Stable Ohmic Contacts on GaAs and GaN Devices for High Temperatures

2002 ◽  
Vol 743 ◽  
Author(s):  
A. Piotrowska ◽  
E. Kaminska ◽  
A. Barcz ◽  
K. Golaszewska ◽  
H. Wrzesinska ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
High Temperatures ◽  
Ohmic Contacts ◽  
High Temperature Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

ABSTRACTWe have studied thermal stability of Nb and NbN contacts to GaAs and GaN by x-ray diffraction and SIMS, and demonstrated their excellent behaviour under high temperature annealing. GaAs/Nb and GaAs/NbN contacts are stable up to 800°C and 900°C, respectively while GaN/NbN and GaN/Nb/NbN remain stable up to 1000°C.

Investigation on the Thermal Stability of the Compounds Y3Fe29-xCrx

2013 ◽  
Vol 820 ◽  
pp. 71-74
Author(s):  
Xiao Hua Wang ◽  
Wei He ◽  
Ling Min Zeng
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Single Phase ◽  
Binary Compound ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Transition Elements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

Binary compound Y3Fe29cannot be directly formed by rare earth Y and Fe and the third element M (non-iron transition elements) must be introduced to form ternary compound Y3(Fe,M)29. In this work, six alloys with compositions of the Y3Fe29-xCrx(x=1,2,3,4,5,6) were prepared and investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and differential thermal analysis (DTA). The study on the thermal stability of these compounds points to that the compoundY3(Fe,Cr)29is a high temperature phase and exists above 1100K. The alloys with single-phase of Y3(Fe,Cr)29was decomposed into Y2(Fe,Cr)17and Y(Fe,Cr)12annealed at high temperature 1100K.

Improvement of Thermal Stability of ZrB2/Si3N4 Coatings as High-Temperature Solar Selective Absorbers

2014 ◽  
Vol 521 ◽  
pp. 581-585
Author(s):  
Yao Ming Sun ◽  
Xiu Di Xiao ◽  
Guan Qi Chai ◽  
Gang Xu ◽  
Bin Xiong ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
High Temperature ◽  
Substrate Temperature ◽  
Bias Voltage ◽  
X Ray Diffraction ◽  
Substrate Bias Voltage ◽  
X Ray ◽  
Deposition Parameters ◽  
Thermal Stability Of

ZrB2 thin films were prepared by DC magnetron sputtering technique. The microstructure, thermal stability and optical properties of thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectrophotometer. The compactness of ZrB2 thin films was studied to improve the thermal stability by optimizing the deposition parameters. The compactness and thermal stability of the coatings were improved with the increase of substrate temperature. However, these properties of the coatings were enhanced firstly and then weakened with the increase of substrate bias voltage. The selectivity of sample deposited at high substrate temperature and suitable bias voltage degraded slightly after annealing at 500 °C/100 h in air. This provided a new way to improve the thermal stability of high-temperature solar selective absorber.

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.

Influence of High Temperature Annealing on Microstructure Evolution of Ni-24Fe-14Cr-8Mo Superalloy

2021 ◽  
Vol 904 ◽  
pp. 117-123
Author(s):  
Yi Cui ◽  
Yun Fei Zhang ◽  
Yan Guang Han ◽  
Da Lv
Keyword(s):  
High Temperature ◽  
Microstructure Evolution ◽  
Testing Machine ◽  
Aging Treatment ◽  
Growth Patterns ◽  
High Temperature Annealing ◽  
Rockwell Hardness ◽  
Hardness Testing ◽  
X Ray Diffraction ◽  
X Ray

The effect of high temperature annealing on microstructure evolution of Ni-24Fe-14Cr-8Mo alloy was investigated through Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Rockwell Hardness Testing Machine. Three kinds of grain growth patterns were found at different annealing temperatures due to carbides precipitation and dissolution. After a combination of high temperature annealing and aging treatment, the hardness versus time curves performed a parabolic pattern. The highest hardness was achieved under 1070°C/60 minutes treatment, and the desirable annealing time should be 60 minutes to 90 minutes.

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