Structure and Properties of W and Mo-Subcontact Layers Influenced by Thermal Annealing

1995 ◽  
Vol 403 ◽  
Author(s):  
K. A. Gesheva ◽  
G. Stoyanov ◽  
A. Harizanova ◽  
R. Stefanov
Keyword(s):  
Ohmic Contacts ◽  
Temperature Stability ◽  
Electrochemical Treatment ◽  
Electrical Characteristics ◽  
High Temperature Stability ◽  
Transitional Layer ◽  
Solar Cell Performance ◽  
Heavily Doped ◽  
High Work ◽  
Proper Balance

AbstractOne of the most important problems to solve in order to improve the CdTe solar cell performance is the deposition of stable ohmic contacts. W and Mo with their high work function, high temperature stability and good mechanical properties are prospective materials for contacts to p-CdTe. This paper presents data for the electrophysical characteristics of W or Mo/CdTe and W or Mo/ CdS-CdTe heterostructure systems. W and Mo films are deposited by a W(CO)6 based CVD process at atmospheric pressure and low temperatures (250–300)°C. We emphasize the improvment of the contact properties by developing a transitional layer heavily doped with acceptors. The defects arrangement in the layer should promote the diffusion of such impurities as Cu, P, As etc. A proper balance between the impurities and the defects could be achieved by suitable thermal treatment. Rapid thermal or traditional annealing in different gas atmospheres – N2, Ar or air were applied, followed by chemical or electrochemical treatment. Electrical characteristics measurements and structural studies were performed for CdTe layers as well as for the SnO2 - CdS - CdTe structures

Diffusion of A Deposited GeSe Film in GaAs using Ion-Beam Mixing

1985 ◽  
Vol 45 ◽  
Author(s):  
N. J. Kepler ◽  
N. W. Cheung
Keyword(s):  
Integrated Circuits ◽  
Ohmic Contacts ◽  
Ion Beam ◽  
Threshold Temperature ◽  
Electrical Characteristics ◽  
Electrical Measurements ◽  
Furnace Annealing ◽  
Ion Beam Mixing ◽  
Heavily Doped ◽  
And Diffusion

ABSTRACTIon-beam mixing and rapid thermal annealing (RTA) techniques are used to form shallow and heavily-doped n+ layers in undoped GaAs. RTA reduces surface degradation and improves crystalline quality compared to lengthy thermal cycles, although furnace annealing producesidentical electrical characteristics. Ion-beam mixing has only a small effect on the diffusion of a deposited GeSe film, because the damage created by implantation is repaired during RTA before significant diffusion occurs. We define a threshold temperature representing the onset of significant electrical activation and/or diffusion, and propose a model relating the annealing, activation, and diffusion temperatures for the GeSe/GaAs system. RBS. SIMS, and electrical measurements show that extremely shallow layers with a sheet resistivity as low as 1480/El can be formed in GaAs by diffusion from a GeSe source. This technique has potential application to the formation of shallow ohmic contacts for GaAs integrated circuits.

Investigation of Factors Limiting the High Temperature Stability of W/WC/TaC/SiC Ohmic Contacts to n-type 6H-SiC

2000 ◽  
Vol 640 ◽  
Author(s):  
T. Jang ◽  
B. Odekirk ◽  
L. M. Porter
Keyword(s):  
High Temperature ◽  
Ohmic Contacts ◽  
Temperature Stability ◽  
Atomic Scale ◽  
Specific Contact Resistance ◽  
High Temperature Stability ◽  
Specific Contact ◽  
Operating Limits ◽  
Metallurgical Reactions ◽  
Metal Layers

ABSTRACTThe electrical properties and thermal stability of TaC ohmic contacts with W/WC overlayers were investigated on n-type 6H-SiC (0001) substrates. The specific contact resistance (SCR) was measured after annealing at 600 °C and 1000 °C for 50 ∼ 1000 h. The SCRs (3.0 ∼ 3.6 ×10−5 Ωcm2) of contacts annealed at 600 °C for 1000 h remained constant within the experimental error. Significant increases in the SCR were not observed until the samples were annealed at 1000 °C for several hundred hours.No reaction of the film with the SiC substrate was observed after annealing at 600 °C for 1000 h; however, atomic-scale reactions appeared to be concentrated adjacent to grain boundaries in the reacted film. From Auger depth profiles, it was found that W and WC reacted to form W2C on TaC after annealing.According to SIMS analysis, after annealing at 1000 °C for 600 h, small but measurable changes in the electrical characteristics were associated with O incorporation at the interface between TaC and SiC. Investigation of the W/WC/TaC/SiC interface by TEM indicated that a reaction between the metal layers had occurred, but there was no observed reaction with the SiC substrate. After annealing for 1000 h, substantial changes in the contacts were observed. The findings indicate that both oxidation and metallurgical reactions have important implications on the current operating limits for SiC high temperature devices.

