Characteristics of Pdai Schottky Contacts to n-GaAs

1993 ◽  
Vol 319 ◽  
Author(s):  
T.S. Huang ◽  
J.G. Pang
Keyword(s):  
Depth Profiling ◽  
Schottky Contacts ◽  
Voltage Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barrier Heights ◽  
Β Phase ◽  
Transmission Electron ◽  
Current Voltage ◽  
Thermal Stability Of

AbstractMetallurgical and electrical properties of β-phase PdAl Schottky metallizations on n-GaAs after rapid thermal annealing for 20 s in the temperature range 500-1000°C have been investigated using x-ray diffraction, transmission electron microscopy, Auger depth profiling and current-voltage measurement. The Al-rich contacts were stable up to 900°C, whereas the Pdrich contacts were less stable. The thermal stability of Pd-rich contacts decreased with increasing Pd composition, and interfacial reaction after high temperature annealing resulted in the formation of PdGa compound. The interface between Al-rich PdAI and GaAs substrate was quite sharp even after 900°C anneal. The Schottky barrier heights of Al-rich PdAl contacts increased with annealing temperature. The barrier height enhancement in the annealed Al-rich contacts can be attributed to the thin AlxGal−xAs layer formed at the interface between PdAl and GaAs.

The Study of TiWN Schottky Contacts on n-Ga0.51 In0.49P

1993 ◽  
Vol 300 ◽  
Author(s):  
Edward Y. Chang ◽  
Yeong-Lin Lai ◽  
Kuen-Chyuan Lin ◽  
Chun-Yen Chang ◽  
F. Y. Juang
Keyword(s):  
Schottky Contact ◽  
Rf Magnetron Sputtering ◽  
Schottky Contacts ◽  
Electrical Characteristics ◽  
X Ray Diffraction ◽  
Barrier Heights ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Lattice Matched ◽  
Thermal Stability Of

ABSTRACTThe first study of the TiW nitrides (TiWNx) as the Schottky contact metals to the n type Ga0.51In0 49P has been made. The Ga0.51 In0.49P epitaxial layer was successfully grown on the GaAs substrate by LP-MOCVD to form a lattice-matched heterostructure. The RF-magnetron sputtering system was utilized for the nitride deposition. The thermal stability of the nitride films were studied using rapid thermal annealing (RTA) method. Both the electrical characteristics and the materials characteristics were investigated. The materials properties of the nitride films were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). The TiWNx Schottky contacts demonstrate excellent electrical and physical characteristics, even after high temperature annealing. The barrier heights range from 0.81 to 1.05 eV depending on the content of the nitrogen and the annealing conditions. The XRD and AES results show no indication of interaction at the TiWNX/GaInP interface of both as-deposited and annealed samples. The outstanding characteristics of the contact were attributed to the high bandgap nature of the Ga0.51In0.49P and the incorporation of nitrogen into the TiW films.

Metallurgical and Electrical Characteristics of MoAlx Schottky Contacts to n-GaAs

1992 ◽  
Vol 260 ◽  
Author(s):  
T. S. Huang ◽  
J. G. Peng ◽  
C. C. Lin
Keyword(s):  
Thermal Processing ◽  
Annealing Temperature ◽  
Schottky Diodes ◽  
Schottky Contacts ◽  
Electrical Characteristics ◽  
Interfacial Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barrier Heights ◽  
Current Voltage

ABSTRACTThe interfacial stability, surface morphology and electrical characteristics of MoAlx contacts to n-GaAs have been investigated by using x-ray diffraction, scanning electron microscopy, sheet resistance and current-voltage measurements. The compositions of rf-cosputtered MoAlx films were x = 0.35, 2.7, and 7.0, respectively. The contacts were annealed by rapid thermal processing in the temperature range 500–1000 °C for 20 s. The interfaces of MoAl0.35/GaAs and MoAl2,7/GaAs were stable up to 900 °C, while the interfaces of MoAl7.0/GaAs were less stable and reactions occurred above 800 °C. The variations of sheet resistances and the barrier heights of the Schottky diodes as a function of annealing temperatures can be well correlated to the interfacial stability. The MoAl2.7/n-GaAs diodes exhibited the best stability and were characterized by the highest barrier height (0.98 V) and nearly unit ideality factor (1.11) after annealing at 900 °C. For all thermally stable MoAlx/n-GaAs Schottky diodes, the barrier heights increased with annealing temperature.

