Effect of Substrate Temperature on the Shape Memory Behavior of Ti-Ni-Cu Ternary Alloy Sputtered Films

The purpose of this work is to establish a deposition process of Ti-Ni-Cu films showing shape memory effect in the as-deposited state. 5-µm-thick Ti50Ni35Cu15 films have been deposited onto thermally oxidized (001) Si wafer by triple-source dc magnetron sputtering at various substrate temperatures. Their shape memory behavior were characterized by XRD, DSC measurements and thermal cycling tests under various constant tensile stresses. We have confirmed that crystalline films can be grown directly when the substrate temperature exceeds 400°C. The films deposited at higher than 450°C showed thermoelastic martensitic transformation and their Ms temperature slightly increased with increasing substrate temperature. Since their Ms temperature were found to be higher than 30°C, they can be used as an actuator at RT. These films were also found to have higher critical stress against plastic deformation than the post-deposition crystallized films. We have also tried to fabricate a prototype of micro-actuator and to characterize their actuation behavior and have confirmed that TiNiCu/SiO2 double layered diaphragm showed an actuation response to a pulsed current of more than 100Hz.

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Observations on the growth of barium bismuth oxide thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120783 ◽

1992 ◽

Vol 50 (1) ◽

pp. 76-77

Author(s):

M G. Norton ◽

E.S. Hellman ◽

E.H. Hartford ◽

C.B. Carter

Keyword(s):

Substrate Temperature ◽

Deposition Process ◽

Nucleation Layer ◽

Second Stage ◽

Device Applications ◽

High Transition ◽

Substrate Temperatures ◽

Oriented Material ◽

Barium Bismuth ◽

Superconductor Device

The bismuthates (for example, Ba1-xKxBiO3) represent a class of high transition temperature superconductors. The lack of anisotropy and the long coherence length of the bismuthates makes them technologically interesting for superconductor device applications. To obtain (100) oriented Ba1-xKxBiO3 films on (100) oriented MgO, a two-stage deposition process is utilized. In the first stage the films are nucleated at higher substrate temperatures, without the potassium. This process appears to facilitate the formation of the perovskite (100) orientation on (100) MgO. This nucleation layer is typically between 10 and 50 nm thick. In the second stage, the substrate temperature is reduced and the Ba1-xKxBiO3 is grown. Continued growth of (100) oriented material is possible at the lower substrate temperature.

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Electrical Properties of Pulsed Laser Deposited ZnO Thin Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.67.121 ◽

2009 ◽

Vol 67 ◽

pp. 121-125

Author(s):

Chattopadhyay Sourav ◽

Kumar Nath Tapan

Keyword(s):

Thin Films ◽

Surface Morphology ◽

Substrate Temperature ◽

Hall Mobility ◽

Pulsed Laser ◽

Deposition Process ◽

Zno Thin Films ◽

Zno Films ◽

Visible Absorption ◽

Substrate Temperatures

Epitaxial Single-crystal ZnO thin films have been grown on c-plane (0001) sapphire by Pulsed Laser Deposition process at different substrate temperatures (300 – 800 °C) with 10-1 mbar oxygen pressure. The thicknesses of the films have been varied by varying number of pulses with a repetition rate of 10 pulse/sec. It is found that the sheet resistivity of ZnO thin films grown on c-plane sapphires are in the order of 10-2 Ω-cm and it increases with increasing substrate temperatures and film thickness. The carrier concentrations and Hall mobility are found to be in the order of 1017 cm-3 and ~195 cm2/V-s, respectively. The Hall mobility slightly decreases with increase of substrate temperature and thickness of the films. It is also found that the ZnO films are structurally uniform and well oriented with perfect wurtzite structure with c/a ratio 5.1. We have also deposited non-epitaxial ZnO films on (100) p-Silicon substrates at the same conditions. From HR FE-SEM micrographs, surface morphology of ZnO films grown at lower substrate temperature are found to be uniform compared to the films grown at higher temperatures showing non-uniformity and misoriented wurtzite structures. However, the surface morphology of ZnO flims grown epitaxially on (0001) sapphire are found to be more uniform and it does not change much with growth temperature. The resistivity of the films grown on p-Silicon at higher temperatures is in the order of 103 Ω-cm whereas films grown at lower substrate temperatures show comparatively lower resistivities (~ 102 Ω-cm). From the recorded UV-Visible absorption spectrum the band gap of the film has been estimated to be 3.38 eV.

