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1.
D. Gregušová T. Lalinský ž. Mozolová J. Breza P. Vogrinčič 《Journal of Materials Science: Materials in Electronics》1993,4(3):197-199
The investigation of thermal stability of WN
x
/GaAs Schottky contacts prepared by selective ion implantation of nitrogen into tungsten film has been demonstrated. Auger electron spectroscopy was used for characterization of thermal stability of the interfaces after rapid thermal annealing at 950 C for 10s. Significant oxygen influence on migration of Ga atoms from the substrate into metallization systems was observed. 相似文献
2.
A. Lipsanen P. Kuivalainen E. Rauhala A. Seppa¨la¨ S. Franssila 《Journal of Materials Science: Materials in Electronics》2003,14(5-7):315-318
The thermal stability of Cu/WN
x
/Si multilayer structures fabricated by using reactive d.c. magnetron sputtering was studied using rapid thermal annealing (RTA) and several analytic methods. The analytic methods included four-point resistance measurements, X-ray diffraction analysis, Rutherford backscattering spectrometry, and optical and scanning electron microscopy. The barrier performance of WN
x
-layers is compared to the performance of sputtered W layers. It is shown that a 15-nm thick tungsten nitride (WN
x
) layer prevents the destructive reactions up to 700 °C for a 12-s RTA process in a nitrogen atmosphere. 相似文献
3.
H. F. Chuang C. P. Lee S. C. Wu 《Journal of Materials Science: Materials in Electronics》1991,2(1):28-33
The thermal stability of MoSi
x
Schottky contacts to GaAs has been studied. The contacts were analysed by Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), sheet resistance, and current-voltage measurements. We have studied MoSi
x
with the compositionsx=0, 0.3, 0.6, 1, and 2. The films were annealed at various temperatures up to 850°C. The thermal stability of the films is found to bex-dependent. The best composition for thermally stable Schottky contacts is Mo5Si3. Good Schottky characteristics were retained with annealing temperatures up to 850°C for 30 min. 相似文献
4.
《Science and Technology of Advanced Materials》2002,3(1):1-27
Recent strong demands for optoelectronic communication and portable telephones have encouraged engineers to develop optoelectronic devices, microwave devices, and high-speed devices using hetero-structural GaAs-based compound semiconductors. Although the GaAs crystal growth techniques had reached a level to control the compositional stoichiometry and crystal defects on a nearly atomic scale by the advanced techniques such as molecular beam epitaxy and metal organic chemical vapor deposition techniques, development of ohmic contact materials (which play a key role to inject external electric current from the metals to the semiconductors) was still on a trial-and-error basis.Our research efforts have been focused to develop low resistance, refractory ohmic contact materials to n-type GaAs using the deposition and annealing techniques, and it was found the growth of homo-or hetero-epitaxial intermediate semiconductor layers (ISL) on the GaAs surface was essential for the low resistance ohmic contact formation. In this paper, two typical examples of ohmic contact materials developed by forming ISL were given. The one was refractory NiGe-based ohmic contact material, which was developed by forming the homo-epitaxial ISL doped heavily with donors. This heavily doped ISL was discovered to be formed through the regrowth mechanism of GaAs layers at the NiGe/GaAs interfaces during annealing at elevated temperatures. To reduce the contact resistance further down to a value required by the device designers, an addition of small amounts of third elements to NiGe, which have strong binding energy with Ga, was found to be essential. These third elements contributed to increase the carrier concentration in ISL. The low resistance ohmic contact materials developed by forming homo-epitaxial ISL were Ni/M/Ge where a slash ‘/’ denotes the deposition sequence and M is an extremely thin (∼5 nm) layer of Au, Ag, Pd, Pt or In. The other was refractory InxGa1−xAs-based ohmic contact materials which were developed by forming the hetero-epitaxial ISL with low Schottky barrier to the contacting metals by growing the InxGa1−xAs layers on the GaAs substrate by sputter-depositing InxGa1−xAs targets and subsequently annealing at elevated temperatures. To reduce the contact resistance, it was found that this InxGa1−xAs (ISL) layer had to have In compositional gradient normal to the GaAs surface: the In concentration being rich at the metal/InxGa1−xAs interface and poor close to the InxGa1−xAs/GaAs interface. This concentration graded ISL reduced both the barrier heights at the metal/ISL and ISL/GaAs interfaces and reduced the contact resistance. The ohmic contact materials developed by forming hetero-epitaxial ISL was In0.7Ga0.3As/Ni/WN2/W. These contact materials formed refractory compounds at the interfaces, which was also found to be essential to improve thermal stability of ohmic contacts used in the GaAs devices. 相似文献
5.
