共查询到20条相似文献,搜索用时 15 毫秒
1.
L.F. Voss L. Stafford R. Khanna B.P. Gila C.R. Abernathy S.J. Pearton F. Ren I.I. Kravchenko 《Journal of Electronic Materials》2007,36(12):1662-1668
The use of TaN, TiN, and ZrN diffusion barriers for Ti/Al-based contacts on n-GaN (n ∼ 3 × 1017 cm−3) is reported. The annealing temperature (600–1,000°C) dependence of the Ohmic contact characteristics using a Ti/Al/X/Ti/Au
metallization scheme, where X is TaN, TiN, or ZrN, deposited by sputtering was investigated by contact resistance measurements
and Auger electron spectroscopy (AES). The as-deposited contacts were rectifying and transitioned to Ohmic behavior for annealing
at ≥600°C. A minimum specific contact resistivity of ∼6 × 10−5 Ω-cm−2 was obtained after annealing over a broad range of temperatures (600–900°C for 60 s), comparable to that achieved using a
conventional Ti/Al/Pt/Au scheme on the same samples. The contact morphology became considerably rougher at the high end of
the annealing range. The long-term reliability of the contacts at 350°C was examined; each contact structure showed an increase
in contact resistance by a factor of three to four over 24 days at 350°C in air. AES profiling showed that the aging had little
effect on the contact structure of the nitride stacks. 相似文献
2.
T.N. Oder P. Martin A.V. Adedeji T. Isaacs-Smith J.R. Williams 《Journal of Electronic Materials》2007,36(7):805-811
We report on improved electrical properties and thermal stability of ZrB2 Schottky contacts deposited on n-type 4H-SiC at temperatures between 20°C and 800°C. The Schottky barrier heights (SBHs) determined by current-voltage measurements
increased with deposition temperature, from 0.87 eV for contacts deposited at 20°C to 1.07 eV for those deposited at 600°C.
The Rutherford backscattering spectroscopy (RBS) spectra of these contacts revealed a decrease in oxygen peak with an increase
in the deposition temperature and showed no reaction at the ZrB2/SiC interface. These results indicate improved electrical and thermal properties of ZrB2/SiC Schottky contacts, making them attractive for high-temperature applications. 相似文献
3.
Dongwon Yoo Jae Boum Limb Jae-Hyun Ryou Wonseok Lee Russell D. Dupuis 《Journal of Electronic Materials》2007,36(4):353-358
The optimization of growth parameters, epitaxial structure, and device design for full-vertical gallium nitride (GaN) p-i-n rectifiers grown on n-type 6H-SiC substrates employing AlGaN:Si conducting buffer layers have been studied. The Al
x
Ga1−x
N:Si (x = ~0.1) nucleation layer is calibrated to be capable of acting as a good buffer layer for subsequent GaN growth as well as
to provide excellent electrical properties. Two types of full-vertical devices were fabricated and compared: one without any
current guiding and the other with the current guiding in the p-layer. The reverse breakdown voltage for rectifiers with a relatively thin 2.5-μm-thick i-region without p-current guiding was found to be over −330 V, while one with p-current guiding was measured to be over −400 V. Devices with p-current guiding structures exhibit reduced reverse leakage current by an order of magnitude >4 at −100 V. 相似文献
4.
F.D. Auret S. Coelho W.E. Meyer C. Nyamhere M. Hayes J.M. Nel 《Journal of Electronic Materials》2007,36(12):1604-1607
The authors have investigated by deep level transient spectroscopy the electron traps introduced in n-type Ge during sputter deposition of Au Schottky contacts. They have compared the properties of these defects with those
introduced in the same material during high-energy electron irradiation. They found that sputter deposition introduces several
electrically active defects near the surface of Ge. All these defects have also been observed after high-energy electron irradiation.
However, the main defect introduced by electron irradiation, the V-Sb center, was not observed after sputter deposition. Annealing
at 250°C in Ar removed the defects introduced during sputter deposition. 相似文献
5.
J.S. Wright L. Stafford B.P. Gila D.P. Norton S.J. Pearton Hung-Ta Wang F. Ren 《Journal of Electronic Materials》2007,36(4):488-493
The effect of cryogenic temperatures during metal deposition on the contact properties of Pd, Pt, Ti, and Ni on bulk single-crystal
n-type ZnO has been investigated. Deposition at both room and low temperature produced contacts with Ohmic characteristics
for Ti and Ni metallizations. By sharp contrast, both Pd and Pt contacts showed rectifying characteristics after deposition
with barrier heights between 0.37 eV and 0.69 eV. Changes in contact behavior were measured on Pd to anneal temperatures of
∼300 °C, showing an increase in barrier height along with a decrease in ideality factor with increasing annealing temperature.