Formation and Thermal Stability of Nd0.32Y0.68Si1.7 Layers Formed by Channeled Ion Beam Synthesis

1998 ◽  
Vol 514 ◽  
Author(s):  
M. F. Wu ◽  
A. Vantomne ◽  
S. Hogg ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ion Beam ◽  
Hexagonal Structure ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Good Crystalline Quality ◽  
Ion Beam Synthesis ◽  
Thermal Stability Of

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.

Immobilization of hemoglobin on stable mesoporous multilamellar silica vesicles and their activity and stability

2005 ◽  
Vol 20 (10) ◽  
pp. 2682-2690 ◽  
Author(s):  
Yufang Zhu ◽  
Weihua Shen ◽  
Xiaoping Dong ◽  
Jianlin Shi
Keyword(s):  
Thermal Stability ◽  
Pore Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Practical Applications ◽  
Silica Material ◽  
Transmission Electron ◽  
Mesoporous Support ◽  
Adsorption Desorption ◽  
Thermal Stability Of

A stable mesoporous multilamellar silica vesicle (MSV) was developed with a gallery pore size of about 14.0 nm. A simulative enzyme, hemoglobin (Hb), was immobilized on this newly developed MSV and a conventional mesoporous silica material SBA-15. The structures and the immobilization of Hb on the mesoporous supports were characterized with x-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier transform infrared, ultraviolet-visible spectroscopy, and so forth. MSV is a promising support for immobilizing Hb due to its large pore size and high Hb immobilization capacity (up to 522 mg/g) compared to SBA-15 (236 mg/g). Less than 5% Hb was leached from Hb/MSV at pH 6.0. The activity study indicated that the immobilized Hb retained most peroxidase activity compared to free Hb. Thermal stability of the immobilized Hb was improved by the proctetive environment of MSV and SBA-15. Such an Hb-mesoporous support with high Hb immobilization capacity, high activity, and enhanced thermal stability will be attractive for practical applications.

Modification of clays with styrenic ionic liquid by Synthesis of in-situ Polystyrene Nanocomposite

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Mohammad Galehassadi ◽  
Fatemeh Hosseinzadeh ◽  
Mehrdad Mahkam
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquid ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modified Montmorillonite ◽  
Transmission Electron ◽  
Insitu Polymerization ◽  
Thermal Stability Of

Abstract Nanocomposites of polystyrene (PS) was prepared with new styrenic ionic liquid, N-(4-vinyl benzyl)-(N,N-dimethylamino) pyridinium chloride[VBMAP], surfactants used as organic modifications for the clays. Sodium montmorillonite (Na-MMT) was successfully modified by [VBMAP] to become OMMT through cation exchange technique which is shown by the increase of basalspacing of clay by XRD. The composite material based on polystyrene and organo-modified montmorillonite (OMMT) was prepared by insitu polymerization and characterized. The morphology of the polymer/clay hybrids was evaluated by X-ray diffraction (XRD) ,transmission electron microscopy (TEM) and scanning electron microscopy (SEM), showing good overall dispersion of the clay. The thermal stability of the polymer/clay nanocomposites were enhanced, as evaluated by thermogravimetric analysis.

A new high-temperature inorganic–organic proton conductor: lanthanum sulfophenyl phosphate

2016 ◽  
Vol 70 (3) ◽  
Author(s):  
Ming-Feng Song ◽  
Zhong-Fang Li ◽  
Guo-Hong Liu ◽  
Su-Wen Wang ◽  
Xiao-Yan Yin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Layered Structure ◽  
Proton Conductor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Different Temperatures ◽  
Thermal Stability Of

AbstractLanthanum sulfophenyl phosphate (LaSPP) was synthesized by m-sulfophenyl phosphonic acid and lanthanum nitrate. UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy indicate that the desired product was obtained and its elementary composition and typical layered structure were determined by energy dispersive X-ray spectroscopy and scanning electron microscopy. Transmission electron microscopy (TEM) proved its typical layered structure and X-ray diffraction spectroscopy indicated its good crystallinity and the interlayer distance of about 15.67 Å , which matches the value obtained by TEM (2.0 nm). Thermogravimetry and differential thermal analysis revealed good thermal stability of LaSPP. Proton conductivity of LaSPP was measured at different temperatures and relative humidities (RH), reaching values of 0.123 S cm

500℃ high-temperature reliability of Ni/Nb Ohmic contact on n-type 4H-SiC

2021 ◽  
Author(s):  
Vuong Van Cuong ◽  
Tadashi Sato ◽  
Takamichi Miyazaki ◽  
Tetsuya Meguro ◽  
Seiji Ishikawa ◽  
...  
Keyword(s):  
High Temperature ◽  
Ohmic Contact ◽  
Chemical Compounds ◽  
Etching Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ohmic Behavior ◽  
Transmission Electron ◽  
Current Voltage ◽  
The Stability