I. Ya. Mittova E. V. Tomina A. A. Lapenko A. O. Khorokhordina 《Inorganic Materials》2004,40(5):441-444
It is shown that vanadium layers deposited by magnetron sputtering onto GaAs accelerate surface oxide growth during thermal oxidation. The processes occurring during thermal oxidation on the surface and at the semiconductor–metal interface are interpreted under the assumption that vanadium deposition leads to the formation of an interfacial V
x
Ga
y
As
z
layer, which plays a key role in determining the mechanism of V/GaAs oxidation. 相似文献
6.
We report the resistive switching (RS) characteristics of tungsten nitride (WNx) thin films with excellent complementary metal-oxide-semiconductor (CMOS) compatibility. A Ti/WNx/Pt memory cell clearly shows bipolar RS behaviors at a low voltage of approximately ±2.2 V. The dominant conduction mechanisms at low and high resistance states were verified by Ohmic behavior and trap-controlled space-charge-limited conduction, respectively. A conducting filament model by a redox reaction explains the RS behavior in WNx films. We also demonstrate the memory characteristics during pulse operation, including a high endurance over >105 cycles and a long retention time of >105 s. 相似文献
7.
Epitaxial layers of (Si2)1−x
(GaAs)x (0≤x≤0.85) solid solutions were grown by liquid phase epitaxy in a temperature interval from 850 to 700°C from a tin-based solution
melt confined between two horizontal polycrystalline silicon substrates. The dependence of the quality and parameters of the
epilayers on the process conditions have been studied. The obtained Si-(Si2)1−x
(GaAs)x structures can be used in various microelectronic and photoconversion devices, replacing analogous but more expensive GaAs-based
structures. Experimental data on the electrical properties and photoelectric characteristics of the Si-(Si2)1−x
(GaAs)x structures are presented. 相似文献
8.
R Pal M Singh R Murlidharan S K Agarwal D Pal D N Bose 《Bulletin of Materials Science》1998,21(4):313-316
In
x
Ga1−x
As (0·06≤x≤0·35) epilayers were grown on GaAs substrates by atmospheric pressure metal organic chemical vapour deposition technique.
Surface morphology and lattice mismatch in the InGaAs/GaAs films of different compositions were studied. Cross-hatched patterns
were observed on the surface of the epilayers for bulk alloy composition up tox≈0·25. Forx>0·3, a rough textured surface morphology was observed. 相似文献
9.
Kuo-Yi Lim Daniel J. Ripin Gale S. Petrich Pierre R. Villeneuve Shanhui Fan J. D. Joannopoulos Erich P. Ippen Leslie A. Kolodziejski 《Advanced materials (Deerfield Beach, Fla.)》1999,11(6):501-505
Recent work on optical microcavities is concisely reviewed in this article. Optical microcavities can be fabricated using III–V compound semiconductors by introducing a large periodic refractive-index variation along the axis of GaAs waveguides. Strong optical confinement in the microcavities is achieved by oxidizing the underlying III–V material and further optimized by preferentially etching away the oxide to form an air-bridge structure. The III–V thermal oxide is obtained from the wet thermal oxidation of high Al-content AlxGa1–xAs material. The critical role of the thermal oxide in the design and fabrication of the waveguide microcavities is outlined and the characterization of the properties of the thermal oxide salient to the fabrication of the devices is described. Finally, preliminary transmission data demonstrating the successful realization of these microcavities are presented. 相似文献
10.
Ni-Al hydrotalcite compounds with the structural formula [Ni1–x
Al
x
(OH)2]
x+ [(CO3)
x/2 ·mH2O]
x– were synthesized in the composition range Al/Ni+Al (x)=0.20–0.50 by sequential precipitation. The samples were characterized by X-ray diffraction, infrared absorption, thermogravimetry-differential scanning calorimetry-evolved gas analysis, transmission electron microscopy and BET surface-area measurements. The crystallinity and the lattice parameters of the samples are significantly affected with respect to composition. Hydrothermal treatments performed on the aged samples enhanced the crystallinity. The nitrate ion is also present along with carbonate ion as the charge-balancing anion in the interlayer space. The thermal stability of these materials increased with decrease in Ni/Al atomic ratio. Thermal calcination of these compounds yielded non-stoichiometric NiO whose crystallinity and thermal stability depends on the composition as well as on calcination temperature. 相似文献
11.
