共查询到20条相似文献,搜索用时 328 毫秒
1.
Investigation of the thermal conductivity of diamond film on aluminum nitride ceramic 总被引:1,自引:0,他引:1
Y. Liao R.C. Fang Z.Y. Ye N.G. Shang S.J. Han Q.Y. Shao S.Z. Ji 《Applied Physics A: Materials Science & Processing》1999,69(1):101-103
Diamond films were successfully synthesized on aluminum nitride(AlN) ceramic substrates by hot-filament chemical vapor deposition
(HFCVD) method. The thermal conductivity of the diamond film/aluminum nitride ceramic (DF/AlN) composites was studied by photothermal
deflection (PTD) technique. It has reached 2.04 W/cm K, 73% greater than that of AlN ceramic. Compared with the measurement
of scanning electron microscopy (SEM) and Raman spectroscopy, the influence of diamond films on the thermal conductivity of
the composites was pointed out. The adhesion and the stresses were also studied. The unusual stability and very good adhesion
of the diamond film on AlN ceramic substrate obtained is attributed to the formation of aluminum carbide.
Received: 24 March 1998 / Accepted: 8 March 1999 / Published online: 5 May 1999 相似文献
2.
J.-M. Liu N. Chong H.L.W. Chan K.H. Wong C.L. Choy 《Applied Physics A: Materials Science & Processing》2003,76(1):93-96
Epitaxial (001) aluminum nitride (AlN) thin films on (111) Si substrates are prepared using pulsed-laser deposition. The epitaxial
structure of the as-prepared thin films is characterized by checking the X-ray-diffraction θ-2 θ scan and pole-figure, using
scanning electron microscopy, infrared radiation (IR) spectroscopy and Raman spectroscopy. The surface acoustic-wave resonance
at 345 MHz for a 1.5 μm thick AlN film on a (111) Si substrate is observed using an inter-digital electrode.
Received: 18 September 2001 / Accepted: 29 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +86-25/359-5535, E-mail: liujm@nju.edu.cn 相似文献
3.
Lung-Chien Chen Ching-Ho Tien Wei-Chian Liao Yi-Min Luo 《Journal of luminescence》2011,131(6):1234-1238
This work presents an aluminum nitride (AlN) nanocolumnar layer sputtered at various oblique angles and its application as a buffer layer for GaN-based light-emitting diodes (LEDs) that are fabricated on sapphire substrates. The OA-AlN nanocolumnar layer has a diameter of about 30-60 nm. The GaN-based LED structure is perpendicularly extended from the OA-AlN nanocolumnar layer. Then, the nanocolumnar structure is merged into p-GaN layer to form a mesa structure with a diameter of about 200-600 nm on the surface of the GaN-based LED. Moreover, optical characteristics of the LED were studied using photoluminescence, along with the blue-shifts observed as well. 相似文献
4.
P. V. Seredin D. A. Goloschapov A. S. Lenshin V. E. Ternovaya I. N. Arsentyev A. D. Bondarev I. S. Tarasov 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(9):1119-1126
IR and UV spectroscopy is used to study the properties of nanostructured aluminum nitride films obtained via reactive ion-plasma sputtering on GaAs substrates with different orientations. Nanostructured thin (100–200 nm) films of cubic aluminum nitride with optical bandgaps of ~5 eV and refractive indices varying from 1.6 to 4.0 in the wavelength range of ~250 nm are fabricated. Growth on a misoriented GaAs(100) substrate (4° with respect to the [110] plane) makes it possible to synthesize AlN films with smaller grains and higher refractive indices (n ~ 4). It is shown that misoriented GaAs substrates allow us to control the morphology, surface composition, and optical functional characteristics of AlN/GaAs heterophase systems. 相似文献
5.