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Microstructure and Mechanical Behavior of Magnetron Sputtered Al-Cu Films

MRS Proceedings ◽

10.1557/proc-226-203 ◽

1991 ◽

Vol 226 ◽

Cited By ~ 1

Author(s):

Tsann Lin ◽

V. Raman

Keyword(s):

Mechanical Behavior ◽

Grain Morphology ◽

Depth Sensing ◽

Cu Films ◽

Sputtered Films ◽

Fine Grain ◽

Platelet Morphology ◽

Transmission Electron ◽

Indentation Tests ◽

Substrate Temperatures

AbstractWe have investigated the microstructure, electrical resistivity and mechanical behavior of DC magnetron sputtered A1-4wt%Cu films. The substrate temperatures were varied systematically from room temperature to 500 °C. Scanning and transmission electron microscopy of the sputtered films show that the top surface of the films sputtered at low temperatures (< 200 °C) exhibits a pure Al-like fine grain morphology. In contrast, sputter deposition at higher temperatures (> 300 °C) produces films that are characterized at the top surface by a distribution of θ’-A12Cu precipitates with a platelet morphology. The mechanical behavior of the sputtered films were investigated by performing indentation tests using a depth-sensing technique.

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Shape Memory Behavior of Ni-Mn-Ga Sputtered Films under a Magnetic Field

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.44.2513 ◽

2003 ◽

Vol 44 (12) ◽

pp. 2513-2519 ◽

Cited By ~ 12

Author(s):

Makoto Ohtsuka ◽

Masaki Sanada ◽

Minoru Matsumoto ◽

Toshiyuki Takagi ◽

Kimio Itagaki

Keyword(s):

Magnetic Field ◽

Shape Memory ◽

Shape Memory Behavior ◽

Sputtered Films

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Evolution of Stress; Phase Formation and Microstructure in TiCux-Alloy Films

MRS Proceedings ◽

10.1557/proc-580-87 ◽

1999 ◽

Vol 580 ◽

Cited By ~ 1

Author(s):

S. Bertel ◽

R. Abermann

Keyword(s):

Substrate Temperature ◽

Film Growth ◽

Alloy Film ◽

Film Structure ◽

Growth Mode ◽

Alloy Films ◽

Crystalline Films ◽

Influence Of Substrate ◽

20 Nm ◽

Substrate Temperatures

AbstractThe internal stress of TiCux-alloy films on alumina substrates was measured in situ under UHV-conditions as a function of substrate temperature and stoichiometry using a cantilever beam technique.The stress vs. thickness curves of alloy films with TiCu0.5, TiCu, TiCu2 and TiCu3 stoichiometry indicate that the film growth is amorphous at 130°C and polycrystalline at 350°C substrate temperature, which was confirmed by TEM-investigations. Furthermore TED-results of alloys deposited at 350°C imply that the TiCux-alloy-phases formed at that temperature are Ti2Cu, γ-TiCu, TiCu3 and TiCu4.The influence of substrate temperature on the growth of TiCux-alloy films (x = 1) was investigated in more detail. At substrate temperatures below 300°C the stress vs. thickness curves indicate the formation of amorphous alloy films, again confirmed by TEM- and TED-analysis. At substrate temperatures around 300°C a strong tensile stress contribution above a mean thickness of about 20 nm indicates a change in the growth mode and thus microstructure of the alloy film. The corresponding TEM- and TED-micrographs show quasi single-crystalline films. Finally at 350°C substrate temperature the stress vs. thickness curves indicate once again a change in the film growth mode, the film structure is polycrystalline and the formation of γ-TiCu is deduced fore TED-results.

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Shape Memory Behavior of Ti-Ni-X (X= Pd, Cu) Ternary Alloy Thin Films Prepared by Triple-Source DC Magnetron Sputtering

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.2068 ◽

2010 ◽

Vol 638-642 ◽

pp. 2068-2073 ◽

Cited By ~ 2

Author(s):

Shozo Inoue ◽

K. Hori ◽

N. Sawada ◽

N. Nakamoto ◽

T. Namazu

Keyword(s):

Magnetron Sputtering ◽

Shape Memory ◽

Ternary Alloy ◽

Dc Magnetron Sputtering ◽

Recoverable Strain ◽

Alloy Films ◽

Cu Films ◽

Shape Memory Behavior ◽

Cu Content ◽

Transformation Hysteresis

We have deposited the Ti-Ni-X films having various compositions while keeping the Ti content to be ~50at% by means of triple-source dc magnetron sputtering. All of the annealed films showed thermoelastic martensitic transformation. Ms temperature of the Ti-Ni-Pd films increased with increasing Pd content, and the highest Ms temperature of ~180°C was attained for the Ti-23%Ni-27%Pd film. On the other hand, Ms temperature of Ti-Ni-Cu films slightly increases as Cu content increases. The transformation hysteresis is decreased rapidly down to 15~20°C by adding Pd or Cu more than 10at%. Both ternary alloy films showed shape memory behavior during thermal cycling tests under various constant stresses. The critical stress against plastic deformation, c, of the Ti-Ni-Cu films is higher than that of the Ti-Ni-Pd films. The recoverable strain of these ternary alloy films is found to be ~2%. Actuation response by Joule's heat induced shape memory effect of Ti-Ni shape memory alloy films was slightly improved by the addition of Pd or Cu into the alloy.

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