This difference with annealing temperature is in sharp contrast to previous results for Au contacts to ZnO. There were no
differences in near-surface stoichiometry for the different deposition temperatures; however, low temperature contacts demonstrated
some peeling/cracking for Pt and Pd. 相似文献
6.
Biprodas Dutta Jugdersuren Battogtokh David Mckewon Igor Vidensky Neilanjan Dutta Ian L. Pegg 《Journal of Electronic Materials》2007,36(7):746-752
NaCo2O4 has one of the highest figures of merit among all ceramic thermoelectric materials. Because of its large thermopower and
low resistivity, the ceramic oxide NaCo2O4 is a promising candidate for potential thermoelectric applications. NaCo2O4 is, moreover, a ceramic compound with high decomposition temperature and chemical stability in air and it does not contain
any toxic elements. Like all 3-d transition ions, Co ions have multiple spin and oxidation states. In this investigation,
thermopower and electrical conductivity of NaCo2O4 as a function of substitution of Co by Fe ions were measured. Fe substitution for Co causes resistivity to increase, whereas
the Seebeck coefficient remained nearly invariant, especially above 330 K.
An erratum to this article can be found at 相似文献
7.
X. Wang G. Yu B. Lei X. Wang C. Lin Y. Sui S. Meng M. Qi A. Li 《Journal of Electronic Materials》2007,36(6):697-701
The n-GaN films grown by metal-organic chemical vapor deposition (MOCVD) are etched in an inductively coupled plasma (ICP) reactor
chamber. Atomic-force microscopy (AFM) characterization shows an increase of the surface roughness after the etching. Furthermore,
Hall measurement and photoluminescence (PL) spectra highlight deterioration of the electrical and optical properties, respectively.
Attempts to recover the damage are carried out by nitrogen plasma treatments accompanied by thermal annealing at the growth
temperature in a molecular-beam epitaxy (MBE) chamber. Improved electrical and optical properties compared with those of the
as-etched GaN, evidenced in both Hall and PL measurements, show a pronounced decrease of the damage introduced by the ICP
etching. 相似文献
8.
A reaction study of Cu
x
Ni
y
alloy (x = 0.2–0.95) under bump metallization (UBM) with Sn-Ag-zCu solder (z = 0–0.7) was conducted. Formation and separation of intermetallic compounds (IMCs), effect of Cu addition to the Cu
x
Ni
y
alloy and the solders, and compatibility of reaction products with currently available phase diagrams are extensively investigated.
The increase of Cu content both in the Cu
x
Ni
y
alloy and in the solder promoted IMC growth and Cu
x
Ni
y
consumption; though, with regard to solder composition, the reverse trend was true of the solder reactions in the literature.
The liquid + Cu6Sn5 area in the Sn-rich corner needs to be larger compared to the currently available Cu-Ni-Sn ternary phase diagram, and the
maximum simultaneous soluble point of Ni and Cu in Sn needs also to be moved to the Ni-Sn side (e.g., Sn-0.6Cu-0.3Ni). 相似文献
9.
W.T. Lim P.W. Sadik D.P. Norton B.P. Gila S.J. Pearton I.I. Kravchenko F. Ren 《Journal of Electronic Materials》2008,37(2):161-166
The use of Ir diffusion barriers in Ni/Au-based Ohmic contacts to p-type CuCrO2 layers was investigated. A specific contact resistance of ~5 × 10−4 Ω cm2 was achieved after annealing at 500°C for the Ir-containing contacts, and the contacts were rectifying for lower anneal temperatures.
In this case, the contact resistance was basically independent of the measurement temperature, indicating that tunneling is
the dominant transport mechanism in the contacts. The morphology for the Ir-containing contacts was still smooth at 500°C
although Auger electron spectroscopy depth profiling showed that some of the nickel had diffused to the surface and had oxidized.
Contacts annealed at 800°C showed that some copper and most of the nickel had diffused to the surface and oxidized. The presence
of the Ir diffusion barrier does increase the thermal stability of the contacts by ∼200°C compared to conventional Ni/Au contacts.
By contrast, the use of other materials such as TaN, ZrN, and W2B5 as the diffusion barrier led to poorer thermal stability, with the contact resistance increasing sharply above 400°C. 相似文献
10.
