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1.
R. D. Dupuis C. J. Eiting P. A. Grudowski H. Hsia Z. Tang D. Becher H. Kuo G. E. Stillman M. Feng 《Journal of Electronic Materials》1999,28(3):319-324
Ion implantation into III–V nitride materials is animportant technology for high-power and high-temperature digital and monolithic
microwave integrated circuits. We report the results of the electrical, optical, and surface morphology of Si ion-implanted
GaN films using furnace annealing. We demonstrate high sheet-carrier densities for relatively low-dose (natoms=5×1014 cm−2) Si implants into AlN/GaN/sapphire heteroepitaxial films. The samples that were annealed at 1150°C in N2 for 5 min exhibited a smooth surface morphology and a sheet electron concentration ns ∼9.0×1013 cm−2, corresponding to an estimated 19% electrical activation and a 38% Si donor activation in GaN films grown on sapphire substrates.
Variable-temperature Hall-effect measurem entsindicate a Si donor ionization energy ∼15 meV. 相似文献
2.
Mg- and Si-doped GaN and AlGaN films were grown by metalorganic chemical vapor deposition and characterized by room-temperature
photoluminescence and Hall-effect measurements. We show that the p-type carrier concentration resulting from Mg incorporation
in GaN:Mg films exhibits a nonlinear dependence both on growth temperature and growth pressure. For GaN and AlGaN, n-type
doping due to Si incorporation was found to be a linear function of the silane molar flow. Mg-doped GaN layers with 300K hole
concentrations p ∼2×1018 cm−3 and Si-doped GaN films with electron concentrations n∼1×1019 cm−3 have been grown. N-type Al0.10Ga0.90N:Si films with resistivities as low as p ∼6.6×10−3 Ω-cm have been measured. 相似文献
3.
Jarod C. Gagnon Mihir Tungare Xiaojun Weng Jeffrey M. Leathersich Fatemeh Shahedipour-Sandvik Joan M. Redwing 《Journal of Electronic Materials》2012,41(5):865-872
In situ wafer curvature measurements were used in combination with postgrowth structural characterization to study the evolution
of film stress and microstructure in GaN layers grown by metalorganic chemical vapor deposition on N+ ion-implanted AlN/Si (111) substrates. The results were compared with growth on identical unimplanted substrates. In situ stress measurements revealed that, for the unimplanted sample, the GaN initiated growth under compressive stress of −1.41 GPa
which arose due to lattice mismatch with the AlN buffer layer. In contrast, GaN growth on the ion-implanted sample began at
lower compressive stress of −0.84 GPa, suggesting a reduction in epitaxial stress. In both cases, the compressive growth stress
was fully relaxed after ~0.7 μm and minimal tensile stress was generated during growth. During post-growth cooling, tensile stress was introduced in the
GaN layer of both samples due to thermal expansion mismatch. Post-growth optical microscopy characterization, however, demonstrated
that the ion-implanted sample had lower density of channeling cracks compared with the unimplanted sample. Cross-sectional
transmission electron microscopy images of the sample grown on ion-implanted Si with no post-implantation nitrogen annealing
revealed the formation of horizontal cracks in the implanted region beneath the AlN buffer layer. The weakened layer acts
to decouple the GaN film from the Si substrate and thereby reduces the density of channeling cracks in the film after growth. 相似文献
4.
We have fabricated high-quality <001> textured Pb(Zr0.54Ti0.46)O3 (PZT) thin films on (00l)Si with interposing <001> textured YBa2Cu3O7−δ (YBCO) and yttria-stabilized zirconia (YSZ) buffer layers using pulsed laser deposition (KrF excimer laser, λ, = 248 nm,
τ = 20 nanosecs). The YBCO layer provides a seed for PZT growth and can also act as an electrode for the PZT films, whereas
YSZ provides a diffusion barrier as well as a seed for the growth of YBCO films on (001)Si. These heterostructures were characterized
using x-ray diffraction, high-resolution transmission electron microscopy, and Rutherford backscattering techniques. The YSZ
films were deposited in oxygen ambient (∼9 × 10−4 Torr) at 775°C on (001)Si substrate having <001>YSZ // <001>Si texture. The YBCO thin films were deposited in-situ in oxygen
ambient (200 mTorr) at 650°C. The temperature and oxygen ambient for the PZT deposition were optimized to be 530°C and 0.4-0.6
Torr, respectively. The laser fluence to deposit this multilayer structure was 2.5-5.0 J/cm2. The <001> textured perovskite PZT films showed a dielectric constant of 800-1000, a saturation polarization of 37.81 μC/cm2, remnant polarization of 24.38 μC/cm2 and a coercive field of 125 kV/cm. The effects of processing parameters on microstructure and ferroelectric properties of
PZT films and device implications of these structures are discussed. 相似文献
5.
