共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
We report deposition of (GaAs)1_x(Ge2)x on GaAs substrates over the entire alloy range. Growth was performed by metalorganic chemical vapor deposition at temperatures
of 675 to 750°C, at 50 and 760 Torr, using trimethylgallium, arsine, and germane at rates of 2–10 μ/h. Extrinsic doping was
achieved using silane and dimethylzinc in hydrogen. Characterization methods include double-crystal x-ray rocking curve analysis,
Auger electron spectroscopy, 5K photoluminescence, optical transmission spectra, Hall-effect, and Polaron profiling. Results
achieved include an x-ray rocking curve full-width at half maximum as narrow as 12 arc-s, Auger compositions spanning the
alloy range from x = 0.03 to x = 0.94, specular surface morphologies, and 5K photoluminescence to wavelengths as long as 1620
nm. Undoped films are n type, with n ≈ 1 × 1017 cm−3. Extrinsic doping with silane and dimethylzinc have resulted in films which are n type (1017 to 1018 cnr−3) or p type (5 × 1018 to 1 × 1020 cm−3). Mobilities are generally ≈ 50 cm2/V-s and 500 cm2/V-s, for p and n films, respectively. 相似文献
3.
Nanocrystalline diamond (NCD) films were produced by microwave plasma-enhanced chemical vapor deposition (MPECVD) using gas
mixtures of Ar, H2, and CH4. The structural properties, electron emission, and electric discharge behaviors of the NCD films varied with H2 flow rates during MPECVD. The turn-on field for electron emission at a pressure of 2.66 × 10−4 Pa increased from 4.2 V μm−1 for the NCD films that were deposited using a H2 flow rate of 10 cm3 min−1 to 7 V μm−1 for films deposited at a H2 flow rate of 20 cm3 min−1. The NCD film with a low turn-on field also induced low breakdown voltages in N2. The grain size and roughness of the NCD films may influence both the electron emission and the electric discharge behaviors
of the NCD cathodes. 相似文献
4.
Shih-Yuan Lin Ying-Chung Chen Chih-Ming Wang Kuo-Sheng Kao Chih-Yuan Chan 《Journal of Electronic Materials》2009,38(3):453-459
Calcium copper titanium oxide (CaCu3Ti4O12, abbreviated to CCTO) films were deposited on Pt/Ti/SiO2/Si substrates at room temperature (RT) by radiofrequency magnetron sputtering. As-deposited CCTO films were treated by rapid
thermal annealing (RTA) at various temperatures and in various atmospheres. X-ray diffraction patterns and scanning electron
microscope (SEM) images demonstrated that the crystalline structures and surface morphologies of CCTO thin films were sensitive
to the annealing temperature and ambient atmosphere. Polycrystalline CCTO films could be obtained when the annealing temperature
was 700°C in air, and the grain size increased signifi- cantly with annealing in O2. The 0.8-μm CCTO thin film that was deposited at RT for 2 h and then annealed at 700°C in O2 exhibited a high dielectric constant (ε′) of 410, a dielectric loss (tan δ) of 0.17 (at 10 kHz), and a leakage current density (J) of 1.28 × 10−5 A/cm2 (at 25 kV/cm). 相似文献
5.
Byoung Taek Lee Wan Don Kim Ki Hoon Lee Han Jin Lim Chang Seok Kang Horii Hideki Suk Ho Joo Hong Bae Park Cha Young Yoo Sang In Lee Moon Yong Lee 《Journal of Electronic Materials》1999,28(4):L9-L12
The influence of two-step deposition on the electrical properties of sputtered (Ba,Sr)TiO3 thin films was investigated. BST thin films with thickness 40 nm were deposited by a simple two-step radio frequency-magnetron
sputtering technique, where the BST thin film consisted of a seed layer and a main layer. The dielectric constant was strongly
dependent on the thickness of seed layer, but there was no dependence on deposition temperature of the seed layer. For a 2
nm seed layer, the dielectric constants were higher by about 29% than those of single-step BST thin films due to higher crystallinity
and the leakage current was nearly the same as that of a single-step sample in bias voltage from −2 to 2.5 V. However, an
improvement of the dielectric constant was not observed for samples having above 4 nm thick seed layers. A 40 nm thick BST
film with 2 nm thick seed layer deposited by a two-step method exhibited a SiO2 equivalent thickness of 0.385 nm and a leakage current density of 2.74 × 10−8A/cm2at+1.5V after post-annealing under an atmosphere of flowing N2 for 30 min at 750°C. 相似文献
6.
Plasma-deposited silicon nitride films were produced from SiH4-N2 gas mixture. Their composition, chemical bonds, and electrical properties were investigated by varying the deposition conditions.