Nanocrystalline AlN thin films were prepared via DC sputtering technique at different substrate temperature. The crystal orientation
and particle size of aluminum nitride thin films were investigated by XRD analysis. Study indicated that the sample contained
pure phase hexagonal AlN nanoparticles with a single peak corresponding to the (100) planes. The peak at 665 cm−1 in the FTIR spectrum of film was assigned to the LO phonon of hexagonal AlN. The particle size of the film, prepared at substrate
temperature 200°C was about 9.5 nm, as investigated by atomic force microscope. Field emission study indicated that it can
be used as a good field emitter. Turn-on field (Eto) of 15.02 V/μm was observed for the AlN films synthesized at substrate temperature 200°C. Dielectric constant of the AlN
film was found nearly independent of frequencies in the measured frequency range 1 KHz to 1 MHz, i.e. in the audio frequency range. The values of dielectric constant (ε) were 10.07, 9.46 and 8.65 for the film prepared at 70°C, 150°C and 200°C, respectively, at frequency 1 KHz. 相似文献
6.
E. Sicard C. Boulmer-Leborgne C. Andreazza-Vignolle M. Frainais 《Applied Physics A: Materials Science & Processing》2001,73(1):55-60
The excimer laser nitriding process reported is developed to enhance the mechanical and chemical properties of aluminum alloys.
An excimer laser beam is focused onto the alloy surface in a cell containing 1-bar nitrogen gas. A vapor plasma expands from
the surface and a shock wave dissociates and ionizes nitrogen. It is assumed that nitrogen from plasma in contact with the
surface penetrates to some depth. Thus it is necessary to work with a sufficient laser fluence to create the plasma, but this
fluence must be limited to prevent laser-induced surface roughness. The nitrogen-concentration profiles are determined from
Rutherford backscattering spectroscopy and scanning electron microscopy coupled to energy-dispersive X-ray analysis. Crystalline
quality is evidenced by an X-ray diffraction technique. Transmission electron microscopy gives the in-depth microstructure.
Fretting coefficient measurements exhibit a lowering for some experimental conditions. The polycrystalline nitride layer obtained
is several micrometers thick and composed of a pure AlN (columnar microstructure) top layer (200–500 nm thick) standing on
an AlN (grains) in alloy diffusion layer. From the heat conduction equation calculation it is shown that a 308-nm laser wavelength
would be better to increase the nitride thickness, as it corresponds to a weaker reflectance R value for aluminum.
Received: 17 October 2000 / Accepted: 19 October 2000 / Published online: 23 May 2001 相似文献
7.
《Composite Interfaces》2013,20(8):723-735
The aluminum nitride (AlN) heterostructures were successfully grown on silicon substrate by plasma-assisted molecular beam epitaxy. The surface morphology and structural and optical properties of the sample have been investigated by reflection high electron diffraction, scanning electron microscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray, high-resolution X-ray diffraction (HR-XRD), Raman spectroscopy, and photoluminescence, respectively. HR-XRD measurement showed that the sample has a typical diffraction pattern of hexagonal AlN/GaN/AlN heterostructures. The Schottky characteristic of Pt contact on AlN/GaN/AlN heterostructures was also investigated under different annealing temperatures in nitrogen ambient. The temperature dependence and structural evolution of the Schottky barrier height (SBH) of Pt contacts were studied using the current–voltage measurement and FESEM, respectively. Our findings presented that the SBH of the samples change with different annealing temperatures. 相似文献
8.
《Current Applied Physics》2009,9(2):417-421
The penetration depth of electron in amorphous aluminum nitride (AlN) is determined in terms of energy loss per unit length using electron beam in a cathodoluminescence (CL) apparatus. Thin films bilayers of holmium doped aluminum nitride (AlN:Ho) and thulium doped aluminum nitride (AlN:Tm) are deposited on silicon substrates by rf magnetron sputtering method at liquid nitrogen temperatures. The bilayers structure consisted of a 37.8 nm thick AlN:Tm film on the top of a 15.3 nm thick AlN:Ho film. Electron beam of different energies are allowed to penetrate the AlN:Tm/AlN:Ho bilayers film. The spectroscopic properties of AlN:Ho and AlN:Tm, the thickness of the film and the energies of electron beam are used to calculate the penetration depth of electron in amorphous AlN. Electron beam of 2.5 keV energy was able to pass through the 37.8 nm thick AlN:Tm film. The electron penetration depth for AlN is found to be 661.4 MeV/cm. 相似文献
9.
