Current-voltage characteristics and interface state density of GaAs Schottky barrier

Maeda, Keiji; Ikoma, Hideaki; Satô, Kenji; Ishida, Toshiki

doi:10.1063/1.109296

Cited by 45 publications

(21 citation statements)

References 5 publications

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“…In Fig. 3(b), note that the n value has a bell-shaped behavior with its maximum at around 0.08 V, which is indicative of the presence of surface states, as reported for GaAs [52], InP [53], and GaN [54]. Assuming that these surface states are in equilibrium with the GaN, the density of surface states (D s ) can be estimated according to Nano Res.…”

Section: Resultsmentioning

confidence: 94%

Graphene-GaN Schottky diodes

et al. 2014

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The electrical characteristics of graphene Schottky contacts formed on undoped GaN semiconductors were investigated. Excellent rectifying behavior with a rectification ratio of ~10 7 at ±2 V and a low reverse leakage current of 1.0 × 10 -8 A/cm 2 at -5 V were observed. The Schottky barrier heights, as determined by the thermionic emission model, Richardson plots, and barrier inhomogeneity model, were 0.90, 0.72, and 1.24 ± 0.13 eV, respectively. Despite the predicted low barrier height of ~0.4 eV at the graphene-GaN interface, the formation of excellent rectifying characteristics with much larger barrier heights is attributed to the presence of a large number of surface states (1.2 × 10 13 states/cm 2 /eV) and the internal spontaneous polarization field of GaN, resulted in a significant upward surface band bending or a bare surface barrier height as high as of 2.9 eV. Using the S parameter of 0.48 (measured from the work function dependence of Schottky barrier height) and the mean barrier height of 1.24 eV, the work function of graphene in the Au/graphene/GaN stack could be approximately estimated to be as low as 3.5 eV. The obtained results indicate that graphene is a promising candidate for use as a Schottky rectifier in GaN semiconductors with n-type conductivity.

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Section: Resultsmentioning

confidence: 94%

Graphene-GaN Schottky diodes

et al. 2014

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“…The deviation of a real Schottky interface from the ideal ͑n =1͒ can be attributed to many effects, such as electron trapping and recombination, 21 barrier inhomogeneities, 22 an interfacial oxide layer, 23 image force lowering, 24 shunt resistance, 25 and series resistance. 26 In the two-terminal Schottky I-V measurement, comparing to an ideal Schottky diode, the EEC device has a built-in series resistance.…”

Section: A Schottky I-vmentioning

confidence: 99%

Transport measurements and analytical modeling of extraordinary electrical conductance in Ti-GaAs metal-semiconductor hybrid structures

Newaz

Wang

et al. 2009

Phys. Rev. B

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We present a comprehensive study of a phenomenon, extraordinary electroconductance ͑EEC͒, in microscopic metal-semiconductor hybrid ͑MSH͒ structures at room temperature. Our artificially designed MSH structure shows highly efficient external electric field sensing properties not exhibited by bare semiconductor structures. The microscopic device is fabricated from a GaAs epitaxial layer with a Ti/Au shunt subject to an external electric field and gives a maximum 5.2% EEC effect corresponding to an external electric field resolution of 3.05 V/cm at a bias field of 2.5 kV/cm. Moreover, the study reveals a strong dependence of the transport properties on the geometry of the MSH. An analytical two-layer model is developed which provides good agreement with the experimentally observed data. We propose that scaled down nanoscopic EEC sensor arrays can be used as an imaging technique for the charge distribution on a single cell surface in real time.

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“…The ideality factor of a Schottky diode depends in part on the concentration of defect states near the interface with the metal [4]. We find that KOH etching of GaN before evaporation of metals decreases the ideality factor.…”

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confidence: 93%

“…The formation of the deep traps is a factor decreasing the concentration of p-type carriers. The results of the calculations are compared with the experimental evidence of stacking faults in GaN obtained from high resolution transmission electron microscopy (TEM).The ideality factor of a Schottky diode depends in part on the concentration of defect states near the interface with the metal [4]. We find that KOH etching of GaN before evaporation of metals decreases the ideality factor.…”

mentioning

confidence: 93%

Point and extended defects in the bulk and at the interface of GaN with metals

Batyrev

Jones

Shah

et al. 2009

2009 International Semiconductor Device Research Symposium

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GaN devices promise advantages over other compound semiconductors that include higher power amplification, increased linearity, and less temperature dependent degradation. The enhanced concentration of defects in MOCVD (Metal Organic Vapor Deposition) grown GaN is a bottleneck for achieving these superior properties. We present results of calculations of typical point and extended defects in GaN and possible defects at the contacts of GaN with metals. Point defects are separated into intentional Si, Mg, Fe and unintentional O, V N , V Ga impurities. Extended defects are partial dislocations and stacking faults formed during island growth regime (typical for MOCVD) in concentrations of ~ 2-4 orders of magnitude higher than that for MBE (Molecular Beam Epitaxy) or HVPE (Hydride Vapor Phase Epitaxy) for the same thickness.For modeling we used the density functional method with projector augmented waves and neutral defects were introduced into a 72 atom unit cell of GaN. Si and O we found to be shallow donors and Mg a shallow acceptor, Fe dopants and Ga vacancies are acceptors, N vacancies show donor behavior (Fig.1). The results on Si, Mg impurities and Ga, Ni -vacancies are in general agreement with [1-2]. One can imagine complexes V N -Mg or V Ga -O compensating each other, but the probability of the realization of these complexes is much lower than that of individual defectsThe density functional theory and supercell-cluster hybrid approach [3] were used to model the dislocations' core structure and intrinsic stacking faults. We considered dissociation of a 60 ºdislocation in wurtzite into a pair of Shockley partials (SP): 30 º glide and 90 º single and double period glide with both Ga and N cores. Formation of the partials results in a variety of defect levels in the band gap of GaN. The deepest defect levels (1.1 eV from CBM) are related to dangling bonds in the dislocation core. We also calculated the segregation of the n-dopant, Si or O, and the p-dopant, Mg, to the dislocation core. All of the dopants have an energy gain (0.2-0.4 eV) after segregation to the dislocation core of a SP 30 º glide. The intrinsic stacking fault (…AaBbCcAaCc…) with two violations of the wurtzite stacking sequence (…AaBbAaBb…) was considered between the Shockley partial (SP) dislocations in the system of SP 30º single period glide -intrinsic stacking fault -SP 90º single period glide (Fig.2). For this system we found a slight narrowing of the band gap in addition to the formation of deep occupied defect levels ~ 0.7-0.8 eV from the VBM. The formation of the deep traps is a factor decreasing the concentration of p-type carriers. The results of the calculations are compared with the experimental evidence of stacking faults in GaN obtained from high resolution transmission electron microscopy (TEM).The ideality factor of a Schottky diode depends in part on the concentration of defect states near the interface with the metal [4]. We find that KOH etching of GaN before evaporation of metals decreases the ideality factor. Our first-princ...

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Current-voltage characteristics and interface state density of GaAs Schottky barrier

Cited by 45 publications

References 5 publications

Graphene-GaN Schottky diodes

Graphene-GaN Schottky diodes

Transport measurements and analytical modeling of extraordinary electrical conductance in Ti-GaAs metal-semiconductor hybrid structures

Point and extended defects in the bulk and at the interface of GaN with metals

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