Properties and ion implantation of Al<i>x</i>Ga1−<i>x</i>N epitaxial single crystal films prepared by low pressure metalorganic chemical vapor deposition

Khan, M. Asif; Skogman, R. A.; Schulze, R. G.; Gershenzon, M.

doi:10.1063/1.94363

Cited by 102 publications

(33 citation statements)

References 6 publications

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“…As the energy of the conduction band approaches that of the defect level, it becomes energetically less favorable for defects to be ionized and a "freeze out" of carriers originating from these defects is observed (Yoshida 1982, Khan 1983, Koide 1986, Zhang 1995. This is the same reduction in carrier concentration observed in GaN under large hydrostatic pressures (perlin 1995, Wetzel 1996).…”

Section: Al_gan Allovssupporting

confidence: 58%

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Donor spectroscopy at large hydrostatic pressures and transport studies in compound semiconductors

Hsu

1997

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Section: Al_gan Allovssupporting

confidence: 58%

“…Finally, in figures 2-8a through 2-8d, the calculated mobilities are plotted together with experimentally obtained data points (Yoshida 1982, Khan 1983, Koide 1986, Zhang 1995. In two out of the four sets of data (Yoshida 1982, Koide 1986), the mobility can be seen to remain roughly constant except for a slight drop near A1 alloying fractions of 0.2.…”

Section: )mentioning

confidence: 99%

Donor spectroscopy at large hydrostatic pressures and transport studies in compound semiconductors

Hsu

1997

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“…AI~.Gal_~N layers grown by MBE under high vacuum conditions are inferior to those grown by HVPE at atmospheric pressure (4) and metalorganic vapor-phase epitaxy (MOVPE) (7). This is probably due to the high equilibrium pressure of nitrogen over the alloy at typical growth temperatures resulting in high density of nitrogen vacancies, which may behave as electron donors.…”

mentioning

confidence: 83%

“…MOVPE has proven its suitability for the epitaxial growth of GaN of good quality (8), but very few works have been reported on this AlxGa~_~N alloy. Recently, Khan et al (7) reported:the electrical and optical properties of AI~Gal_xN singlecrystal layers over the whole range of the composition prepared by using the low pressure MOVPE. However, no investigations of the controllability of the composition and the composition dependence of lattice constant were reported.…”

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confidence: 99%

Epitaxial Growth and Properties of Al x Ga1 − x N by MOVPE

Koide

Itoh

Sawaki

et al. 1986

J. Electrochem. Soc.

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Epitaxial layers of AI~Ga~_.~N alloys are grown on sapphire (0001) and silicon (111) substrates by MOVPE in an ambient H2 gas at atmospheric pressure. By optimizing the reactor design and the growth conditions, parasitic reactions of metalorganic compounds with gaseous NH3 are remarkably reduced and the composition of AI~Ga~_~N layers can be controlled fairly well for the first time. The vapor-solid distribution coefficient for A1 is found to be approximately unity. At respective substrate temperatures of 1020~ for sapphire and 1050~ for silicon, single-crystal layers of AI~Ga~_~N with x up to 0.40 are obtained. The lattice constant is proportional to the molar fraction of A1N following Vegard's law. The electrical resistivity, carrier concentration, and Hall mobility of the layers are studied as a function of the composition.GaN and A1N have attracted much interest as the materials for optical devices in the short wavelength region, because they have direct energy bandgap of 3.4 (1) and 6.2 eV (2) at room temperature, respectively. For such device applications, single crystals with desired electrical properties are required. However, it has been fairly difficult to control their electrical Properties such as the type of conduction and the conductivity. As-grown GaN is usually an n-type material with relatively low resistivity, while A1N is always insulating. It is interesting to study, therefore, the growth of their alloy At~Ga~_xN single crystals and the properties of this alloy, because both GaN and AIN have a wurtzite structure. Although few reports of the growth of this alloy have appeared during the last several years, all of these reports have shown that the control of composition of the alloy is yet to be achieved for single crystals with good electrical properties.The growth of AI~GaI_~N layers by hydride vaporphase epitaxy (HVPE) was reported by Hagen et al. AI~.Gal_~N layers grown by MBE under high vacuum conditions are inferior to those grown by HVPE at atmospheric pressure (4) and metalorganic vapor-phase epitaxy (MOVPE) (7). This is probably due to the high equilibrium pressure of nitrogen over the alloy at typical growth temperatures resulting in high density of nitrogen vacancies, which may behave as electron donors. Furthermore, the lattice constant was not proportional to the molar fraction of A1N, suggesting the presence of some kinds of lattice defect. MOVPE has proven its suitability for the epitaxial growth of GaN of good quality (8), but very few works have been reported on this AlxGa~_~N alloy. Recently, Khan et al. (7) reported:the electrical and optical properties of AI~Gal_xN singlecrystal layers over the whole range of the composition prepared by using the low pressure MOVPE. However, no investigations of the controllability of the composition and the composition dependence of lattice constant were reported. In this paper, we report the epitaxial growth of AI~Gal_xN layers on sapphire and silicon substrates by MOVPE at atmospheric pressure and the achievement of good control o...

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“…Several theoretical calculations have been directed at the properties of the technologically important cation-substituted nitride alloys [29][30][31]. From 32-atom supercells in the wurtzite (zinc blende) structure, van Schilfgaarde calculated the bowing parameter in the cation-substituted nitrides [2] [30,31] and ~1 eV [32,33]. More dramatic changes in the energy bands are observed in the anion-substituted nitride alloys.…”

Section: Electronic Propertiesmentioning

confidence: 99%

Computational Materials Science, an Increasingly Reliable Engineering Tool: Anomalous Nitride Band Structures and Device Consequences

Sher

Schilfgaarde

Berding

et al. 1999

MRS Internet j. nitride semicond. res.

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Computational materials science has evolved in recent years into a reliable theory capable of predicting not only idealized materials and device performance properties, but also those that apply to practical engineering developments. The codes run on workstations and even now are fast enough to be useful design tools. A review will be presented of the current status of this rapidly advancing field. Examples of the accuracy of the codes are displayed by comparing the predicted atomic volumes, and cohesive and excess energies of several materials with experiment. As a further demonstration of the methods, the band structures of AlN, GaN, and InN in wurtzite and zinc blende structures will be presented. There are anomalies in the conduction and valence bands of these materials. Some consequences on light emitting and power devices made from these materials will be examined.

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Properties and ion implantation of AlxGa1−xN epitaxial single crystal films prepared by low pressure metalorganic chemical vapor deposition

Cited by 102 publications

References 6 publications

Donor spectroscopy at large hydrostatic pressures and transport studies in compound semiconductors

Donor spectroscopy at large hydrostatic pressures and transport studies in compound semiconductors

Epitaxial Growth and Properties of Al x Ga1 − x N by MOVPE

Computational Materials Science, an Increasingly Reliable Engineering Tool: Anomalous Nitride Band Structures and Device Consequences

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