Impact of step height of silicon carbide (SiC) substrates on heteroepitaxial growth of aluminum nitride (AlN) was investigated. Step-and-terrace structures with various step heights, 6 monolayer (ML), 3ML and 1ML, were formed on 6H-SiC (0 0 0 1) vicinal substrates by high-temperature gas etching. 2H-AlN layers were grown on the substrate by plasma-assisted molecular-beam epitaxy (MBE) and then these layers were characterized by atomic-force microscopy (AFM) and X-ray diffraction (XRD). High-quality AlN can be grown on SiC substrates with 6ML- and 3ML-height step, while AlN grown on SiC substrates with 1ML-height step exhibited inferior crystalline quality. A model for high-quality AlN growth on SiC substrates with 3ML-height step is proposed. 相似文献
10.
Y. Liu T. P. Chen M. Yang Z. H. Cen X. B. Chen Y. B. Li S. Fung 《Applied Physics A: Materials Science & Processing》2009,95(3):753-756
Electroluminescence (EL) from Al-rich AlN thin films grown on p-type Si substrate by radio frequency (RF) magnetron sputtering
has been observed at room temperature. The light-emitting structure based on the thin films can be driven by an electrical
pulse as short as 10−5 s. No obvious change in the light emission intensity was observed after 106 pulse cycles. It has been found that the light emission intensity increases with the Al concentration. It is shown that the
phenomenon is due to the enhancement of the percolative conduction via the Al nanocrystals distributed in the AlN matrix as
a result of the increase in Al concentration. 相似文献
11.
Deposition of aluminum nitride thin film on Si(1 1 1) by KrF excimer laser and its characterizations
We present the deposition of aluminum nitride (AlN) thin film by KrF excimer laser sputtering and the study of the effects of substrate temperature and laser fluences. Deposition rate of AlN thin film at 0.3 Å/pulse has been achieved with laser fluence of 1500 mJ/cm2 and at substrate temperature of 250 K, and this shows the enhancement of the deposition rate at low substrate temperature. Surface morphology of the deposited films is characterized by atomic force microscopy (AFM). In addition, the electrical performance of the MIS devices with AlN thin films prepared in this experiment has been characterized. 相似文献
12.
《Applied Surface Science》2005,239(3-4):327-334
The application of silicon-on-insulator (SOI) substrates to high-power integrated circuits is hampered by the self-heating effect due to the poor thermal conductivity of the buried SiO2 layer. We introduce aluminum nitride (AlN) thin films formed by ultra-high vacuum electron-beam evaporation with ammonia as an alternative. The chemical composition, surface morphology, and electrical properties of these films were investigated. The film synthesized at 800 °C shows a high AlN content, low surface roughness with a root-mean-square value of 0.46 nm, and high electrical resistivity. Based on thermodynamic analysis and our experimental results, the mechanism of AlN formation is proposed. 相似文献
13.
Preferentially-oriented aluminum nitride (AlN) films are grown directly on natively-oxidized Si (100) substrate by pulsed laser deposition (PLD) in nitrogen (N2) environment. The AlN preferential orientation changes from (002) to (100) with increasing N2 pressure. Such different behaviors are discussed in terms of deposition-rate-dependent preferential orientation, kinetic energy of depositing species and confinement of laser plume. Finally, sample deposited at 0.9 Pa is proved to have the highest (002) peak intensity, the lowest FWHM value, the highest deposition rate and a relatively low RMS roughness (1.138 nm), showing the optimal growth condition for c-axis-oriented AlN growth at this N2 pressure. 相似文献
14.