The authors have demonstrated photochemical deposition of aluminum oxides from Trimethylaluminum (TMA) and N2O by using a pulsed ArF excimer laser (193 nm). Both TMA and N2O are efficiently photodissociated by the 193 nm light. The films are grown on Si and InP wafers contained in a low pressure
flowing cell with a heated substrate. The incident laser beam is focused and parallel to the substrate surface. Typical deposition
rates are 80–150 A/min. Stripes of aluminum oxide 30 mm wide are uniformly grown on 7.5 cm Si-wafers. The film composition
and purity have been investigated using Auger and Infra-red spectroscopy analysis. Surprising results are the relatively low
concentration of carbon. Refractive index and thickness have been determined by an ellipsometer. Typical values for the films
are 1.54–1.62. Metal-oxide-semiconductor capacitors have been fabricated and characterized. The C-V curves for n-InP/aluminum
oxide have clockwise hysteresis, and minimum loop width is less than 0.5 V. The surface state densities are 1 × 1011 cm-2 eV−1 at the mid band gap. 相似文献
6.
A. D. Hanser C. A. Wolden W. G. Perry T. Zheleva E. P. Carlson A. D. Banks R. J. Therrien R. F. Davis 《Journal of Electronic Materials》1998,27(4):238-245
The influence of diluent gas on the metalorganic vapor phase epitaxy of AlN and GaN thin films has been investigated. A computational
fluid dynamics model using the finite element method was employed to improve film uniformity and to analyze transport phenomena.
The properties of AlN and GaN thin films grown on α(6H)-SiC(0001) substrates in H2 and N2 diluent gas environments were evaluated. Thin films of AlN grown in H2 and N2 had root mean square (rms) roughness values of 1.5 and 1.8 nm, respectively. The surface and defect microstructures of the
GaN thin films, observed by scanning and transmission electron microscopy, respectively, were very similar for both diluents.
Low temperature (12K) photoluminescence measurements of GaN films grown in N2 had peak intensities and full widths at half maximum equal to or better than those films grown in H2. A room temperature Hall mobility of 275 cm2/V·s was measured on 1 μm thick, Si-doped, n-type (1×1017 cm−3) GaN films grown in N2. Acceptor-type behavior of Mg-doped GaN films deposited in N2 was repeatably obtained without post-growth annealing, in contrast to similar films grown in H2. The GaN growth rates were ∼30% higher when H2 was used as the diluent. The measured differences in the growth rates of AlN and GaN films in H2 and N2 was attributed to the different transport properties of these mixtures, and agreed well with the computer model predictions.
Nitrogen is shown to be a feasible alternative diluent to hydrogen for the growth of AlN and GaN thin films. 相似文献
7.
Room-temperature ferromagnetic ordering in Mn-doped ZnO thin films grown by pulsed laser deposition 总被引:1,自引:0,他引:1
W. Y. Shim K. A. Jeon K. I. Lee S. Y. Lee M. H. Jung W. Y. Lee 《Journal of Electronic Materials》2006,35(4):635-640
The ferromagnetic ordering in Mn-doped ZnO thin films grown by pulsed laser deposition (PLD) as a function of oxygen pressure
and substrate temperature has been investigated. Room-temperature ferromagnetic behaviors in the Mn-doped ZnO films grown
at 700°C and 800°C under 10−1 torr in oxygen pressure were found, whereas ferromagnetic ordering in the films grown under 10−3 torr disappeared at 300 K. The large positive magnetoresistance (MR), ∼10%, was observed at 5 K at low fields and small negative
MR was observed at high fields, irrespective of oxygen pressure. In particular, anomalous Hall effect (AHE) in the Mn-doped
ZnO film grown at 700°C under 10−1 Torr has been observed up to 210 K. In this work, the observed AHE is believed to be further direct evidence demonstrating
that the Mn-doped ZnO thin films are ferromagnetic. 相似文献
8.
