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AlN Films (aln + film)

Distribution by Scientific Domains

Physics and Astronomy	85%
Polymers and Materials Science	14%

Selected Abstracts

Electrical Properties of MIS Capacitors with AlN Films Synthesized by Pulsed Laser Deposition

PLASMA PROCESSES AND POLYMERS, Issue 2 2006
Silvia Bakalova
Abstract Summary: We manufactured for the first time MIS capacitors based on aluminium nitride (AlN) thin films synthesized by Pulsed Laser Deposition (PLD). AlN films were deposited on Si substrates by PLD from AlN targets in nitrogen ambient by multi-pulse ablation using a UV KrF excimer laser source (,,=,248 nm, ,,=,7 ns). The structures we prepared were electrically characterized by C-V and I-V complementary measurements. Our studies evidence the formation of good interfaces, and of defects into the film bulk which are electrically active. This justifies further developments in view of future applications of PLD synthesized AlN thin films as a dielectric alternatives to SiO2. The distribution of the interface trap densities (Dit) in Si bandgap for AlN/Si structures synthesized at different N2 pressures. [source]

Low-temperature growth of high quality AlN films on carbon face 6H-SiC

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 1 2008
Myunghee Kim
Abstract AlN films have been grown on atomically flat carbon face 6H-SiC (000) substrates by pulsed laser deposition and their structural properties have been investigated. In-situ reflection high-energy electron diffraction observations have revealed that growth of AlN at 710 °C proceeds in a Stranski,Krastanov mode, while typical layer-by-layer growth occurs at room temperature (RT) with atomically flat surfaces. It has been revealed that the crystalline quality of the AlN film is dramatically improved by the reduction in growth temperature down to RT and the full width at half maximum values in the X-ray rocking curves for 0004 and 102 diffractions of the RT-grown AlN film are 0.05° and 0.07°, respectively. X-ray reciprocal space mapping has revealed that the introduction of misfit dislocations is suppressed in the case of RT growth, which is probably responsible for the improvement in crystalline quality. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

MOVPE high quality GaN film grown on Si (111) substrates using a multilayer AlN buffer

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008
Kung-Liang Lin
Abstract High quality GaN films were successfully grown on Si (111) substrates using the MOVPE method and a multilayer AlN buffer. The buffer layer film quality and thickness are critical for the growth of the crack-free GaN film on Si (111) substrates. Cracks started to form on the single layer high temperature (HT) AlN film grown on Si (111) substrate as the AlN thickness was greater than 20 nm. However, a 100 nm crack-free AlN film can be obtained when multilayer buffer of HT-AlN/low temperature (LT)-AlN/HT-AlN was grown on the Si (111) substrate. By using multilayer AlN buffer, a 2 ,m crack-free GaN film was successful grown on the 2" Si (111) substrate. Moreover, the GaN film (2,m thick) grown on Si with a GaN (004) Mosaic FWHM of only 0.12°. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

High temperature growth of AlN film by LP-HVPE

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007
K. Tsujisawa
Abstract AlN films were grown on AlN/sapphire templates at 1400,1500 °C using low-pressure hydride vapor phase epitaxy (LP-HVPE). Compared to the step-flow growth of AlN film at 1200 °C with growth rate of 2.1 ,m/h, AlN films with atomic steps were obtained at 1400,1500 °C even with high growth rate. For the AlN film grown at 1450 °C with growth rate of 14.3 ,m/h, the RMS value is 0.75 nm and the FWHM values of (0002) and (10-12) X-ray rocking curve (XRC) are 351 and 781 arcsec, respectively. Since the FWHM value of (10-12) XRC for the AlN/sapphire template is 1492 arcsec, the crystal quality of HVPE-grown AlN is greatly improved compared with the AlN/sapphire template, which is also confirmed by TEM observation. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Fabrication of thick AlN film by low pressure hydride vapor phase epitaxy

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006
Yu-Huai Liu
Abstract Thick AlN crystals were grown by conventional hydride vapor phase epitaxy (HVPE) on AlN/sapphire templates under low pressure (,15 Torr) at high temperature (1100 °C,1200 °C). Colorless, mirror-like AlN films were obtained at the growth rates of up to 20.6 ,m/h. The best root mean square (RMS) value of atomic force microscope (AFM) observations for the AlN surface was 0.19 nm in a surface of 5×5 ,m2. The typical values of full width half maximum (FWHM) of X-ray rocking curves for (0002) and (102) diffraction of AlN films were 173,314 arcsec and 1574,1905 arcsec, respectively. We also investigated the influences of carrier gas, growth temperature and growth rate on the crystal quality. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Analysis of the local structure of AlN:Mn using X-ray absorption fine structure measurements

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006
Takao Miyajima
Abstract The local structure around the Mn atoms in MOCVD-grown AlN:Mn films which show Mn-related red-orange photoluminescence with a 600nm-peak at room temperature was investigated using the X-ray absorption fine structure (XAFS) measurements. We found that Mn atoms occupy Al lattice sites in the AlN film and that the Mn ions have a charge between +2 and +3. From these results, we think that the red-orange luminescence is caused by the transition of d-electrons in the Mn ions. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Ultra-flat and high-quality AlN thin films on sapphire (0001) substrates grown by rf-MBE