《中国光学快报(英文版)》2019,(11)
In this work, Er-doped aluminum nitride(AlN), Pr-doped AlN, and Er, Pr co-doped AlN thin films were prepared by ion implantation. After annealing, the luminescence properties were investigated by cathodoluminescence. Some new and interesting phenomena were observed. The peak at 480 nm was observed only for Er-doped AlN. However, for Er, Pr co-doped AlN, it disappeared. At the same time, a new peak at 494 nm was observed,although it was not observed for Er-doped AlN or Pr-doped AlN before. Therefore, the energy transfer mechanism between Er~(3+)and Pr~(3+)in AlN thin films was investigated in detail. Through optimizing the dose ratio of Er~(3+)with respect to Pr~(3+), white light emission with an International Commission on Illumination chromaticity coordinate(0.332, 0.332) was obtained. This work may provide a new strategy for realizing white light emission based on nitride semiconductors. 相似文献
15.
Y.W. Goh Y.F. Lu Z.M. Ren T.C. Chong 《Applied Physics A: Materials Science & Processing》2003,77(3-4):433-439
Aluminium nitride (AlN) thin films have been grown on Si(100), Si(111) and Sapphire Al2O3(001) substrates by pulsed KrF excimer laser (wavelength 248 nm, duration 30 ns) ablation of an AlN target with the assistance of nitrogen-ion-beam bombardment. The influence of process parameters such as substrate temperature and ion-beam energy has been investigated in order to obtain high-quality AlN films. The AlN films deposited by pulsed-laser deposition (PLD) have been characterized by X-ray diffraction (XRD) to determine the crystalline quality, grain size and growth orientation with respect to the substrate. The XRD spectra of AlN films on Si(100), Si(111) and Sapphire substrates yield full-width-half-maximum (FWHM) values of approximately 1.6. The bonding characteristics in the films have been evaluated by Raman spectroscopy. The chemical composition of the films has been characterized by X-ray photoelectron spectroscopy (XPS). The surface morphology of the films has been measured by atomic force microscopy (AFM). At a substrate temperature of at least 600 °C, polycrystalline AlN films with orientations of AlN(100) and AlN(101) have been synthesized. PACS 68.55.-a; 81.15.Fg; 77.84.Bw 相似文献
16.
Structural and optical properties of RF magnetron sputtered aluminum nitride films without external substrate heating 总被引:1,自引:0,他引:1
Atul Vir Singh Sudhir ChandraA.K. Srivastava B.R. ChakrobortyG. Sehgal M.K. DalaiG. Bose 《Applied Surface Science》2011,257(22):9568-9573
We report structural and optical properties of aluminum nitride (AlN) thin films prepared by RF magnetron sputtering. A ceramic AlN target was used to sputter deposit AlN films without external substrate heating in Ar-N2 (1:1) ambient. The X-ray diffraction and high resolution transmission electron microscopy results revealed that the films were preferentially oriented along c-axis. Cross-sectional imaging revealed columnar growth perpendicular to the substrate. The secondary ion mass spectroscopy analysis confirmed that aluminum and nitrogen distribution was uniform within the thickness of the film. The optical band gap of 5.3 eV was evaluated by UV-vis spectroscopy. Photo-luminescence broad band was observed in the range of 420-600 nm with two maxima, centered at 433 nm and 466 nm wavelengths related to the energy states originated during the film growth. A structural property correlation has been carried out to explore the possible application of such important well oriented nano-structured two-dimensional semiconducting objects. 相似文献
17.
