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Title: Density of defect states of aluminum nitride grown on silicon and silicon carbide substrates at room temperature

Abstract

Density of defect states of aluminum nitride (AlN) films deposited by rf magnetron sputtering on <100>-oriented silicon (Si) and 4H-silicon carbide (4H-SiC) have been investigated using the deep-level-transient-spectroscopy technique. The films were grown at room temperature with varying nitrogen flow from 4 to 20 sccm and a constant argon flow of 10 sccm. In general the defect densities of AlN are lower when grown on 4H-SiC substrates than on Si substrates. The observed defect levels are identified as donor-like triplet of nitrogen vacancy and DX-like centers. Defects located at 0.35-0.42 eV below the conduction band, attributed to dangling bonds of nitrogen atoms, are seen in samples grown with higher nitrogen flow rate. Shallow level defects, observed at approximately 0.1 eV below the conduction band, can be attributed to the recently discovered prismatic staking fault in the AlN atomic structure.

Authors:
; ;  [1]
  1. School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)
Publication Date:
OSTI Identifier:
20706490
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 87; Journal Issue: 24; Other Information: DOI: 10.1063/1.2140888; (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; ARGON; CRYSTAL GROWTH; DEEP LEVEL TRANSIENT SPECTROSCOPY; DEPOSITION; FLOW RATE; MILLI EV RANGE; NITROGEN; SEMICONDUCTOR MATERIALS; SILICON; SILICON CARBIDES; SPUTTERING; STACKING FAULTS; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; TRIPLETS; VACANCIES

Citation Formats

Ligatchev, V., Rusli,, and Pan Zhao. Density of defect states of aluminum nitride grown on silicon and silicon carbide substrates at room temperature. United States: N. p., 2005. Web. doi:10.1063/1.2140888.
Ligatchev, V., Rusli,, & Pan Zhao. Density of defect states of aluminum nitride grown on silicon and silicon carbide substrates at room temperature. United States. doi:10.1063/1.2140888.
Ligatchev, V., Rusli,, and Pan Zhao. Mon . "Density of defect states of aluminum nitride grown on silicon and silicon carbide substrates at room temperature". United States. doi:10.1063/1.2140888.
@article{osti_20706490,
title = {Density of defect states of aluminum nitride grown on silicon and silicon carbide substrates at room temperature},
author = {Ligatchev, V. and Rusli, and Pan Zhao},
abstractNote = {Density of defect states of aluminum nitride (AlN) films deposited by rf magnetron sputtering on <100>-oriented silicon (Si) and 4H-silicon carbide (4H-SiC) have been investigated using the deep-level-transient-spectroscopy technique. The films were grown at room temperature with varying nitrogen flow from 4 to 20 sccm and a constant argon flow of 10 sccm. In general the defect densities of AlN are lower when grown on 4H-SiC substrates than on Si substrates. The observed defect levels are identified as donor-like triplet of nitrogen vacancy and DX-like centers. Defects located at 0.35-0.42 eV below the conduction band, attributed to dangling bonds of nitrogen atoms, are seen in samples grown with higher nitrogen flow rate. Shallow level defects, observed at approximately 0.1 eV below the conduction band, can be attributed to the recently discovered prismatic staking fault in the AlN atomic structure.},
doi = {10.1063/1.2140888},
journal = {Applied Physics Letters},
number = 24,
volume = 87,
place = {United States},
year = {Mon Dec 12 00:00:00 EST 2005},
month = {Mon Dec 12 00:00:00 EST 2005}
}
  • AlN-SiC alloy crystals, with a thickness greater than 500 m, were grown on 4H- and 6H-SiC substrates from a mixture of AlN and SiC powders by the sublimation-recondensation method at 1860-1990 C. On-axis SiC substrates produced a rough surface covered with hexagonal grains, while 6H- and 4H- off-axis SiC substrates with different miscut angles (8? or 3.68?) formed a relatively smooth surface with terraces and steps. The substrate misorientation ensured that the AlN-SiC alloy crystals grew two dimensionally as identified by scanning electron microscopy (SEM). X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that the AlN-SiC alloys had themore » wurtzite structure. Electron probe microanalysis (EPMA) and x-ray photoelectron spectroscopy (XPS) demonstrated that the resultant alloy crystals had non-stoichiometric ratios of Al:N and Si:C and a uniform composition throughout the alloy crystal from the interface to the surface. The composition ratio of Al:Si of the alloy crystals changed with the growth temperature, and differed from the original source composition, which was consistent with the results predicted by thermodynamic calculation of the solid-vapor distribution of each element. XPS detected the bonding between Si-C, Si-N, Si-O for the Si 2p spectra. The dislocation density decreased with the growth, which was lower than 106 cm-2 at the alloy surface, more than two orders of magnitude lower compared to regions close to the crystal/substrate interface, as determined by TEM.« less
  • AlN-SiC alloy crystals, with a thickness greater than 500μm, were grown on 4H- and 6H-SiC substrates from a mixture of AlN and SiC powders by the sublimation-recondensation method at 1860-1990 C. On-axis SiC substrates produced a rough surface covered with hexagonal grains, while 6H- and 4H- off-axis SiC substrates with different miscut angles (8 or 3.68 ) formed a relatively smooth surface with terraces and steps. The substrate misorientation ensured that the AlNSiC alloy crystals grew two dimensionally as identified by scanning electron microscopy (SEM). Xray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that the AlN-SiC alloys had themore » wurtzite structure. Electron probe microanalysis (EPMA) and x-ray photoelectron spectroscopy (XPS) demonstrated that the resultant alloy crystals had non-stoichiometric ratios of Al:N and Si:C and a uniform composition throughout the alloy crystal from the interface to the surface. The composition ratio of Al:Si of the alloy crystals changed with the growth temperature, and differed from the original source composition, which was consistent with the results predicted by thermodynamic calculation of the solid-vapor distribution of each element. XPS detected the bonding between Si-C, Si-N, Si-O for the Si 2p spectra. The dislocation density decreased with the growth, which was lower than 10^6cm-2 at the alloy surface, more than two orders of magnitude lower compared to regions close to the crystal/substrate interface, as determined by TEM.« less
  • Solid solutions of aluminum nitride (AlN) and silicon carbide (SiC) have been grown at 900{endash}1300thinsp{degree}C on vicinal {alpha}(6H)-SiC(0001) substrates by plasma-assisted, gas-source molecular beam epitaxy. Under specific processing conditions, films of (AlN){sub x}(SiC){sub 1{minus}x} with 0.2{le}x{le}0.8, as determined by Auger electron spectrometry (AES), were deposited. Reflection high-energy electron diffraction (RHEED) was used to determine the crystalline quality, surface character, and epilayer polytype. Analysis of the resulting surfaces was also performed by scanning electron microscopy (SEM). High-resolution transmission electron microscopy (HRTEM) revealed that monocrystalline films with x{ge}0.25 had the wurtzite (2H) crystal structure; however, films with x{lt}0.25 had the zincblende (3C)more » crystal structure. {copyright} {ital 1998 Materials Research Society.}« less
  • Samples containing 50 mol% SiC and 50 mol% AIN were fabricated to near-theoretical density by hot-pressing in graphite dies in N/sub 2/ atmosphere. Grain size was varied by varying the hot-pressing conditions. Bar-shaped samples cut from the billets were subjected to creep deformation in four-point bending. Creep was found to depend upon the grain size with coarse-grained material exhibiting lower creep rate. The stress exponent was approx. =2.0.