Characterization of Ti/TiN and TiN Conductive Layer for High Temperature MEMS Devices

2005 ◽  
Vol 872 ◽  
Author(s):  
Peter Lange ◽  
Birger Ohlsen ◽  
Sebastian Puls ◽  
Joerg Syre
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Elevated Temperature ◽  
Mechanical Stability ◽  
Fast Response ◽  
Conductive Layer ◽  
Mems Devices ◽  
Thermal Isolation ◽  
Effects Of Temperature

AbstractThe effects of temperature on micro heaters made of Ti/TiN stacks and pure TiN layers on bulk micromachined membranes have been studied. Ti/TiN stacks show a thermal stability up to 380°C, beyond that temperature an enhanced interaction within the stack and/or with adjacend layers leads to a degradation of the resistance. The pure TiN layers withstand temperatures up to 600 °C, this limitation is only given by the mechanical stability of the membran stack, which is destroyed beyond this temperature. These layers are suitable for sensors in which an elevated temperature provided by heating lines on a membran for thermal isolation and fast response is necessary for functionality.

High Thermal Stability of Mo/Si3N4/Mo/Si3N4/SiO2 Multilayer Solar Selective Coatings

2015 ◽  
Vol 1102 ◽  
pp. 67-71 ◽  
Author(s):  
Rui Hua Yang ◽  
Jin Yang Liu ◽  
Li Mei Lin ◽  
Fa Chun Lai ◽  
Yan Qu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Multilayer Structure ◽  
High Thermal Stability ◽  
Solar Absorptance ◽  
Selective Coating ◽  
Thermal Emittance ◽  
Quartz Substrates ◽  
Thermal Stability Of

In terms of good optical properties and high thermal stability, Mo/Si3N4/Mo/Si3N4/SiO2 coatings based on metal/dielectric multilayer structure were adapted to the solar selective coating at high operating temperatures. The coatings exhibited high solar absorptance in the range of 0.924 ~ 0.936 and low thermal emittance of 0.114 ~ 0.118. The coatings deposited on quartz substrates were thermally stable up to 625 °C in air for 2 h, while they were degraded at 650 °C from the characterization of the absorptance and emittance. The degradation of the coatings was mainly due to the oxidation of molybdenum in air, which was confirmed by Raman spectroscopy. Compared with the thermal stability in air, the coatings were much more stable in vacuum under high temperature. The remarkable thermal stability of the Mo/Si3N4/Mo/Si3N4/SiO2 coatings in air and in vacuum makes them suitable to be applied at high temperature applications.

scholarly journals Elevated Temperature, In Situ Micromechanical Characterization of a High Temperature Ternary Shape Memory Alloy

JOM ◽  
2015 ◽  
Vol 67 (12) ◽  
pp. 2908-2913 ◽  
Author(s):  
J. M. Wheeler ◽  
C. Niederberger ◽  
R. Raghavan ◽  
G. Thompson ◽  
M. Weaver ◽  
...  
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Micromechanical Characterization

scholarly journals Further thermal characterization of an aspartate aminotransferase from a halophilic organism

1994 ◽  
Vol 298 (2) ◽  
pp. 465-470 ◽  
Author(s):  
F J G Muriana ◽  
M C Alvarez-Ossorio ◽  
A M Relimpio
Keyword(s):  
Thermal Stability ◽  
Aspartate Aminotransferase ◽  
Thermal Inactivation ◽  
Hydrophobic Interactions ◽  
Thermal Characterization ◽  
Haloferax Mediterranei ◽  
First Order Kinetics ◽  
Effects Of Temperature ◽  
Thermal Stability Of

Aspartate aminotransferase (AspAT, EC 2.6.1.1) from the halophilic archaebacterium Haloferax mediterranei was purified [Muriana, Alvarez-Ossorio and Relimpio (1991) Biochem. J. 278, 149-154] and further characterization of the effects of temperature on the activity and stability of the halophilic AspAT were carried out. The halophilic transaminase is most active at 65 degrees C and stable at high temperatures, under physiological or nearly physiological conditions (3.5 M KCl, pH 7.8). Thermal inactivation (60-85 degrees C) of the halophilic AspAT followed first-order kinetics, 2-oxoglutarate causing a shift of the thermal inactivation curves to higher temperatures. The salt concentration affected the thermal stability of the halophilic transaminase at 60 degrees C, suggesting that disruption of hydrophobic interactions may play an important role in the decreased thermal stability of the enzyme.