《Composite Interfaces》2013,20(4):243-256
The thermal conductivity of boron nitride and aluminum nitride particle epoxy-matrix composites was increased by up to 97% by surface treatment of the particles prior to composite fabrication. The increase in thermal conductivity is due to decrease in the filler-matrix thermal contact resistance through the improvement of the interface between matrix and particles. Effective treatments for BN involved acetone, acids (nitric and sulfuric) and silane. The most effective treatment involved silane such that the coating resulted from the treatment amounted to 2.4% of the weight of the treated BN. The effectiveness of a treatment was higher for a larger BN volume fraction. At 57 vol.% BN, the thermal conductivity reached 10.3 W/ m·K. The treatments had little effect on the specific surface area of the BN particles. Silane treatments were also effective for AlN. At 60 vol.% AlN, the thermal conductivity reached 11.0 W/m·K. 相似文献
18.
G.F. Iriarte D.F. ReyesD. González J.G. RodriguezR. García F. Calle 《Applied Surface Science》2011,257(22):9306-9313
A pulsed DC reactive ion beam sputtering system has been used to synthesize aluminium nitride (AlN) thin films at room temperature by reactive sputtering. After systematic study of the processing variables, high-quality polycrystalline films with preferred c-axis orientation have been grown successfully on silicon and Au/Si substrates with an Al target under a N2/(N2 + Ar) gas flow ratio of 55%, 2 mTorr processing pressure and keeping the temperature of the substrate holder at room temperature. The crystalline quality of the AlN layer as well as the influence of the substrate crystallography on the AlN orientation has been characterized by high-resolution X-ray diffraction (HR-XRD). Best ω-FWHM (Full Width at Half Maximum) values of the (0 0 0 2) reflection rocking curve in the 1 μm thick AlN layers are 1.3°. Atomic Force Microscopy (AFM) measurements have been used to study the surface morphology of the AlN layer and Transmission Electron Microscopy (TEM) measurements to investigate the AlN/substrate interaction. AlN grew off-axis from the Si substrate but on-axis to the surface normal. When the AlN thin film is deposited on top of an Au layer, it grows along the [0 0 0 1] direction but showing a two-domain structure with two in-plane orientations rotated 30° between them. 相似文献
19.
J. Sun J.D. Wu Z.F. Ying W. Shi Z.Y. Zhou K.L. Wang X.M. Ding F.M. Li 《Applied Physics A: Materials Science & Processing》2001,73(1):91-95
Combination of pulsed laser ablation with electron cyclotron resonance microwave discharge was demonstrated for a novel method
for low-temperature thin film growth. Aluminum nitride thin films were synthesized on silicon substrates at temperatures below
80 °C by means of reactive pulsed laser deposition in nitrogen plasma generated from the electron cyclotron resonance discharge.
The synthesized films show a very smooth surface and were found to have a stoichiometric AlN composition. X-ray photoelectron
spectroscopy analysis evidenced the formation of aluminum nitride compound. Fourier transform infrared spectroscopy revealed
the characteristic phonon modes of AlN. The AlN films were observed to be highly transparent in the visible and near-IR regions
and have a sharp absorption edge near 190 nm. The band gap of the synthesized AlN films was determined to be 5.7 eV. The mechanisms
responsible for the low-temperature film synthesis are also discussed in the paper. The nitrogen plasma facilitates the nitride
formation and enhances the film growth.
Received: 17 March 2000 / Accepted: 28 March 2000 / Published online: 23 May 2001 相似文献
20.
J.P. Kar S.N. DasJ.H. Choi T.I. LeeJ. Seo T. LeeJ.M. Myoung 《Applied Surface Science》2011,257(11):4973-4977
Vertically aligned, c-axis oriented zinc oxide (ZnO) nanowires were grown on Si substrate by metal organic chemical vapor deposition (MOCVD) technique, where sputtered aluminum nitride (AlN) film was used as an intermediate layer and thermally evaporated barium fluoride (BaF2) film as a sacrificial layer. The aspect ratio and density of the nanowires were also varied using only Si microcavity without any interfacial or sacrificial layer. The UV detectors inside the microcavity have shown the higher on-off current ratio and fast photoresponse characteristics. The photoresponse characteristics were significantly varied with the aspect ratio and the density of nanowires. 相似文献