N. S. Boltovets A. V. Zorenko V. N. Ivanov S. I. Vlaskina R. V. Konakova Ya. Ya. Kudrik P. M. Litvin O. S. Litvin V. V. Milenin S. K. Abdizhaliev 《Technical Physics Letters》2003,29(1):22-25
The effect of rapid thermal treatment at T=1000°C on the formation of \textTiBx - n-\textSiC6H(00\text1-- ){\text{TiB}}_x - n--{\text{SiC6H(00}}\mathop {\text{1}}\limits^-- ) barrier contacts and Ni-n-SiC6H(0001) ohmic contacts was studied. In the former case, thermal treatment neither disturbs the layer structure nor reduces the thermal stability of the barrier contacts. The rapid annealing of an Ni-n-SiC6H(0001) structure results in the formation of a stable ohmic contact. At the same time, this treatment does not change the parameters of the static current-voltage characteristics of the \textAu - \textTiBx - n-\textSiC6H(00\text1-- ){\text{Au}} - {\text{TiB}}_x - n--{\text{SiC6H(00}}\mathop {\text{1}}\limits^-- ) Schottky diodes. These thermally stable diodes are characterized by a sensitivity of ∼3300–3500 mV/mW at an incident radiation power of 10–7 W and are capable of operating at a microwave power of up to 1 W. The dynamic range of a linear portion of the conversion characteristic reaches up to 50 dB. 相似文献
12.
Kao-Feng Yarn C. I. Liao C. L. Lin 《Journal of Materials Science: Materials in Electronics》2006,17(4):251-265
A review of the technique of direct growing high-quality InxGa1−xAs or InP buffer layers on GaAs substrates by metal-organic chemical vapor deposition (MOCVD) is given. This low-temperature
growth method benefits the improvement of metamorphic device performance. In this work, a simple and novel method of directly
deposited thin InxGa1−xAs or InP buffer layers (< 1 μm) on GaAs substrates is presented, instead of strained-layer superlattice, two-step, graded
or CS (compliant substrates) methods, while maintaining low dislocations, high crystal quality, and uniform and mirror like
surfaces. For the direct growth technique of InxGa1−xAs on GaAs, we found an excellent quality In0.54Ga0.46As buffer of rms surface roughness of only 0.686 nm by AFM and FWHM of 925 arcsec by XRD can be obtained at a low growth temperature
of 440∘C with a constant Ga/Ingas partial pressure of 5. The superior results are mainly due to the use of low temperature growth technology. In addition,
we also found this growth technology is available to directly grow InP buffer layers on GaAs. Experimental results conclude
that the growth temperature of 480∘C in harmony with the V/III ratios range of 130–210 is a suitable window to directly grow InP on GaAs substrates. 相似文献
13.
D. G IVEY R ZHANG Z ABID S EICHER T. P LESTER 《Journal of Materials Science: Materials in Electronics》1997,8(5):281-288
Microstructural evolution during the annealing of Pd/Pt/Au/Pd p-ohmic contacts (with and without a thin layer of Zn) to InGaP/GaAs
HBTs has been studied using transmission electron microscopy (TEM). Metal layers were deposited by electron beam evaporation
directly onto the InGaP emitter layer with the intention of consuming the InGaP during annealing to contact the heavily C-doped
p-type GaAs (3×1019 cm−3) base layer below. Initial reaction between Pd and Pt and InGaP formed a five-component amorphous layer (Pd, Pt, In, Ga and
P), which crystallized to (PtxPd1−x)5(InyGa1−y)P (0≤x, y≤1) at the interface between Pt and the amorphous layer. Annealing at temperatures ≥415°C caused complete decomposition
of the InGaP and partial decomposition of the GaAs base layer, producing a contact consisting of (PtxPd1−x)5(InyGa1−y)P, PtAs2 and PdGa. The attainment of low contact resistances did not depend on the presence of Zn. Minimum values of 0.10−0.12 Ω mm
were achieved after annealing at 415–440°C for contacts both with and without Zn.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Schottky contacts of refractory metal nitrides formed by reactive sputtering on n-type gallium nitride (GaN) were electrically evaluated, including film resistivity, Schottky characteristics and thermal stability. For the metal nitrides of TiNx, MoNx and ZrNx, resistivities of 108.3, 159.0 and 270.0 μΩcm were obtained, respectively. Current-voltage (I-V) characteristics showed that the ideality factor varied from 1.03 to 1.16, while the Schottky barrier height (SBH) varied from 0.66 to 0.79 eV for the three kinds of Schottky contacts. Especially for the ZrNx contact, the ideality factor and SBH were improved after annealing at 800 °C for 30 s. Schottky contact utilizing a refractory metal nitride on GaN shows its potential to develop thermally stable GaN devices. 相似文献
15.
G. A. Medvedkin 《Technical Physics Letters》2002,28(11):889-892
A process of the multivalent substitution of Mn atoms for cations in Ga1−x
MnxAs (a base material) is proposed. According to this approach, the two-cation ternary compound with a chalcopyrite structure
is used as a component forming a solid solution with GaAs. Based on the successful prediction and growth of high-temperature
chalcopyrite ferromagnets, it is expected that the content of Mn in Ga1−x
MnxAs can be increased. Quasi-binary (GaAs)1−x
(ZnGeAs2)x:Mn and (GaAs1−x
(CdSiAs2)x:Mn solid solutions are considered as candidate materials possessing higher Curie temperatures as compared to that of Ga1−x
MnxAs. 相似文献
16.