The silicon nitride films from SiH4-N2 gas mixture exhibit (i) less hydrogen, (ii) higher thermal endurance, (iii) higher density, and (iv) smaller etching rate
than those of the films deposited from SiH4, and NH3 gas mixture. These results can be partly attributed to lower hydrogen concentration. As the Si/N ratio approaches the stoichiometric
value, 0.75, the resistivity and the breakdown strength are increased. They are 1015Ωcm and 9MV/cm, respectively, at Si/N≃0.85. Interface state density between silicon and silicon nitride layers is as low as
1& #x223C; 5xl011cm−2 eV−1.
On leave from The Northwest Telecommunication Engineering Institute, Xi’an, The People’s Republic of China. 相似文献
7.
La-modified lead titanate (PLT) thin films were prepared by hot-wall type low pressure-metalorganic chemical vapor deposition
method. Pb(dpm)2, La(dpm)3, and titanium tetraisopropoxide were used as source materials. The films were deposited at 500°C under the low pressure of
1000 mTorr and then annealed at 650°C for 10 min in oxygen ambient. Sputter-deposited platinum electrodes and 180 nm thick
PLT thin films were employed to form MIM capacitors with the best combination of high charge storage density (26.7 μC/cm2 at 3V) and low leakage current density (1.5 × 10-7 A/cm2 at 3V). The measured dielectric constant and dielectric loss were 1000∼1200 and 0.06∼0.07 at zero bias and 100 kHz, respectively. 相似文献
8.
Dual spectral source assisted metalorganic chemical vapor deposition (MOCVD) is an ideal technique for the deposition of high
dielectric constant materials. Tungsten halogen lamps and a deuterium lamp are used as the sources of optical and thermal
energy. In this paper, we have reported the deposition and characterization of tantalum penta oxide films. Ta2O5 films were deposited at 660°C for 15 min and annealed at 400°C for 1 h. The leakage current densities of 10.6 nm thick films
are as low as 10−10 A/cm2 for gate voltage under 4V. To the best of our knowledge, these are the best results reported to date by any researcher. The
high energy photons used in the in-situ cleaning and deposition process play an important role in obtaining high quality films of Ta2O5. 相似文献
9.
Thin films of InP were deposited on single crystals and thin films of CdS by the planar reactive deposition technique. Good
local epitaxy was observed on single crystals of CdS as well as InP and GaAs. The electrical evaluation of unintentionally
doped films on semi-insulating InP substrates show them to be n-type with room temperature electron concentrations ranging
from 5 × 1016 cm−3 to 5 × 1017 cm−3 and mobilities up to 1350 cm2/Vsec. For films intentionally doped with Mn and Be, p-type films were obtained. For Mn doping (deep acceptor level), room
temperature mobilities as high as 140 cm2/Vsec and free carrier concentrations as low as 5 × 1016 cm−3 (with dopant level of 3 × 1018 cm−3) were obtained. For Bedoped films, free carrier concentrations of about 5 × 1018 cm−3 and mobilities of 20 cm2/Vsec were found. Scanning electron microscope and microprobe pictures show appreciable interdiffusion between the InP/CdS
thin-film pair for InP deposited at 450°C. The loss of Cd from the CdS and the presence of an indium-cadmium-sulfur phase
at the InP/CdS interface were observed. Interdiffusion is alleviated for InP deposition at lower temperatures.
Supported in part by ERDA and AFOSR. 相似文献
10.
Ba6−3xNd8+2xTi18O54 with x=0.25 (BNT-0.25, or simply, BNT) dielectric thin films with a thickness of 320 nm have been prepared on Pt-coated silicon
substrates by pulsed laser deposition (PLD) at the substrate temperature of 650°C in 20 Pa oxygen ambient. X-ray analysis
showed that the as-deposited films are amorphous and the films remain amorphous after a postannealing at 750°C for 30 min.
The dielectric constant of the BNT films has been determined to be about 80 with a low loss tan δ of about 0.006 at 1 MHz.
The capacitance-voltage (C-V), capacitance-frequency, and capacitance-temperature characteristics of a BNT capacitor with
Pt top electrode were measured. A low leakage-current density of 4×10−6 A/cm2 at 6 V was measured, and a preliminary discussion of the leakage-current mechanism is also given. It is proposed that amorphous
BNT-0.25 thin films will be a potential dielectric material for microwave applications. 相似文献
11.
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
12.
A. G. Vasil’ev R. A. Zakharov A. A. Orlikovskii A. E. Rogozhin M. S. Sonin I. A. Khorin 《Russian Microelectronics》2009,38(5):327-333
Electrophysical studies of Me/HfO2/Si(100) structures formed by the electron-beam evaporation method are carried out. The layers of a subgate dielectric are
characterized by low values of the state density at the interfaces with silicon (∼1011 cm−2) as compared with values given for films formed by vapor deposition. It is shown that the structures are characterized by
small leakage currents and high breakdown voltages. 相似文献
13.