D. A. Usanov A. V. Skripal A. V. Abramov A. S. Bogolyubov V. S. Skvortsov M. K. Merdanov 《Semiconductors》2010,44(13):1685-1688
A one-dimensional waveguide photonic structure—specifically, a photonic crystal with a controllable frequency characteristic—is
designed. The central frequency of the spectral window of the photonic crystal can be tuned by choosing the parameters of
disturbance of periodicity in the photonic crystal, whereas the transmission coefficient at a particular frequency can be
controlled by varying the voltage at a p-i-n diode. It is shown that the possibility exists of using the waveguide photonic crystal to design a microwave device operating
in the 3-cm-wavelength region, with a transmission band of 70 MHz at a level 3 dB and the transmission coefficient controllable
in the range from −1.5 to −25 dB under variations in the forward voltage bias at the p-i-n diode from zero to 700 mV. 相似文献
11.
V. Ponnambalam Bo Zhang Terry M. Tritt S. Joseph Poon 《Journal of Electronic Materials》2007,36(7):732-735
The usefulness of half-Heusler (HH) alloys as thermoelectrics has been mainly limited by their relatively large thermal conductivity,
which is a key issue despite their high thermoelectric power factors. In this regard, Bi-containing half-Heusler alloys are
particularly appealing, because they are, potentially, of low thermal conductivity. One such a material is ZrCoBi. We prepared
pure and Ni-doped ZrCoBi by a solid-state reaction. To evaluate thermoelectric potential we measured electrical resistivity
(ρ = 1/σ) and thermopower (σ) up to 1000 K and thermal conductivity (κ) up to 300 K. Our measurements indicate that for these alloys resistivity of approximately a few mΩ cm and thermopower larger
than a hundred μV K−1 are possible. Low κ values are also possible. On the basis of these data we conclude that this system has a potential to be optimized further,
despite the low power factors (α
2
σT) we have currently measured. 相似文献
12.
T. N. Oder T. L. Sung M. Barlow J. R. Williams A. C. Ahyi T. Isaacs-Smith 《Journal of Electronic Materials》2009,38(6):772-777
High-temperature processing was used to improve the barrier properties of three sets of n-type 4H-SiC Schottky diodes fabricated with Ni Schottky contacts. We obtained an optimum average barrier height of 1.78 eV
and an ideality factor of 1.09 using current–voltage measurements on diodes annealed in vacuum at 500°C for 24 h. Nonannealed
contacts had an average barrier height of 1.48 eV and an ideality factor of 1.85. The Rutherford backscattering spectra of
the Ni/SiC contacts revealed the formation of a nickel silicide at the interface, accompanied by a substantial reduction in
oxygen following annealing. 相似文献
13.
B.A. Park C.A. Musca J. Antoszewski J.M. Dell L. Faraone 《Journal of Electronic Materials》2007,36(8):913-918
Exposure of p-type HgCdTe material to Ar/H2-based plasma is known to result in p-to-n conductivity-type conversion. While this phenomenon is generally undesirable when aiming to perform physical etching for
device delineation and electrical isolation, it can be used in a novel process for formation of n-on-p junctions. The properties of this n-type converted material are dependent on the condition of the plasma to which it is exposed. This paper investigates the
effect of varying the plasma process parameters in an inductively coupled plasma reactive ion etching (ICPRIE) tool on the
carrier transport properties of the p-to-n type converted material. Quantitative mobility spectrum analysis of variable-field Hall and resistivity data has been used
to extract the carrier transport properties. In the parameter space investigated, the n-type converted layer carrier transport properties and depth have been found to be most sensitive to the plasma process pressure
and temperature. The levels of both RIE and ICP power have also been found to have a significant influence. 相似文献
14.
M. P. Mikhailova E. V. Ivanov K. D. Moiseev Yu. P. Yakovlev E. Hulicius A. Hospodkova J. Pangrac T. Šimeček 《Semiconductors》2010,44(1):66-71
Luminescent characteristics of asymmetric p-InAs/AlSb/InAsSb/AlSb/p-GaSb type II heterostructures with deep quantum wells at the heterointerface are studied. The heterostructures were grown
by metalorganic vapor phase epitaxy. Intense positive and negative luminescence was observed in the range of photon energies
of 0.3–0.4 eV with a forward and reverse bias, respectively. Dependences of the spectra and intensities for positive and negative
luminescence on the pumping current and on the temperature are studied in the range of 77–380 K. It is established that, at
a temperature higher than 75°C, intensity of negative luminescence surpasses that of positive luminescence by 60%. The suggested
heterostructures can be used as lightemitting diodes (photodiodes) with switched positive and negative luminescence in the
mid-IR spectral range of 3–4 μm. 相似文献
15.
The current-voltage characteristic of the p-Ge-n-GaAs heterojunction is experimentally studied under hydrostatic pressure as high as 8 GPa and temperature of 300 K. The baric
coefficient of the edge of the valence band of Ge is calculated using the experimental results. 相似文献
16.
