applied Physics

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The effect of the deep acceptor Mg on the electrical characteristics of p-doped GaN Schottky diodes is analyzed. The theoretical study is based on the numerical resolution of the basic semiconductor equations, including the continuity equation for the Mg-related acceptor level. It gives the steady-state and small-signal analysis of p-doped GaN:Mg Schottky diodes, yielding as final result the frequency dependent capacitance and conductance of the structure. It is shown that the low-frequency characteristics are determined by the carrier exchange between the Mg related impurity level and the valence band, whereas above the impurity transition frequency, the hole modulation of the depletion layer edge governs the electrical response. Detailed results are shown on the effect of temperature, applied steady-state voltage and series resistance. The study of two back-to-back connected GaN Schottky diodes reveals the appearance of typical features in the electrical characteristics, depending on the respective Schottky barrier height of the two junctions.

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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.…”

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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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Effects of interfacial oxides on Schottky barrier contacts to n- and p-type GaN

Cited by 87 publications

References 14 publications

Effects of chemical treatment on barrier height and ideality factors of Au/GaN Schottky diodes

Effects of chemical treatment on barrier height and ideality factors of Au/GaN Schottky diodes

Competition between deep impurity and dopant behavior of Mg in GaN Schottky diodes

Leakage mechanism in GaN and AlGaN Schottky interfaces

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