R. Qian B. Anthony T. Hsu J. Irby D. Kinosky S. Banerjee A. Tasch 《Journal of Electronic Materials》1992,21(4):395-399
In this work, remote plasma-enhanced chemical vapor deposition (RPCVD) has been used to grow Ge
x
Si1−x
/Si layers on Si(100) substrates at 450° C. The RPCVD technique, unlike conventional plasma CVD, uses an Ar (or He) plasma
remote from the substrate to indirectly excite the reactant gases (SiH4 and GeH4) and drive the chemical deposition reactions. In situ reflection high energy electron diffraction, selected area diffraction,
and plan-view and cross-sectional transmission electron microscopy (XTEM) were used to confirm the single crystallinity of
these heterostructures, and secondary ion mass spectroscopy was used to verify abrupt transitions in the Ge profile. XTEM
shows very uniform layer thicknesses in the quantum well structures, suggesting a Frank/ van der Merwe 2-D growth mechanism.
The layers were found to be devoid of extended crystal defects such as misfit dislocations, dislocation loops, and stacking
faults, within the TEM detection limits (∼105 dislocations/cm2). Ge
x
Si1−x
/Si epitaxial films with various Ge mole fractions were grown, where the Ge contentx is linearly dependent on the GeH4 partial pressure in the gas phase for at leastx = 0 − 0.3. The incorporation rate of Ge from the gas phase was observed to be slightly higher than that of Si (1.3:1). 相似文献
14.
T.J. de Lyon R.D. Rajavel A.T. Hunter J.E. Jensen M.D. Jack S.L. Bailey R.E. Kvaas V.K. Randall S.M. Johnson 《Journal of Electronic Materials》2008,37(9):1420-1425
An initial investigation of the use of atomic nitrogen for controlled p-type doping of wide-bandgap Hg0.3Cd0.7Te (x = 0.7) is reported. Mixtures of argon and nitrogen, ranging in nitrogen concentration from 0.1% to 100%, have been utilized
to demonstrate well-controlled nitrogen incorporation in the 1016 cm−3 to 1020 cm−3 range using total gas flow rates of 0.3 sccm to 4.0 sccm and radiofrequency (RF) powers of 100 W to 400 W. Nitrogen doping
exhibits several desirable attributes including abrupt turn-on and turn-off and minimal sensitivity to variations in growth
temperature and HgCdTe composition, with no negative effects on HgCdTe dislocation density and morphology. Preliminary electrical
measurements indicate primarily n-type behavior in the 1014 cm−3 to 1015 cm−3 range in as-grown x = 0.7 HgCdTe and CdTe films doped with nitrogen at 1018 cm−3 to 1020 cm−3 concentrations, while ZnTe films have exhibited p-type electrical activity with hole concentrations approaching 1020 cm−3. 相似文献
15.
A study of the thermally activated decomposition of Al(hfa)3 (aluminum hexafluoroacetylacetonate) from the gas phase to form Al2O3 on silicon substrates is reported. The decomposition process was carried out in an open tube atmospheric pressure reactor
in either argon or oxygen/argon mixtures in the temperature range, 350–450° C. The chemical vapor deposition process resulted
in the formation of aluminum oxide films in all instances. The dielectric strength of Al/Al2O3/Si capacitors which received a post-metal anneal, but did not receive a high temperature annealing treatment, with aluminum
oxide films prepared from Al(hfa)3 in argon, was found to be in the range 2–6 MV/cm. The difference between the flatband voltage of the MOS structures and the
metal-silicon work function difference was positive, indicative of a net negative oxide charge with a density of approximately
3 × 1011 – 3 × 1012 cm-2, assuming the charge is located at the oxide-silicon interface. Decomposition of Al(hfa)3 was also carried out in oxygen/argon mixtures with the oxygen concentration in the range 10–60 vol %. This process led to
the deposition of aluminum oxide films with breakdown fields in the range 8–9 MV/cm. However, the flatband voltages of the
Al/Al2O3/Si capacitors were even more positive than those obtained with Al2O3 formed in pure argon. High temperature (800–1000° C) oxygen or nitrogen annealing treatments of alumina films deposited in
either argon or oxygen/argon mixtures were evaluated from the point of view of their influence on the oxide film properties.
