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Title: Growth and properties of GaN and AlN layers on silver substrates

Abstract

We report on the preparation and properties of GaN and AlN layers grown by molecular-beam epitaxy on silver metal substrates. X-ray diffraction rocking curves show polycrystalline character of GaN with high preferential GaN(11-22) orientation. An intermetallic phase of Ga{sub 3}Ag is found at the GaN/Ag interface. On the other hand, AlN layers exhibit a monocrystalline structure with a growth direction of (0002). Schottky diodes prepared on GaN layers show good rectifying behavior and relatively low leakage current ({approx}10{sup -3} A/cm{sup 2}). These results indicate that the III-nitride growth on metallic substrates might be used for low-cost and large-area electronic and photonic devices.

Authors:
; ; ; ; ; ; ; ;  [1];  [2];  [3];  [3];  [4];  [3]
  1. Max-Planck-Institute for Radioastronomy, Bonn, D-53121 Bonn (Germany)
  2. (Germany) and Institut fuer Hochfrequenztechnik, Technische Universitaet Braunschweig, Schleinitzstrasse 22, D-38106 Braunschweig (Germany)
  3. (Germany)
  4. (Czech Republic)
Publication Date:
OSTI Identifier:
20706433
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 87; Journal Issue: 21; Other Information: DOI: 10.1063/1.2135879; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM NITRIDES; CRYSTAL GROWTH; GALLIUM NITRIDES; INTERFACES; LAYERS; LEAKAGE CURRENT; MOLECULAR BEAM EPITAXY; NEUTRON DIFFRACTION; POLYCRYSTALS; SCHOTTKY BARRIER DIODES; SEMICONDUCTOR MATERIALS; SILVER; SUBSTRATES; X-RAY DIFFRACTION

