Doping Effects of Group-III and -V Element on a-Si Prepared by High Pressure rf Sputtering

AbstractGroup III-nitride compound semiconductors (e.g. AlN-GaN-InN) have generated considerable interest for use in advanced optoelectronic device structures. The fabrication of multi-tandem solar cells, high-speed optoelectronics and solid state lasers operating at higher energy wavelengths will be made possible using (Ga1-y-xAlyInx)N heterostructures due to their robustness against radiation and the wide spectral application range. To date, the growth of indium rich (In1-xGax)N films and heterostructures remains a challenge, primarily due to the large thermal decomposition pressures in indium rich group III-nitride alloys at the optimum growth temperatures. In order to control the partial pressures during the growth process of InN and related alloys, a unique high-pressure chemical vapor deposition (HPCVD) system with integrated real-time optical monitoring capabilities has been developed. We report initial results on InN layers grown at temperatures as high as ∼850°C with reactor pressures around 15 bar. Such process conditions are a major step towards the fabrication of indium rich group III-nitride heterostructures that are embedded in wide band gap group III-nitrides. Real-time optical characterization techniques are applied in order to study the gas phase kinetics and surface chemistry processes during the growth process.For an ammonia to TMI precursor flow ratio below 500, multiple phases with sharp XRD features are observed. Structural analysis perform by Raman scattering techniques indicates that the E2 high mode improves as NH3:TMI ratio is decreased to below 500. Optical characterization of these InN layers indicates that the absorption edge shifts from down from 1.85 eV to 0.7 eV. This shift seems to be caused by a series of localized absorption centers that appear as the indium to nitrogen stoichiometry varies. This contribution will correlate the process parameters to results obtained by XRD, Raman spectroscopy and optical spectroscopy, in order to assess the InN film properties.

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Band Structure, Metallization and Superconducting Transition Of Group III-V Semiconductors AlP And AlAs Under High Pressure

Chemical and Materials Engineering ◽

10.13189/cme.2013.010405 ◽

2013 ◽

Vol 1 (4) ◽

pp. 132-140

Author(s):

V. Benaline Sheeba ◽

C. Nirmala Louis

Keyword(s):

High Pressure ◽

Band Structure ◽

Superconducting Transition ◽

Group Iii V Semiconductors ◽

Group Iii

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Properties of InN layers grown by High Pressure CVD

MRS Proceedings ◽

10.1557/proc-0955-i08-04 ◽

2006 ◽

Vol 955 ◽

Author(s):

Mustafa Alevli ◽

Goksel Durkaya ◽

Ronny Kirste ◽

Aruna Weesekara ◽

Unil Perera ◽

...

Keyword(s):

High Pressure ◽

High Speed ◽

Growth Parameters ◽

Free Carrier ◽

Dielectric Constants ◽

High Quality ◽

Group Iii ◽

High Efficient ◽

Nitride Alloys ◽

Group Iii Nitride

ABSTRACTIndium nitride (InN) and indium-rich group III-nitride alloys are promising materials for advanced optoelectronic device applications. Indium-rich alloys, e.g. (Ga1-y-xAlyInx)N will enable the fabrication of high-efficient light emitting diodes tunable in the whole visible spectral region, as well as advanced high speed optoelectronics for optical communication operating. The present limitation in this area is the growth of high quality InN and indium-rich group III-nitride alloys as documented in many controversial reports on the true physical properties of InN. The difficulties arise from the low dissociation temperature of InN that requires an extraordinarily high nitrogen overpressure to stabilize the material up to optimum growth temperatures. We developed a novel “high-pressure chemical vapor deposition” (HPCVD) system, capable to control and analyze the vast different partial pressures of the constituents. Our results show that the chosen HPCVD pathway leads to high-quality single crystalline InN, demonstrating that HPCVD is a viable tool for the growth of indium rich group III nitride alloys. The structural analysis of InN deposited on GaN-sapphire substrate by XRD show single phase InN(0002) peaks with full width half maximum (FWHM) around 400 arcsec. Infrared reflectance spectroscopy is used to analyze the plasmon frequencies, high frequency dielectric constants, the free carrier concentrations and carrier mobilities in these layers. For nominal undoped InN layers, free carrier concentrations in the mid 1019 cm−3 and mobilities around 600 cm−2-V-1-s-1 are observed. Further improvements are expected as the growth parameters are optimized. The explored growth parameters are close to of those employed for GaN growth conditions, which is a major step towards the fabrication of indium rich (Ga1−y−xAlyInx)N alloys and heterostructures.

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