P. Tiwari X. D. Wu S. R. Foltyn I. H. Campbell Q. X. Jia R. E. Muenchausen D. E. Peterson T. E. Mitchell 《Journal of Electronic Materials》1996,25(1):51-55
Highly crystalline SrRuO3 (SRO) and La0.5Sr0.5CoO3 (LSCO) thin films were deposited on (100) Pt/ MgO by pulsed laser deposition. The films were mainly (001) textured normal
to the substrate surface with a high degree of in-plane orientation with respect to the substrate’s major axes. These films
were characterized using x-ray diffraction, Rutherford backscattering, four-point probe resistivity measurement, and transmission
electron microscopy. The room temperature resistivity for LSCO and SRO films on Pt/MgO was found to be ∼35 and ∼40 μΩ-cm,
respectively. An ion beam minimum channeling yield of ∼43% and ∼33% was obtained for LSCO and SRO films, respectively. The
interface between Pt and oxide was found to be smooth and free from any interfacial diffusion. This result showed that high-quality
low resistivity oxide thin films can be deposited on Pt. 相似文献
9.
V. Yu. Rud’ V. F. Gremenok Yu. V. Rud’ R. N. Bekimbetov I. V. Bodnar’ 《Semiconductors》1999,33(10):1097-1099
AgInSe2 thin films on glass substrates have been prepared by pulsed laser deposition. Rectifying heterojunctions with a pronounced
photovoltaic effect have been fabricated for the first time by placing such films in optical contact with layered III-VI (InSe,
GaSe) semiconductors. The maximum photosensitivity of such heterostructures is 10–103 V/W. It is concluded that the prepared structures can be used as wideband selective photoreceivers.
Fiz. Tekh. Poluprovodn. 33, 1205–1208 (October 1999) 相似文献
10.
Z.X. Zhang X.J. Pan T. Wang L. Jia L.X. Liu W.B. Wang E.Q. Xie 《Journal of Electronic Materials》2008,37(8):1049-1053
Nanocrystalline GaN films were prepared by thermal treatment of amorphous GaN films under flowing NH3 at a temperature of 600°C to 950°C for 1 h to 2 h. X-ray diffraction and field-emission scanning electron microscopy confirmed
the formation of high-crystal-quality hexagonal GaN films with preferential (002) orientation. The photoluminescence spectrum
showed a sharp peak near the band gap emission located at 368 nm and a broad blue peak centered at 430 nm. Five first-order
Raman modes near ∼143 cm−1, 535 cm−1, 555 cm−1, 568 cm−1, and 731 cm−1 with two new additional Raman peaks at 257 cm−1 and 423 cm−1 were observed. The origin of these new Raman peaks is discussed briefly. 相似文献
11.
M. D. Bremser W. G. Perry O. H. Nam D. P. Griffis R. Loesing D. A. Ricks R. F. Davis 《Journal of Electronic Materials》1998,27(4):229-232
Thin films of Si-doped AlxGa1−xN (0.03≤x≤0.58) having smooth surfaces and strong near-band edge cathodoluminescence were deposited at 0.35–0.5 μm/h on on-axis
6H-SiC(0001) substrates at 1100°C using a 0.1 μm AlN buffer layer for electrical isolation. Alloy films having the compositions
of Al0.08Ga0.92N and Al0.48Ga0.52N exhibited mobilities of 110 and 14 cm2/V·s at carrier concentrations of 9.6×1018 and 5.0×1017 cm−3, respectively. This marked change was due primarily to charge scattering as a result of the increasing Al concentration in
these random alloys. Comparably doped GaN films grown under similar conditions had mobilities between 170 and ∼350 cm2/V·s. Acceptor doping of AlxGa1−xN for x≤0.13 was achieved for films deposited at 1100°C. No correlation between the O concentration and p-type electrical
behavior was observed. 相似文献
12.