Citation Formats

Mikulics, Martin, Kocan, Martin, Rizzi, Angela, Javorka, Peter, Sofer, Zdenek, Stejskal, Josef, Marso, Michel, Kordos, Peter, Lueth, Hans, Institute of Thin Films and Interfaces, Research Center Juelich, D-52425 Juelich, IV. Physikalisches Institut, Georg-August Universitaet Goettingen, D-37077 Goettingen, AMD, Wilschdorfer Landstrasse 101, 01109 Dresden, Department of Inorganic Chemistry, Institute of Chemical Technology, Technicka 5, Prague 6, and Institute of Thin Films and Interfaces and CNI-Center of Nanoelectronic Systems for Information Technology, Research Centre Juelich, D-52425 Juelich. Growth and properties of GaN and AlN layers on silver substrates. United States: N. p., 2005. Web. doi:10.1063/1.2135879.
Mikulics, Martin, Kocan, Martin, Rizzi, Angela, Javorka, Peter, Sofer, Zdenek, Stejskal, Josef, Marso, Michel, Kordos, Peter, Lueth, Hans, Institute of Thin Films and Interfaces, Research Center Juelich, D-52425 Juelich, IV. Physikalisches Institut, Georg-August Universitaet Goettingen, D-37077 Goettingen, AMD, Wilschdorfer Landstrasse 101, 01109 Dresden, Department of Inorganic Chemistry, Institute of Chemical Technology, Technicka 5, Prague 6, & Institute of Thin Films and Interfaces and CNI-Center of Nanoelectronic Systems for Information Technology, Research Centre Juelich, D-52425 Juelich. Growth and properties of GaN and AlN layers on silver substrates. United States. doi:10.1063/1.2135879.
Mikulics, Martin, Kocan, Martin, Rizzi, Angela, Javorka, Peter, Sofer, Zdenek, Stejskal, Josef, Marso, Michel, Kordos, Peter, Lueth, Hans, Institute of Thin Films and Interfaces, Research Center Juelich, D-52425 Juelich, IV. Physikalisches Institut, Georg-August Universitaet Goettingen, D-37077 Goettingen, AMD, Wilschdorfer Landstrasse 101, 01109 Dresden, Department of Inorganic Chemistry, Institute of Chemical Technology, Technicka 5, Prague 6, and Institute of Thin Films and Interfaces and CNI-Center of Nanoelectronic Systems for Information Technology, Research Centre Juelich, D-52425 Juelich. Mon . "Growth and properties of GaN and AlN layers on silver substrates". United States. doi:10.1063/1.2135879.
@article{osti_20706433,
title = {Growth and properties of GaN and AlN layers on silver substrates},
author = {Mikulics, Martin and Kocan, Martin and Rizzi, Angela and Javorka, Peter and Sofer, Zdenek and Stejskal, Josef and Marso, Michel and Kordos, Peter and Lueth, Hans and Institute of Thin Films and Interfaces, Research Center Juelich, D-52425 Juelich and IV. Physikalisches Institut, Georg-August Universitaet Goettingen, D-37077 Goettingen and AMD, Wilschdorfer Landstrasse 101, 01109 Dresden and Department of Inorganic Chemistry, Institute of Chemical Technology, Technicka 5, Prague 6 and Institute of Thin Films and Interfaces and CNI-Center of Nanoelectronic Systems for Information Technology, Research Centre Juelich, D-52425 Juelich},
abstractNote = {We report on the preparation and properties of GaN and AlN layers grown by molecular-beam epitaxy on silver metal substrates. X-ray diffraction rocking curves show polycrystalline character of GaN with high preferential GaN(11-22) orientation. An intermetallic phase of Ga{sub 3}Ag is found at the GaN/Ag interface. On the other hand, AlN layers exhibit a monocrystalline structure with a growth direction of (0002). Schottky diodes prepared on GaN layers show good rectifying behavior and relatively low leakage current ({approx}10{sup -3} A/cm{sup 2}). These results indicate that the III-nitride growth on metallic substrates might be used for low-cost and large-area electronic and photonic devices.},
doi = {10.1063/1.2135879},
journal = {Applied Physics Letters},
number = 21,
volume = 87,
place = {United States},
year = {Mon Nov 21 00:00:00 EST 2005},
month = {Mon Nov 21 00:00:00 EST 2005}
}
  • Severe surface decomposition of semi-insulating (SI) GaN templates occurred in high-temperature H{sub 2} atmosphere prior to epitaxial growth in a metalorganic chemical vapor deposition system. A two-step heating process with a surface stabilization technique was developed to preserve the GaN template surface. Utilizing the optimized heating process, a high two-dimensional electron gas mobility ∼2000 cm{sup 2}/V·s was obtained in a thin AlGaN/AlN/GaN heterostructure with an only 100-nm-thick GaN spacer layer homoepitaxially grown on the GaN template. This technique was also demonstrated viable for native GaN substrates to stabilize the surface facilitating two-dimensional growth of GaN layers. Very high residual silicon andmore » oxygen concentrations were found up to ∼1 × 10{sup 20 }cm{sup −3} at the interface between the GaN epilayer and the native GaN substrate. Capacitance-voltage measurements confirmed that the residual carbon doping controlled by growth conditions of the GaN epilayer can be used to successfully compensate the donor-like impurities. State-of-the-art structural properties of a high-mobility AlGaN/AlN/GaN heterostructure was then realized on a 1 × 1 cm{sup 2} SI native GaN substrate; the full width at half maximum of the X-ray rocking curves of the GaN (002) and (102) peaks are only 21 and 14 arc sec, respectively. The surface morphology of the heterostructure shows uniform parallel bilayer steps, and no morphological defects were noticeable over the entire epi-wafer.« less
  • The evolution of GaN growth on AlN and GaN nucleation layers is compared through morphological and structural analyses, including ion beam analysis. By using AlN nucleation layer grown at high temperature, improved crystalline quality is exhibited by 300 nm thin GaN epilayers. GaN (002) x-ray rocking curve as narrow as 168 arc sec and atomic-step surface morphology characterize such a thin GaN film on AlN. Defects are strongly confined into the first 50 nm of growth, whereas a fast laterally coherent growth is observed when increasing thickness, as an effect of high temperature AlN surface morphology and Ga adatom dynamicsmore » over this template.« less
  • We report growth of InGaN/GaN multi-quantum well (MQW) and LED structures on a novel composite substrate designed to eliminate the coefficient of thermal expansion (CTE) mismatch problems which impact GaN growth on bulk sapphire. To form the composite substrate, a thin sapphire layer is wafer-bonded to a polycrystalline aluminum nitride (P-AlN) support substrate. The sapphire layer provides the epitaxial template for the growth; however, the thermo-mechanical properties of the composite substrate are determined by the P-AlN. Using these substrates, thermal stresses associated with temperature changes during growth should be reduced an order of magnitude compared to films grown on bulkmore » sapphire, based on published CTE data. In order to test the suitability of the substrates for GaN LED growth, test structures were grown by metalorganic chemical vapor deposition (MOCVD) using standard process conditions for GaN growth on sapphire. Bulk sapphire substrates were included as control samples in all growth runs. In situ reflectance monitoring was used to compare the growth dynamics for the different substrates. The material quality of the films as judged by X-ray diffraction (XRD), photoluminescence and transmission electron microscopy (TEM) was similar for the composite substrate and the sapphire control samples. Electroluminescence was obtained from the LED structure grown on a P-AlN composite substrate, with a similar peak wavelength and peak width to the control samples. XRD and Raman spectroscopy results confirm that the residual strain in GaN films grown on the composite substrates is dramatically reduced compared to growth on bulk sapphire substrates.« less
  • AlGaN/GaN/AlN transistor structures were grown onto SiC substrates by molecular-beam epitaxy. Under aluminum-rich growth conditions for the AlN nucleation layer, undesirable n-type conduction is observed near the GaN/AlN interface for even thick (>1000 A) AlN layers. Silicon is identified as the unwanted dopant from secondary-ion mass spectroscopy measurements. Atomic force microscopy surface maps reveal free aluminum metal on AlN surfaces grown under modest aluminum-rich conditions. It is proposed that rapid silicon migration is caused by molten aluminum reacting with the SiC substrate resulting in dissolved silicon that rapidly migrates through the growing AlN layer. This behavior is significantly reduced usingmore » a growth flux ratio of aluminum to reactive nitrogen close to unity. The resulting buffer leakage current of the GaN high electron mobility transistor structure is reduced by more than four orders of magnitude.« less
  • This paper reports the growth by molecular beam epitaxy of AlN and GaN thin films on R-plane sapphire substrates. Contrary to previous findings that GaN grows with its (1120) A-plane parallel to the (1102) R-plane of sapphire, our results indicate that the crystallographic orientation of the III-nitride films is strongly dependent on the kinetic conditions of growth for the GaN or AlN buffer layers. Thus, group III-rich conditions for growth of either GaN or AlN buffers result in nitride films having (1120) planes parallel to the sapphire surface, and basal-plane stacking faults parallel to the growth direction. The growth ofmore » these buffers under N-rich conditions instead leads to nitride films with (1126) planes parallel to the sapphire surface, with inclined c-plane stacking faults that often terminate threading dislocations. Moreover, electron microscope observations indicate that slight miscut ({approx}0.5 deg. ) of the R-plane sapphire substrate almost completely suppresses the formation of twinning defects in the (1126) GaN films.« less