We have estimated the elastic properties of In1 − x
Ga
x
As/GaAs heterostructures and the characteristics of misfit dislocations in such heterostructures: misfit dislocation spacing,
Burgers vector length in various interfaces, surface density of dangling bonds, film/substrate interface energy, critical
film thickness below which pseudomorphic growth is possible without misfit dislocations, elastic strain energy of the film-substrate
system, average elastic strain of a thin-film island as a function of its radius, thermal stresses induced by the thermal-expansion
and lattice mismatches between the layers in contact, and crack length in the film. 相似文献
17.
Several spinel compositions, i.e. Mn1+x
Cr2−x
O4 (x = 0.7, 0.5, 0), MnFe
x
Cr2−x
O4 (x = 0.1, 1), MgMnCrO4 and Mg1+x
Cr2−x
O4 (x = 0, 0.1) were synthesised and studied in terms of phase analysis, density, stability in reducing atmosphere, electrical
conductivity and thermal expansion behaviour. The spinel samples were single phase, with cell parameter values in a good correlation
with cation sizes. Most of the studied spinels were found to be unstable under reducing conditions of thermal treatment, except
MnCr2O4, MgCr2O4 and Mg1.1Cr1.9O4. Electrical properties have been investigated by impedance spectroscopy and DC conductivity measurements at temperatures
between 200 and 900 °C. 相似文献
18.
Tungsten nitride carbide (WNxCy) thin films were deposited by chemical vapor deposition using the dimethylhydrazido (2−) tungsten complex (CH3CN)Cl4W(NNMe2) (1) in benzonitrile with H2 as a co-reactant in the temperature range 300 to 700 °C. Films were characterized using X-ray diffraction (XRD), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy and four-point probe to determine film crystallinity, composition, atomic bonding, and electrical resistivity, respectively. The lowest temperature at which growth was observed from 1 was 300 °C. For deposition between 300 and 650 °C, AES measurements indicated the presence of W, C, N, and O in the deposited film. The films deposited below 550 °C were amorphous, while those deposited at and above 550 °C were nano-crystalline (average grain size < 70 Å). The films exhibited their lowest resistivity of 840 µΩ-cm for deposition at 300 °C. WNxCy films were tested for diffusion barrier quality by sputter coating the film with Cu, annealing the Cu/WNxCy/Si stack in vacuum, and performing AES depth profile and XRD measurement to detect evidence of copper diffusion. Films deposited at 350 and 400 °C (50 and 60 nm thickness, respectively) were able to prevent bulk Cu transport after vacuum annealing at 500 °C for 30 min. 相似文献
19.
Negative photo-induced currents and negative differential characteristics of photoinduced current have been obtained successfully
under weak photoexcitations at 300 K for a new optoelectronic sensor including a carrier-storage layer of InAs/GaAs short
period superlattice. The phenomena are useful to imitate the selectivity functions in visual recognition, which is based on
the difference-of-Gaussian functionlike distribution of light sensitivity in the receptive fields in visual cortex. The phenomena
are strongly dependent on the material of the carrier-storage layer, where the photogenerated carriers are separated spatially
due to the Schottky forward voltage. The carrier separation is more enhanced as the ratio of electron mobility to hole mobility
becomes higher for the material of the carrier-storage layer. This means the In-rich InGaAs material is superior to the Ga-rich
one. In addition, compared with In
x
Ga1-x
As alloy, the improved surface morphology, the high electron mobility at room temperature and the narrow energy bandgap are
observed in the case of InAs/GaAs short period superlattice. That is the InAs/GaAs short period superlattice is superior to
In
x
Ga1-x
As alloy as the material for the carrier-storage layer. 相似文献
20.
C. Mejía-García A. Winter M. López-López A. Gilinsky H. Pascher 《Journal of Materials Science: Materials in Electronics》2007,18(11):1157-1161
Quantum well (QW) structures of Al
x
Ga1-x
As/GaAs with x = 0.3 were characterized by photoluminescence spectroscopy (PL) with circularly polarized excitation at a temperature of
1.6 K. The samples contained three QWs with thickness of 7, 5, and 3 nm grown by molecular beam epitaxy (MBE) on a 500 nm
thick buffer layer. Four samples with identical geometry but different surface treatments (in-situ etching the GaAs buffer
with Cl2 at different temperatures, and air-exposed buffer, respectively) were compared. The degree of circular polarization of the
PL and its decrease in a magnetic field applied perpendicularly to the direction of propagation of light (Hanle effect) allows
the determination of the interband lifetime τ and the spin lifetime τ
s
of the electrons. These lifetimes were different in the different QWs and strongly depend on the growth procedure. 相似文献