S. T. Kim Y. J. Lee D. C. Moon C. Lee H. Y. Park 《Journal of Electronic Materials》1998,27(10):1112-1116
A hydride vapor phase epitaxy was employed to grow the 10∼240 μm thick GaN films on a (111) MgAl2O4 substrate. The GaN films on a MgAl2O4 substrate revealed characteristics of photoluminescence (PL) in impurity doped GaN, which may be due to the out-diffusion
and auto-doping of Mg from the MgAl2O4 substrate during GaN growth. The PL peak energy of neutral donor bound exciton emission and the frequency of Raman E2 mode were decreased by increasing the GaN thickness, due to the residual strain relaxation in the epilayers. The dependence
of Raman E2 mode of GaN films on residual strain can be estimated as Δ ω/Δ σ=3.93 (cm−1/GPa). 相似文献
13.
Effect of AlN buffer layer thickness on the properties of GaN films grown by pulsed laser deposition
The GaN films are grown by pulsed laser deposition (PLD) on sapphire, AlN(30 nm)/Al2O3 and AlN(150 nm)/Al2O3, respectively. The effect of AlN buffer layer thickness on the properties of GaN films grown by PLD is investigated systematically. The characterizations reveal that as AlN buffer layer thickness increases, the surface root-mean-square (RMS) roughness of GaN film decreases from 11.5 nm to 2.3 nm, while the FWHM value of GaN film rises up from 20.28 arcmin to 84.6 arcmin and then drops to 31.8 arcmin. These results are different from the GaN films deposited by metal organic chemical vapor deposition (MOCVD) with AlN buffer layers, which shows the improvement of crystalline qualities and surface morphologies with the thickening of AlN buffer layer. The mechanism of the effect of AlN buffer layer on the growth of GaN films by PLD is hence proposed. 相似文献
14.
As a first step towards developing heterostructures such as GaAs/Ge/Si entirely by chemical vapor deposition, Ge films have
been deposited on (100) Si by the pyrolysis of GeH4. The best films are grown at 700° C and are planar and specular, with RBS minimum channeling yields of ≈4.0% (near the theoretical
value) and defect densities of 1.3 x 108 cm−2. Variations of in-situ cleaning conditions, which affect the nature of the Si substrate surface, greatly affect the ability
to get good epitaxial growth at 700° C. The majority of the defects found in the Ge films are extrinsic stacking faults, formed
by dissociation of misfit and thermal expansion accommodation dislocations. The stacking fault density is not significantly
reduced by post-deposition annealing, as is the case for the dislocations observed in MBE Ge films. It is suggested that lowering
the CVD growth temperature through the use of high vacuum deposition equipment would result in dislocation defects like those
of MBE films which could then be annealed more effectively than stacking faults. Films with defect densities equivalent to
MBE Ge films (~2 x 107 cm−2) could then probably be produced. 相似文献
15.
S. M. Hubbard D. Pavlidis V. Valiaev A. Eisenbach 《Journal of Electronic Materials》2002,31(5):395-401
Low-pressure, metal-organic vapor-phase epitaxy (MOVPE) was used to grow AlN/GaN metal-insulator-semiconductor (MIS) heterostructures
with AlN thickness between 3 nm and 30 nm. The Hall mobility was found to decrease with increasing AlN thickness, with optimal
mobility measured at 5-nm AlN. By decreasing the ammonia flow during AlN growth (lower V/III ratio), surface and interface
quality were greatly improved with a corresponding improvement in electrical properties. For the optimal V/III ratio, room-temperature
(RT) mobility and sheet charge were 891 cm2/Vs and 2.15×1013 cm−2, respectively. The best RT mobility, for both optimal V/III and thickness, was 1015 cm2/Vs with a sheet charge of 1.1×1013 cm−2. 相似文献
16.
J. H. Edgar Z. J. Yu David J. Smith J. Chaudhuri X. Cheng 《Journal of Electronic Materials》1997,26(12):1389-1393
The structure and crystal quality of epitaxial films of SiC/AlN/6H-SiC(0001) prepared by chemical vapor deposition were evaluated
by high resolution transmission electron microscopy (HRTEM) and x-ray diffraction techniques. Cross-sectional HRTEM revealed
an abrupt AlN layer-6H-SiC substrate junction, but the transition between the AlN and SiC layers was much rougher, leading
to the formation of a highly disordered SiC region adjacent to the interface. The AlN layer was relatively defect free, while
the SiC layer contained many microtwins and stacking faults originating at the top SiC/AlN interface. The SiC layer was the
3C-polytype, as determined by double crystal x-ray rocking curves. The SiC layers were under in-plane compressive stress,
with calculated defect density between 2–4×107 defects/cm−2. 相似文献
17.