Abstract The reliability of Ni/Nb ohmic contact on n-type 4H-SiC at 500℃ was investigated. The current-voltage characteristics showed that, while the Ni(50)/Nb(50)/4H-SiC sample without applying the CF4:O2 etching process degraded just after 25-hour and lost ohmic behavior after 50-hour aging, the Ni(75)/Nb(25)/4H-SiC contact undergone CF4:O2 surface treatment still showed excellent stability after aging for 100 hours at 500℃. Though X-ray diffraction results indicated that the chemical compounds remained stable during the aging process, transmission electron microscopy showed that there was a redistribution of the chemical compounds at the interface of the contact after 500℃ aging. The depth distribution of the elements and energy dispersive X-ray analyses revealed that the contribution of carbon agglomeration at the interface accounted for the degradation of the sample without applying the etching process. Whereas the well-controlled excess carbon atoms of the contact undergone CF4:O2 treatment ensured the stability of this contact when operating at high-temperature ambient.

Structural characterization and thermal stability of W/Si multilayers

1993 ◽  
Vol 8 (10) ◽  
pp. 2600-2607 ◽  
Author(s):  
M. Brunel ◽  
S. Enzo ◽  
M. Jergel ◽  
S. Luby ◽  
E. Majkova ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Layer Thickness ◽  
Thickness Ratio ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Layer Thickness Ratio ◽  
Transmission Electron ◽  
Thermal Stability Of ◽  
Beam Deposition

Tungsten/silicon multilayers with tungsten layers of a thickness of 1–2 nm were prepared by means of electron beam deposition. Their structure and thermal stability under rapid thermal annealing were investigated by a combination of x-ray diffraction techniques and cross-sectional transmission electron microscopy. The crystallization behavior was found to depend on the interdiffusion and mixing at the tungsten/silicon interfaces during deposition as well as during annealing. The as-deposited tungsten/silicon multilayers were amorphous and remained stable after annealing at 250 °C/40 s. Interdiffusion and crystallization occurred after annealing all samples from 500 °C/40 s up to 1000 °C/20 s. By performing the same heat treatment in the tungsten/silicon multilayers, the formation of body-centered cubic W was observed with a layer thickness ratio δW/δsi = 1, whereas tetragonal WSi2 was detected in tungsten/silicon multilayers with a layer thickness ratio of δw/δsi ∼0.25. This dependence of the crystallization products on the layer thickness ratio δw/δsi originates from the different phenomena of interdiffusion and mixing at the tungsten/silicon interfaces. The possible formation of bcc tungsten as a first stage of crystallization of tungsten-silicon amorphous phase, rich in tungsten, is discussed.

Structural and Electrical Characterization of TiB2/TiSi2 Bilayer Barrier Structure

1996 ◽  
Vol 441 ◽  
Author(s):  
G. Sade ◽  
J. Pelleg ◽  
A. Grisaru
Keyword(s):  
Diffusion Barrier ◽  
Vacuum Annealing ◽  
Schottky Diodes ◽  
Electrical Characterization ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Current Voltage ◽  
Thermal Stability Of

AbstractThe TiB2/TiSi2 bilayer is considered as a diffusion barrier in metallization system with Cu. The TiSi2 sublayer serves as a contact and also as an additional diffusion barrier against boron, which outdiffuses from TiB2 at high temperature annealing. The attempts to form TiSi2 by vacuum annealing of TiB2/Ti film, which was obtained by co-sputtering from elemental targets are described. The composition and the structure of the films were analyzed by Auger electron spectroscopy (AES), X-ray diffraction (XRD) and high-resolution cross-sectional TEM (HRXTEM). The Cu/TiB2/(Ti-Si)/n-Si contacts were investigated using current-voltage (I–V) on Schottky diode structures, which were prepared on n-type Si (100). The thermal stability of the TiB2/(Ti-Si) barrier was studied by structural and electrical analysis.It was observed that the lowest sheet resistance of 5.1 Ω/‪ was obtained after 850 °C annealing for 30 min, however the resulting Ti-Si layer is practically still amorphous and contains only a very small fraction of C54 TiSis in the form of microcrystallites. This layer also contained Ti5Si3 as indicated by XRD. The barrier height of Cu/TiB2/(Ti-Si)/n-Si Schottky diodes is ˜0.6 V and it does not show significant changes in the range 400–700 °C. Electrical monitoring is a very effective tool to detect deterioration of the barrier. No penetration is observed by AES at 700 °C, while the I–V curve shows changes in properties.

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