The effects of atomic hydrogen (H) and Br/methanol etching on Hg1−x
Cd
x
Te films were investigated using x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Exposure of an
as-received Hg1−x
Cd
x
Te sample to H + H2 resulted in H-induced TeO2 reduction. The oxide reduction was first order with respect to H + H2 exposure. Exposure to H + H2 after etching the Hg1−x
Cd
x
Te film in a Br/methanol solution induced Hg and C depletion. Hg and C removal was also observed after completely reducing
the TeO2 on the as-received sample. The removal process was hindered by the formation of a Cd-rich overlayer on both etched and unetched
surfaces. 相似文献
17.
Tien-Yu Lo Cheng-Sheng Kao Chung-Chih Hung 《Analog Integrated Circuits and Signal Processing》2009,58(3):197-204
A CMOS transconductor for multi-mode wireless channel selection filter is presented. The linear transconductor is designed
based on the flipped-voltage follower (FVF) circuit and an active resistor to achieve the transconductance tuning. The transconductance
tuning can be obtained by changing the bias current of the active resistor. A third-order Butterworth low-pass filter implemented
with the transconductors was designed by TSMC 0.18-μm CMOS process. The results show that the filter can operate with the
cutoff frequency of 10–20 MHz. The tuning range would be suitable for the specifications of IEEE 802.11 a/b/g/n Wireless LANs
under the consideration of saving chip areas. In the design, the maximum power consumption is 13 mW with the cutoff frequency
of 20 MHz under a 1.8 V supply voltage. 相似文献
18.
R. Wollrab A. Bauer H. Bitterlich M. Bruder S. Hanna H. Lutz K.-M. Mahlein T. Schallenberg J. Ziegler 《Journal of Electronic Materials》2011,40(8):1618-1623
Mainly driven by space applications, mercury cadmium telluride (MCT) focal-plane arrays (FPAs) have been successfully developed
for very long wavelengths (λ
CO > 14 μm at 55 K). For this purpose, the standard n-on-p technology based on MCT grown by liquid-phase epitaxy (LPE) and involving vacancy doping has been modified to extrinsic doping
by a monovalent acceptor. Due to the planar diode geometry obtained by ion implantation, most of the carrier generation volume
is located in the p-type region with a thickness of approximately 8 μm. According to our understanding, the Shockley–Read centers connected with the Hg vacancies are thus significantly reduced.
This situation should lead to longer minority-carrier lifetimes and smaller generation rates under equilibrium conditions,
therefore yielding lower dark current. We indeed observe a reduction by a factor of approximately 15 by using extrinsic doping.
Recent dark current data obtained in the temperature range from 55 K to 85 K on 288 × 384 FPAs with λ
CO(60 K) = 12 μm, either intrinsically or extrinsically doped, corroborate this finding. These data, new results on a 112 × 112 pixel demonstrator
array with λ
CO(55 K) = 14.4 μm, and earlier measurements are compared with Tennant’s Rule 07 established for p-on-n technology. 相似文献
19.
Yu. M. Isaenko 《Journal of Communications Technology and Electronics》2010,55(12):1317-1329
A technique is developed for calculating the electrodynamic characteristics of a filter of H
0n
modes in the case of various configurations of the filter and various combinations of its mechanical and electric parameters.
In numerical computations, the complete set of the filter parameters is taken into account. It is shown that the number of
absorbing elements in the filter can be reduced from three to two and that, simultaneously, the quality characteristics of
the filter can be improved. 相似文献
20.
P. Batoni K. Patel C. C. Burkhart T. K. Shah V. Iyengar M. T. Ahrens S. T. Morton S. M. Bobbio E. B. Stokes 《Journal of Electronic Materials》2007,36(9):1166-1173
In this work we report on the magnetron reactive ion etch (MRIE) technology for gallium nitride (GaN) and aluminum gallium
nitride (Al
x
Ga1−x
N) using dichlorodifluoromethane (CCl2F2), commonly known as halocarbon 12, with etch rates greater than 1,000 and 840 ?/min, respectively. Magnetic confinement of
a very low pressure (10−4 Torr range) radio frequency (RF) discharge generates high-density plasmas, with low sheath voltages at the bounding surfaces,
and very high dissociation of the source gas. Furthermore, the very low pressure of the etch process is characterized by long
mean free paths so that sputtering contamination is reduced. MRIE chemistry has been monitored in situ by means of mass spectroscopy. Finally, we report on the successful fabrication of an indium gallium nitride (In
x
Ga1−x
N) blue light emitting diode (LED), whose fabrication sequence included the MRIE etching of GaN in CCl2F2. 相似文献