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003
X. Q. Shen
Abstract AlN films on sapphire (0001) substrates grown by plasma-assisted molecular beam epitaxy are investigated. In-situ reflection high-energy electron diffraction shows a streak pattern from the beginning of the AlN growth indicating the 2-dimensional (2D) growth mode of AlN. High-resolution X-ray diffraction measurements illustrate that the full-width at half maximum of AlN (0002) peak is less than 80 arcsec when the thickness of AlN is more than 200 nm showing high structural film quality. Clear near-band edge emission at 77 K is observed from an 800 nm-thick AlN film by cathodoluminescence measurements. Atomic force microscopy observations show ultra-flat surface morphologies of AlN with rms as small as 0.12 nm. All characterization results suggest the high-quality of AlN films. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Preparation of Oriented Aluminum Nitride Thin Films on Polyimide Films and Piezoelectric Response with High Thermal Stability and Flexibility

ADVANCED FUNCTIONAL MATERIALS, Issue 3 2007
M. Akiyama
Abstract c -Axis oriented aluminum nitride (AlN) thin films are successfully prepared on amorphous polyimide films by radiofrequency magnetron reactive sputtering at room temperature. Structural analysis shows that the AlN films have a wurtzite structure and consist of c -axis oriented columnar grains about 100,nm wide. The full width at half maximum of the X-ray diffraction rocking curves and piezoelectric coefficient d33 of the AlN films are 8.3° and 0.56,pC,N,1, respectively. The AlN films exhibit a piezoelectric response over a wide temperature range, from ,196 to 300,°C, and can measure pressure within a wide range, from pulse waves of hundreds of pascals to 40,MPa. Moreover, the sensitivity of the AlN films increases with the number of times it was folded, suggesting that we can control the sensitivity of the AlN films by changing the geometric form. These results were achieved by a combination of preparing the oriented AlN thin films on polyimide films, and sandwiching the AlN and polymer films between top and bottom electrodes, such as Pt/AlN/polyimide/Pt. They are thin (less than 10,,m), self powered, adaptable to complex contours, and available in a variety of configurations. Although AlN is a piezoelectric ceramic, the AlN films are flexible and excellent in mechanical shock resistance. [source]

Low-temperature growth of high quality AlN films on carbon face 6H-SiC

First principles study of the decomposition processes of AlN in a hydrogen atmosphere

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2008
U. Panyukova
Abstract The growth of AlN films by the hydrogen vapor phase epitaxy method is generally carried out at a high temperature over a hydrogen atmosphere. The difficulties concerned with the decomposition processes on the surface during the film growth result in necessity of computer modelling of that processes. First principles calculations of the decomposition processes of AlN in a hydrogen atmosphere are reported. The mechanism of desorption of atoms from the surface was determined. Al atoms desorb as AlH from (0001) surface and as Al from (000-1) surface of AlN. And N atoms desorb as NH3 from (0001) surface and as NH from (000-1) surface of AlN. The desorption of Al atoms is a rate limiting reaction. The calculation results correspond well with the experimental date published earlier. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Fully unstrained GaN on sacrificial AlN layers by nano-heteroepitaxy

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007
K. Tonisch
Abstract Usually, the fabrication of microelectromechanical systems (MEMS) requires unstrained or tensile strained active layers on a selectively removable sacrificial layer, since compressive strain causes instabilities due to buckling effects. For group III-nitride based MEMS, AlN is a promising material for sacrificial layers since it can be epitaxially overgrown and etched selectively to GaN. However, due to the larger lattice constants GaN is growing compressively strained on AlN. Nanoheteroepitaxy opens a way to yield fully unstrained, high quality epitaxial GaN layers on nanocrystalline AlN thin film by means of a 3D strain relaxation mechanism. For this purpose sputtered nanocrystalline AlN films were overgrown with single crystalline GaN and AlGaN/GaN layers by metalorganic chemical vapor deposition. The high quality of the layers is proven by an atomically flat surface and a 2D electron gas at the interface of the AlGaN/GaN heterostructure (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

High temperature growth of AlN film by LP-HVPE

Fabrication of thick AlN film by low pressure hydride vapor phase epitaxy

GaN/AlN super-lattice structures on vicinal sapphire (0001) substrates grown by rf-MBE

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2005
X.Q. Shen
Abstract GaN/AlN super-lattice structures (SLs) grown on the vicinal sapphire (0001) substrates by rf-MBE are investigated using various characterization techniques. The satellite XRD diffraction peaks originating from the SLs are clearly observed, which indicate an abrupt interface and good periodicity of the SLs. Cross-sectional TEM observations show differnet features of SLs grown on the various vicinal substrates, depending on whether macro-steps form on the surface or not. DUV-Raman measurements show unique spectra from the SLs, which are different from the usual GaN and AlN films. The usage of a proper vicinal substrate angle shows a great merit to obtain high quality GaN/AlN SLs. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]