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.

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.

Study of the Thermal Stability of the Schottky Contacts on GaInP Grown by LP-MOCVD

1992 ◽  
Vol 282 ◽  
Author(s):  
Edward Y. Chang ◽  
Yeong-Lin Lai ◽  
Kuen-Chyuan Lin ◽  
Chun-Yen Chang ◽  
F. Y. Juang
Keyword(s):  
Thermal Stability ◽  
Single Layer ◽  
Schottky Contacts ◽  
Metal Contacts ◽  
Barrier Heights ◽  
Annealing Conditions ◽  
Metal Silicides ◽  
Lattice Matched ◽  
Thermal Stability Of ◽  
Selection Of

ABSTRACTThermal stability of the Schottky contacts on Ga0.51In0.49P has been made. The Ga0.51In0.49P epitaxial layer was successfully grown on the GaAs substrate by LP-MOCVD to form a lattice-matched heterostructure. In this paper, materials aspects of the Ga0.51In0.49P layers were characterized and thermal stability of three different types of films, including single-layer metal (Pt, Ni, Pd, Au, Co, Mo, W, Cr, Ti, Al, Ta, and In), metal silicides (WSi2, W5Si3, PtSi, and Pt2i), and TiW nitrides (TiWNx ) as the Schottky contacts materials on Ga0.51In0.49P were studied. Due to the high bandgap nature of Ga0.51In0.49P, the Schottky contacts on Ga0.51In0.49P demonstrate good characteristics. The barrier heights range from 0.79 to 1.19 eV depending on the selection of the materials and the annealing conditions. For single-metal contacts, Pt film shows the best thermal stability, the barrier height of 1.09 eV and the ideality factor of 1.06 were obtained for the Pt Schottky diode with furnace annealing at 500 °C for 30 min. For refractory compound films, the TiWNx film shows the best thermal stability. The TiWNx Schottky contacts demonstrate excellent electrical as well as physical characteristics, even after high temperature annealing at 850°C.

Microstructure studies of tungsten silicide schottky contacts on Gaas

1987 ◽  
Vol 45 ◽  
pp. 328-329
Author(s):  
Yih-Cheng Shih ◽  
E. L. Wilkie
Keyword(s):  
Thermal Stability ◽  
Field Effect Transistors ◽  
Schottky Contact ◽  
Schottky Contacts ◽  
Excellent Thermal Stability ◽  
Barrier Heights ◽  
Gaas Substrates ◽  
Film Adhesion ◽  
Threshold Voltages ◽  
Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

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.

Comparison of Electrical Characteristics of 4H-SiC(0001) and (000-1) Schottky Barrier Diodes

2006 ◽  
Vol 527-529 ◽  
pp. 927-930 ◽  
Author(s):  
Tomonori Nakamura ◽  
Toshiyuki Miyanagi ◽  
Isaho Kamata ◽  
Hidekazu Tsuchida
Keyword(s):  
Schottky Barrier ◽  
Annealing Temperature ◽  
Schottky Contact ◽  
Schottky Contacts ◽  
Electrical Characteristics ◽  
Schottky Barrier Diodes ◽  
Barrier Heights ◽  
Excess Current ◽  
Low Leakage ◽  
Low Leakage Current

We compared the electrical characteristics of 4H-SiC(0001) and (000-1) Schottky barrier diodes (SBDs), and derived the Schottky barrier heights (Hbs) of Ta, W, Mo, and Pd on {0001}. We investigated the annealing temperature dependence of Hbs in Mo and the W Schottky contacts for (0001) and (000-1). The Hbs are increased by annealing, except for the W Schottky contact on (0001). The yields of 0.25 cm2 as-deposited Mo-SBDs were 93.3% for (0001) and 71.1% for (000-1), respectively. We also demonstrated over 1 cm2 (0001) as-deposited Mo-SBD with a low leakage current, an excellent ideality factor, and no excess current, encouraging the enlargement of the active area in the SBD.

WSix formation in W–Si multilayers

1987 ◽  
Vol 65 (8) ◽  
pp. 868-871 ◽  
Author(s):  
S. Eicher ◽  
R. A. Bruce
Keyword(s):  
Schottky Contact ◽  
Multilayered Structure ◽  
Schottky Contacts ◽  
Thin Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicon Thin Films ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Effect Transistor

The formation of WSix phases from multiple thin layers of W and Si was investigated. Tungsten and silicon thin films of ~5 nm thickness were deposited sequentially onto GaAs substrates by dc magnetron sputtering from elemental targets. The total film thickness was ~300 nm. The W and Si layer thickness, and thus the overall composition of the films, was controlled by adjusting the power applied to the two sputtering targets. The films examined in this work had nominal compositions in the range WSi2–WSi0.48.The multilayered structure was subjected to rapid thermal annealing at 900 °C. The extent of the reaction, the grain size, and the crystal structure of the silicides were determined using transmission electron microscopy and X-ray diffraction. For WSix films with [Formula: see text], the silicides had the βW structure and were relatively large grained, ~450 nm, while for x > 0.52, the film contained the W5Si3 phase and consisted of grains ~45 nm in diameter.Schottky contacts were of good quality for [Formula: see text], with a barrier height (ϕ) of 0.7 V and an ideality factor (n) of 1.15. Schottky contacts with higher silicon concentrations were poor.The WSix (x = 0.52) Schottky contact has been successfully incorporated into a self-aligned gate field-effect transistor.

Temperature-Dependent Electrical Characteristics of Ag Schottky Contacts to Differently Grown O-Polar Bulk ZnO

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Hogyoung Kim ◽  
Ahrum Sohn ◽  
Yunae Cho ◽  
Dong-Wook Kim
Keyword(s):  
Electron Transport ◽  
Electrical Properties ◽  
Schottky Contact ◽  
Thermionic Emission ◽  
Schottky Contacts ◽  
Current Transport ◽  
Electrical Characteristics ◽  
Temperature Dependent ◽  
Barrier Heights ◽  
Two Samples

The temperature-dependent electrical properties of Ag Schottky contacts to differently grown O-polar bulk ZnO single crystals were comparatively investigated in the temperature range of 100–300 K. Schottky contact to hydrothermal ZnO produced the higher barrier heights (lower ideality factors) than that of pressurized melt-grown ZnO. The modified Richardson plots for two samples produced the larger Richardson constant compared to the theoretical value of 32 A cm−2 K−2 for n-type ZnO, indicating that the inhomogeneous barrier height with the thermionic emission (TE) model could not explain the current transport. The conductive accumulation layers on the ZnO surfaces might not be removed effectively for two samples, which degraded the rectifying characteristics. The different electron transport characteristics between hydrothermal and pressurized melt-grown ZnO could be explained by the different degree of Ag-O formation at the interface.

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.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

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.

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