Microstructural characterization of a Cr2Nb-Nb(Cr) microlaminate composite

1994 ◽  
Vol 52 ◽  
pp. 706-707
Author(s):  
M. Larsen ◽  
R. G. Rowe ◽  
D. W. Skelly
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Metal Layer ◽  
Intermetallic Layer ◽  
Weight Ratio ◽  
Microstructural Characterization ◽  
Aircraft Engine ◽  
Intrinsic Defect ◽  
Lamellar Thickness

The thrust to weight ratio of an aircraft engine is limited by the density and elevated temperature performance of high temperature structural materials. Many material systems are currently under investigation as potential next generation engine materials. Microlaminate composites consisting of alternating layers of a ductile refractory metal for toughening and a high temperature intermetallic compound for elevated temperature strength have applicability in aircraft engine turbines. The lamellar thickness of such a composite must be small because the intrinsic defect size, a crack across the intermetallic layer, will be controlled by the intermetallic layer thickness. The microstructural characterization of a Cr2Nb-Nb(Cr) microlaminate composite produced by Magnetron® sputtering was carried out by cross-sectional TEM. Both the as-deposited composite and one heat treated at 1200°C for two hours were examined.Figure 1 shows a micrograph of the as-deposited composite. The metal and intermetallic layers are 2um thick. The metal layer has a composition in atomic percent of 95% Nb and 5% Cr.

Electrical Characterization of Large Area 800 V Enhancement-Mode SiC VJFETs for High Temperature Applications

2009 ◽  
Vol 615-617 ◽  
pp. 715-718 ◽  
Author(s):  
Andrew Ritenour ◽  
Volodymyr Bondarenko ◽  
Robin L. Kelley ◽  
David C. Sheridan
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Threshold Voltage ◽  
Room Temperature ◽  
Electrical Characterization ◽  
Saturation Current ◽  
Large Area ◽  
Enhancement Mode ◽  
High Temperature Operation

Prototype 800 V, 47 A enhancement-mode SiC VJFETs have been developed for high temperature operation (250 °C). With an active area of 23 mm2 and target threshold voltage of +1.25 V, these devices exhibited a 28 m room temperature on-resistance and excellent blocking characteristics at elevated temperature. With improved device packaging, on-resistance and saturation current values of 15 m and 100 A, respectively, are achievable.

scholarly journals Thermal Stability of Retained Austenite and Properties of A Multi-Phase Low Alloy Steel

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 807 ◽  
Author(s):  
Zhenjia Xie ◽  
Lin Xiong ◽  
Gang Han ◽  
Xuelin Wang ◽  
Chengjia Shang
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Alloy Steel ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Volume Fraction ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Multi Phase ◽  
Thermal Stability Of

In this work, we elucidate the effects of tempering on the microstructure and properties in a low carbon low alloy steel, with particular emphasis on the thermal stability of retained austenite during high-temperature tempering at 500–700 °C for 1 h. Volume fraction of ~14% of retained austenite was obtained in the studied steel by two-step intercritical heat treatment. Results from transmission electron microscopy (TEM) and X-ray diffraction (XRD) indicated that retained austenite had high thermal stability when tempering at 500 and 600 °C for 1 h. The volume fraction was ~11–12%, the length and width remained ~0.77 and 0.21 μm, and concentration of Mn and Ni in retained austenite remained ~6.2–6.6 and ~1.6 wt %, respectively. However, when tempering at 700 °C for 1 h, the volume fraction of retained austenite was decreased largely to ~8%. The underlying reason could be attributed to the growth of austenite during high-temperature holding, leading to a depletion of alloy contents and a decrease in stability. Moreover, for samples tempered at 700 °C for 1 h, retained austenite rapidly transformed into martensite at a strain of 2–10%, and a dramatic increase in work hardening was observed. This indicated that the mechanical stability of retained austenite decreased.

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