In particular, an annealing process in oxygen at 1000° C for 15 min was found to result in a reduction of the net negative
oxide charge, and an improvement of the dielectric strength of films deposited in argon. Films formed in oxygen/argon mixtures
did not change appreciably following oxygen annealing, as far as breakdown fields are concerned, but the oxide net negative
charge was reduced. As in an earlier study by the authors, of copper film deposition from Cu(hfa)2, it was found that essentially carbon free films could be obtained under appropriate conditions. 相似文献
16.
S. S. Hullavarad D. E. Pugel E. B. Jones R. D. Vispute T. Venkatesan 《Journal of Electronic Materials》2007,36(6):648-653
Hafnium oxide (HfO2) thin films were deposited by the pulsed laser deposition (PLD) method on SiC substrates. The bandgap of HfO2 thin films was observed to be 5.8 eV. The chemical nature and stoichiometry of the films were analyzed by x-ray photoelectron
spectroscopy (XPS). Metal-insulator-semiconductor (MIS) structures with Ni as a top electrode and TiN as a bottom electrode
were fabricated to study the leakage current properties. The devices exhibited leakage current density of 50 nA/cm2. The dielectric constant of these films is estimated to be in the range 17–24 from capacitance-voltage (C-V) measurements.
The frequency dependence of the interface trapped charges is studied. 相似文献
17.
M. Pan J. Nause V. Rengarajan R. Rondon E.H. Park I.T. Ferguson 《Journal of Electronic Materials》2007,36(4):457-461
N-doped p-type ZnO thin films were grown on c-sapphire substrates, semi-insulating GaN templates, and n-type ZnO substrates by metal organic chemical vapor deposition (MOCVD). Diethylzinc and oxygen were used as precursors for
Zn and O, respectively, while ammonia (NH3) and nitrous oxide (N2O) were employed as the nitrogen dopant sources. X-ray diffraction (XRD) studies depicted highly oriented N-doped ZnO thin
films. Photoluminescence (PL) measurements showed a main emission line around 380 nm, corresponding to an energy gap of 3.26 eV.
Nitrogen concentration in the grown films was analyzed by secondary ion mass spectrometry (SIMS) and was found to be on the
order of 1018 cm−3. Electrical properties of N-doped ZnO epilayers grown on semi-insulating GaN:Mg templates were measured by the Hall effect
and the results indicated p-type with carrier concentration on the order of 1017 cm−3. 相似文献
18.
Hf-O-N and HfO2 thin films were evaluated as barrier layers for Hf-Ti-O metal oxide semiconductor capacitor structures. The films were processed by sequential pulsed laser deposition at 300 °C and ultra-violet ozone oxidation process at 500 °C. The as-deposited Hf-Ti-O films were polycrystalline in nature after oxidation at 500 °C and a fully crystallized (o)-HfTiO4 phase was formed upon high temperature annealing at 900 °C. The Hf-Ti-O films deposited on Hf-O-N barrier layer exhibited a higher dielectric constant than the films deposited on the HfO2 barrier layer. Leakage current densities lower than 5 × 10 A/cm2 were achieved with both barrier layers at a sub 20 Å equivalent oxide thickness. 相似文献
19.
In1−xMnxAs diluted magnetic semiconductor (DMS) thin films with x 0.14 have been grown using organometallic vapor phase epitaxy. Tricarbonyl-(methylcyclopentadienyl)manganese
was successfully used as the Mn source. Single phase, epitaxial films were achieved for compositions as high as x=0.14 using
growth temperatures ≥475°C. For lower growth temperatures or x>0.14, nanometer scale MnAs precipitates were observed within
the In1−xMnxAs matrix. Transport properties were investigated using the Hall effect. All Mn doped films were p-type with single phase
films exhibiting hole concentrations 2≤×1019 cm−3. Magnetization was measured as a function of temperature and applied field for a single phase film with x=0.1. Ferromagnetic
ordering was observed at 5 K with a saturation magnetization of Ms=68 emu/cm3, a remnant magnetization, Mr=10 emu/cm3, and a coercive field Hc=400 Oe. 相似文献
20.
Thin films of the semiconducting compound Mg2Ge were deposited by magnetron cosputtering from source targets of high-purity Mg and Ge onto glass substrates at temperatures
T
s = 300°C to 700°C. X-ray diffraction shows that the Mg2Ge compound begins to form at a substrate temperature T
s ≈ 300°C. Films deposited at T
s = 400°C to 600°C are single-phase Mg2Ge and have strong x-ray peaks. At higher T
s the films tend to be dominated by a Ge-rich phase primarily due to the loss of magnesium vapor from the condensing film.␣At
optimum deposition temperatures, 550°C to 600°C, films have an electrical conductivity σ
600 K = 20 Ω−1 cm−1 to 40 Ω−1 cm−1 and a Seebeck coefficient α = 300 μV K−1 to 450 μV K−1 over a broad temperature range of 200 K to 600 K. 相似文献