High temperature stability of chromium boride ohmic contacts to p-type 6H-SiC

1998 ◽  
Vol 27 (4) ◽  
pp. 324-329 ◽  
Author(s):  
T. N. Oder ◽  
J. R. Williams ◽  
M. J. Bozack ◽  
V. Iyer ◽  
S. E. Mohney ◽  
...  
Keyword(s):  
High Temperature ◽  
Ohmic Contacts ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Chromium Boride ◽  
P Type

High Electron Mobility Transistors with Optically Processed Refractory Silicide Metallizations: Thermal and Microwave Analysis

1991 ◽  
Vol 240 ◽  
Author(s):  
P. F. Tang ◽  
M. S. Fan ◽  
A. A. Illiadis
Keyword(s):  
High Temperature ◽  
Ohmic Contacts ◽  
Temperature Stability ◽  
High Electron Mobility Transistors ◽  
Input Power ◽  
Junction Temperature ◽  
High Electron ◽  
High Temperature Stability ◽  
High Electron Mobility ◽  
Electron Mobility Transistors

ABSTRACTThe enhanced high temperature gate metallizations consisting of sputtered TiWSi or TiWN were investigated in order to attain high temperature stability at temperatures in excess of 250°C. The TiWN/Au system resulted in a sheet resistance of only 11.5 mΩ/□ while TiWSi/Au resulted in 75.0 mΩ/□. The HEMTs and FETs processed with additional stable ohmic contacts of epitaxial Ge/Pd structures exhibited a stable transconductance of 160 -180 mS/mm at temperatures of 300°C. Thermal analysis indicated the peak junction temperature increase with an input power of 200mW to be less than 18°C at substrate temperature of 60°C.

High Temperature Stability of Oxygen Functionalized Epitaxial Graphene/Metal Contact Interfaces

2013 ◽  
Vol 740-742 ◽  
pp. 145-148
Author(s):  
V. Karthik Nagareddy ◽  
Sandra C. Hernández ◽  
Virginia D. Wheeler ◽  
Luke O. Nyakiti ◽  
Rachael L. Myers-Ward ◽  
...  
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Contact Resistance ◽  
Sheet Resistance ◽  
Temperature Stability ◽  
Epitaxial Graphene ◽  
Metal Contact ◽  
Electrical Characteristics ◽  
Functionalized Graphene ◽  
High Temperature Stability

The electrical characteristics of oxygen functionalized epitaxial graphene and Ti/Au metal contact interfaces were systematically investigated as a function of temperature. As the temperature was increased from 300 K to 673 K, the contact resistance and the sheet resistance decreased by 75% and 33%, respectively. The resistance of oxygen functionalized graphene vs temperature exhibited Arrhenius type behavior with activation energy of 38 meV. The results showed no hysteresis effects in resistance measurements over the temperatures studied here, suggesting the contact interfaces remain stable at high temperatures.

Nickel-Based Germanosilicide of Heavily-Doped SiGe Films for Low Resistance and High-Temperature Stability

2007 ◽  
Vol 124-126 ◽  
pp. 279-282
Author(s):  
A Ram Choi ◽  
Sang Sik Choi ◽  
Jung Hyun Kim ◽  
Sang Hoon Kim ◽  
Kyu Hwan Shim
Keyword(s):  
High Temperature ◽  
Sheet Resistance ◽  
Layer Structure ◽  
Chemical Vapor ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Reduced Pressure ◽  
Resistance Surface ◽  
Pressure Chemical ◽  
Heavily Doped

We have studied thermo-electrical properties for Ni-based germanosilicide to understand the influence of temperature on the evolution of sheet resistance and micro-structures of contacts on heavily-doped SiGe grown by reduced pressure chemical vapor deposition. After the deposition of Ni, Ni/Ti, Ni/Pt films on Si0.83Ge0.17 epi layer and subsequently annealing for silicide reaction, we analyzed sheet resistance, surface roughness and reaction interfaces using four point probe method, scanning probe micrograph and transmission electron microscope. Bi-layer metal structures of Ni/Ti and Ni/Pt were investigated to study feasible use for suppressing inappropriate reaction at interface. It is found that bi-layer structure with thin Pt interlayer presented promising properties for germanosilicide of n+-Si0.83Ge0.17 with low sheet resistance, smooth surface morphology and high temperature stability up to 800 oC.

UNS N06455

Alloy Digest ◽  
1989 ◽  
Vol 38 (1) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Stress Corrosion Cracking ◽  
Temperature Stability ◽  
Heat Treating ◽  
High Ductility ◽  
High Temperature Stability ◽  
Nickel Chromium ◽  
Long Time ◽  
Resistance To Stress

Abstract UNS NO6455 is a nickel-chromium-molybdenum alloy with outstanding high-temperature stability as shown by high ductility and corrosion resistance even after long-time aging in the range 1200-1900 F. The alloy also has excellent resistance to stress-corrosion cracking and to oxidizing atmospheres up to 1900 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-367. Producer or source: Nickel and nickel alloy producers.

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