Cycling Times of Thin-Film NiTi on Si

1991 ◽  
Vol 246 ◽  
Author(s):  
A. Peter Jardine

AbstractThe thermo-mechanical properties of NiTi are well known for bulk material although its deposition and utilization as a thin film are still in their earliest stages. The deposition of thin-films of Shape Memory Effect NiTi onto Si(100) wafers offers several advantages over bulk NiTi, including fast response times and comparitively large transformation forces, and so is a promising candidate as a micro-actuator for MicroElectroMechanical (MEMS) systems as well as in strain measurements. The response time for a variety of NiTi layers were modelled under different boundary conditions and show response times similar to the acoustic velocities for one micron thick NiTi.

1993 ◽  
Vol 311 ◽  
Author(s):  
A.Peter Jardine ◽  
Peter G. Mercado

ABSTRACTAlthough the thermo-mechanical properties of NiTi are well known for bulk material, its deposition and utilization as a thin film are still in their earliest stages of research. The deposition of thin-films of Shape Memory Effect NiTi onto Si(100) wafers offers several advantages over bulk NiTi, including fast response times and comparatively large transformation forces. This has made it a promising candidate material as micro-actuators for Micro-Electro-Mechanical (MEMS) systems as well as for strain measurements. The cycling time for actuation was measured for a 20 μm free standing NiTi thin film cantilever. It was demonstrated that cycling frequencies of up to 50 Hz are achievable.


Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 119
Author(s):  
Anastasiia Tukmakova ◽  
Ivan Tkhorzhevskiy ◽  
Artyom Sedinin ◽  
Aleksei Asach ◽  
Anna Novotelnova ◽  
...  

Terahertz (THz) filters and detectors can find a wide application in such fields as: sensing, imaging, security systems, medicine, wireless connection, and detection of substances. Thermoelectric materials are promising basis for THz detectors’ development due to their sensitivity to the THz radiation, possibility to be heated under the THz radiation and produce voltage due to Seebeck effect. Thermoelectric thin films of Bi-Sb solid solutions are semimetals/semiconductors with the band gap comparable with THz energy and with high thermoelectric conversion efficiency at room temperature. Detecting film surface can be transformed into a periodic frequency selective surface (FSS) that can operate as a frequency filter and increases the absorption of THz radiation. We report for the first time about the simulation of THz detector based on thermoelectric Bi-Sb thin-filmed frequency-selective surface. We show that such structure can be both detector and frequency filter. Moreover, it was shown that FSS design increases not only a heating due to absorption but a temperature gradient in Bi-Sb film by two orders of magnitude in comparison with continuous films. Local temperature gradients can reach the values of the order of 100 K·mm−1. That opens new perspectives for thin-filmed thermoelectric detectors’ efficiency increase. Temperature difference formed due to THz radiation absorption can reach values on the order of 1 degree. Frequency-transient calculations show the power dependence of film temperature on time with characteristic saturation at times around several ms. That points to the perspective of reaching fast response times on such structures.


1997 ◽  
Vol 471 ◽  
Author(s):  
J. Liu ◽  
D. C. Morton ◽  
M. R. Miller ◽  
Y. Li ◽  
E. W. Forsythe ◽  
...  

ABSTRACTZn2SiO4:Mn thin films were deposited and studied as thin film phosphors for flat panel cathodoluminescent displays. Crystallized films with improved electrical conductivity were obtained after conventional and rapid thermal annealings in a N2 environment at 850Xy11100 °C for 0.25 to 60 minutes. A maximum cathodoluminescent efficiency of 1.3 Lm/W was achieved under dc excitation at 1500 volts. The luminescent emission from these thin films was peaked around 525 nm. The decay time of these films was controlled in the range of 2 to 10 ms by varying the deposition and annealing parameters. The fast response time of these thin films overcomes the long decay limitation of the Zn2SiO4:Mn powder phosphor in practical display applications.


2011 ◽  
Vol 1288 ◽  
Author(s):  
Rashmi Menon ◽  
K. Sreenivas ◽  
Vinay Gupta

ABSTRACTZinc Oxide (ZnO), II-VI compound semiconductor, is a promising material for ultraviolet (UV) photon sensor applications due to its attractive properties such as good photoconductivity, ease processing at low temperatures and excellent radiation hardness. The rf magnetron sputtering is a suitable deposition technique due to better control over stoichiometry and deposition of uniform film. Studies have shown that the presence of surface defects in ZnO and subsequently their passivation are crucial for enhanced photo-response characteristics, and to obtain the fast response speed. Worldwide efforts are continuing to develop good quality ZnO thin films with novel design structures for realization of an efficient UV photon sensor. In the present work, UV photon sensor is fabricated using a ZnO thin films deposited by rf magnetron sputtering on the corning glass substrate. Photo-response, (Ion/Ioff) of as-grown ZnO film of thickness 100 nm is found to be 3×103 with response time of 90 ms for UV intensity of 140 μW/cm2 (λ = 365 nm). With irradiation on ZnO thin film by pulsed Nd:YAG laser (forth harmonics 266 nm), the sensitivity of the UV sensor is found to enhance. The photo-response increases after laser irradiation to 4x104 with a fast response speed of 35 ms and attributed to the change in surface states and the native defects in the ZnO thin film. Further, enhancement in the ultraviolet (UV) photo-response (8×104) of detector was observed after integrating the nano-scale islands of Sn metal on the surface of laser irradiated ZnO thin film.