S. Yu. Davydov 《Semiconductors》2011,45(8):1070-1076
An analytical expression for the density of states of a graphene monolayer interacting with a silicon carbide surface (epitaxial
graphene) is derived. The density of states of silicon carbide is described within the Haldane-Anderson model. It is shown
that the graphene-substrate interaction results in a narrow gap of ∼0.01–0.06 eV in the density of states of graphene. The
graphene atom charge is estimated; it is shown that the charge transfer from the substrate is ∼10−3–10−2
e per graphene atom. 相似文献
18.
Jau-Jiun Chen Soohwan Jang F. Ren Yuanjie Li Hyun-Sik Kim D. P. Norton S. J. Pearton A. Osinsky S. N. G. Chu J. F. Weaver 《Journal of Electronic Materials》2006,35(4):516-519
Wet etch rates at 25°C for Zn0.9Mg0.1O grown on sapphire substrates by pulsed laser deposition (PLD) were in the range 300–1100 nm · min−1 with HCl/H2O (5×10−3−2×10−2 M) and 120–300 nm · min−1 with H3PO4/H2O (5×10−3−2×10−2 M). Both of these dilute mixtures exhibited diffusion-limited etching, with thermal activation energies of 2–3 kCal · mol−1. By sharp contrast, the etch rates for ZnO also grown on sapphire by PLD were much slower in similar solutions, with rates
of 1.2–50 nm · min−1 in HCl/H2O (0.01–1.2 M) and 12–54 nm · min−1 in H3PO4/H2O (0.02–0.15 M). The etching was reaction limited over the temperature range 25–75°C, with activation energies close to 6
kCal · mol−1. The resulting selectivity of Zn0.9Mg0.1O over ZnO can be a high as ∼400 with HCl and ∼30 with H3PO4. 相似文献
19.
We have developed a technology for producing n-type GaxIn1−x
N/p-Si heterostructures by combined pyrolysis of indium and gallium monoammoniate chlorides, making it possible to obtain heterolayers
with composition varying over wide limits (from GaN up to InN). The composition and basic electric and optical characteristics
of nitride films were determined. The electric and photoelectric properties of the heterostructures with GaxIn1−x
N films of different composition were investigated. It was shown that the anisotypic heterojunction n-GaxIn1−x
N/p-Si is a promising photosensitive element for detecting visible-range radiation. The maximum values of the specific detectivity
were D*=1.2×1011 Hz1/2·W−1 at 290 K. A band diagram of the heterojunction was constructed.
Fiz. Tekh. Poluprovodn. 32, 461–465 (April 1998) 相似文献
20.
Enam Ahmed Chowdhury M. Dashiell G. Qiu J. O. Olowolafe R. Jonczyk D. Smith A. Barnett J. Kolodzey K. M. Unruh C. P. Swann John Suehle Yuan Chen 《Journal of Electronic Materials》1998,27(7):918-922
We report on the properties of a novel insulator, AlO:N for application in semiconductors produced by thermally oxidizing
AlN thin films. The process steps were similar to those used for SiO2, creating the possibility of a new technology for metal-insulator-semiconductor field effect devices and integrated circuits.
Thin films of AlN were deposited by radio-frequency magnetron reactive sputtering on p-type silicon or fused quartz substrates.
As-deposited AlN film thickness ranged from 0.05 to 0.7 μm, with polycrystalline structure revealed by x-ray diffraction.
Oxidation was performed under O2 flow at 800 to 1100°C for 1–4 h. AlN films were oxidized partially or fully into Al2O3, depending on initial thickness, oxidation temperature and time. X-ray diffraction indicates the presence of several phases
of Al2O3 at 1000°C, whereas at 1100°C, only the α-Al2O3 phase was found. Considering the importance of surface field effect device applications, the surfaces of oxidized films were
examined with atomic force microscopy in air, and a clear change was observed in the surface structure of the oxidized film
from that of as-deposited AlN films. Capacitance-voltage measurements of metal-oxide-semiconductor structures yielded a dielectric
constant of AlO:N between 8–12 and a net oxide-trapped-charge density of ∼1011 cm−2. Using Fourier transform infrared spectrometry transmittance and reflectance, some α-Al2O3 modes were observed. In this paper, we describe the general properties of the oxide thin films, bulk and interface, at different
temperatures. 相似文献