1988 ◽  
Vol 3 (5) ◽  
pp. 931-942 ◽  
Author(s):  
T. P. Weihs ◽  
S. Hong ◽  
J. C. Bravman ◽  
W. D. Nix

The mechanical deflection of cantilever microbeams is presented as a new technique for testing the mechanical properties of thin films. Single-layer microbeams of Au and SiO2 have been fabricated using conventional silicon micromachining techniques. Typical thickness, width, and length dimensions of the beams are 1.0,20, and 30 μm, respectively. The beams are mechanically deflected by a Nanoindenter, a submicron indentation instrument that continuously monitors load and deflection. Using simple beam theory and the load-deflection data, the Young's moduli and the yield strengths of thin-film materials that comprise the beams are determined. The measured mechanical properties are compared to those obtained by indenting similar thin films supported by their substrate.


2005 ◽  
Vol 908 ◽  
Author(s):  
Kristoffer Meinander ◽  
Tina Clauss ◽  
Kai Nordlund

AbstractMechanical properties of thin films grown by nanocluster deposition are highly dependent on the energy at which the clusters are deposited. Using molecular dynamics computer simulations we have quantitatively studied variations in the properties of copper thin films grown by deposition of Cu nanoclusters, at energies ranging from 5 meV to 10 eV per cluster atom, on a Cu (100) substrate.


1994 ◽  
Vol 356 ◽  
Author(s):  
H. Deng ◽  
V. R. Inturi ◽  
J. A. Barnard

AbstractMechanical and tribological properties of soft magnetic thin films with high permeability and low coercivity are very important for the application of these films in high-density recording heads. This paper reports our experimental observations on these important properties of FeTaN thin film head materials. Hardness(H) and Young’s modulus(E) for FeTaN sputtered films were determined by nanoindentation. Wear resistance of these films against commercial magnetic tapes was measured with a sphere-on-flat wear tester. The experimental results indicate that the FeTa films can be hardened when nitrogen is introduced. It was found in this study that the thermal stability of the mechanical properties such as hardness of thin films containing nitrogen is better than that of the film without nitrogen. However, our experiments also revealed that the wear resistance of FeTaN films decreases when the concentration of nitrogen increases and the hardness of the worn surface at a wear scar is lower than that of the unworn surface.


Author(s):  
Zhaohui Shan ◽  
Suresh K. Sitaraman

Titanium thin films have been widely used in microelectronics due to their good adhesion to substrates, such as Silicon wafer and Quartz. However, mechanical behavior of Titanium thin films has not been well characterized. This paper presents a methodology that combines the nanoindentation technique and finite element modeling to characterize the mechanical (elastic and plastic) properties of thin film with its application on Titanium thin film deposited on silicon substrate. The results show that the elastic properties (Young’s modulus) of the Titanium thin film does not change much from the bulk Titanium, and the plastic properties (yield stress and strain hardening exponent) of the Titanium thin film are higher than those of bulk Titanium. This method is also applicable for the study of mechanical properties of other thin films and small volume materials.


1992 ◽  
Vol 7 (6) ◽  
pp. 1553-1563 ◽  
Author(s):  
Martha K. Small ◽  
W.D. Nix

Since its first application to thin films in the 1950's the bulge test has become a standard technique for measuring thin film mechanical properties. While the apparatus required for the test is simple, interpretation of the data is not. Failure to recognize this fact has led to inconsistencies in the reported values of properties obtained using the bulge test. For this reason we have used the finite element method to model the deformation behavior of a thin film in a bulge test for a variety of initial conditions and material properties. In this paper we will review several of the existing models for describing the deformation behavior of a circular thin film in a bulge test, and then analyze these models in light of the finite element results. The product of this work is a set of equations and procedures for analyzing bulge test data that will improve the accuracy and reliability of this technique.


Author(s):  
Jiatong Liu ◽  
Ken Suzuki ◽  
Hideo Miura

In a three-dimensional (3D) packaging systems, the interconnections which penetrate stacked silicon chips have been employed. Such interconnection structure is called TSV (Through Silicon Via) structure, and the via is recently filled by electroplated copper thin film. The electroplated copper thin films often consist of fine columnar grains and porous grain boundaries with high density of defects which don’t appear in conventional bulk material. This unique micro texture has been found to cause the wide variation of physical and chemical properties of this material. In the TSV structure, the shrinkage of the copper thin film caused by thermal deformation and recrystallization of the unique texture during high-temperature annealing is strictly constrained by surrounding rigid Si and thus, high tensile residual stress remains in the thin film after thermal annealing. High residual stress should give rise to mechanical fracture of the interconnections and the shift of electronic function of thin film devices formed in Si. Therefore, the residual stress in the interconnections should be minimized by controlling the appearance of the porous boundaries during electroplating for assuring the longterm reliability of the interconnections. As the lattice mismatch between Cu and its barrier film (Ta) is as larger as 18%, which is the main reason for the fine columnar structures and porous grain boundaries, it is necessary to control the underlayer crystallinity to improve the crystallinity of electroplated copper thin films. In this study, the effective method for controlling the crystallinity of the underlayer was investigated by improving the atomic configuration in the electroplated copper thin film. The result showed that by controlling the crystallinity of underlayer, crystallinity of electroplated copper thin films can be improved, the mechanical properties of thin films was improved and thus, stability and lifetime of electroplated copper interconnections can be improved.


Sign in / Sign up

Export Citation Format

Share Document