High Hf Content NITIHF Shape Memory Films

AbstractPolycrystalline NiTiHf films with around 9at% Hf have been successfully deposited from a single NiTiHf target using a DC magnetron sputtering system. Free standing films were obtained by depositing the films on single crystal silicon substrates. Thickness of the films was controlled between 10-12µm. In this investigation, the effects of deposition temperature on the crystallinity and transformation temperatures of the films were studied. Substrate temperature during deposition was varied between 300°C and 700°C at 100°C intervals. The influence of heat treatment temperature on the properties of the films was also investigated. The heat treatment temperature was between 300°C and 800°C at 100° C intervals. Transformation temperatures of these films were determined by differential scanning calorimetry (DSC). The crystallinity was determined using x-ray diffractometry. It was found that all the as-deposited films were crystalline even when the substrate temperature was as low as 300°C. Both martensite and austenite transformation temperatures increase with increasing substrate temperature and increasing heat treatment temperature.

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Laser Writing of High Purity Gold Lines

MRS Proceedings ◽

10.1557/proc-158-129 ◽

1989 ◽

Vol 158 ◽

Cited By ~ 2

Author(s):

M. Jubber ◽

J.I.B. Wilson ◽

J.L. Davidson ◽

P. John ◽

P.G. Roberts

Keyword(s):

Rectangular Cross Section ◽

Single Crystal Silicon ◽

Gold Surface ◽

Decomposition Temperature ◽

Silicon Substrates ◽

Beam Diameter ◽

Scanning Calorimetry ◽

Crystal Silicon ◽

Ion Laser ◽

Stage Process

ABSTRACTGold tracks have been deposited on thermally oxidised and single crystal silicon, gold and nichrome coated silicon wafers by pyrolytic decomposition of gaseous alkyl (triethyl phosphine) gold(I) complexes using focussed 514 nm radiation from an argon ion laser. The precursors, RAu(I)Et3P, R = CH3, C2H5 are low melting point crystalline solids with relatively high vapour pressures (∼5 mtorr). They are representative of a class of compounds being evaluated for laser deposition of gold. Differential scanning calorimetry, DSC, shows that the thermal decomposition of MeAu(I)Et3P in the solid state is a two-stage process. The decomposition temperature is 63 ± 1°C. Tracks were deposited at laser scan speeds up to 35 μm s−1 with a beam diameter (1/e2) at the focus of ∼12 μm. SIMS, EDX and laser ionisation microprobe analysis, LIMA, were used to determine the chemical composition of the tracks. The purity of >98% is consistent with the measured resistivities (4.2 μΩ cm) at room temperature compared to bulk gold (∼2 μΩ cm). These resistivities were achieved without post deposition annealing. Stylus profilimetry and SEM data showed the lines produced from MeAu(I)Et3P have a virtually rectangular cross-section. Together with the absence of the ubiquitous λ-ripples, this feature suggests that deposition is more rapid on the gold surface than on the SiO2 substrate. Laser power thresholds are lower for silicon substrates coated with thin (5 - 10°A) films of gold or nichrome.

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Shallow Contact Formation of Gadolinium Silicide

MRS Proceedings ◽

10.1557/proc-25-39 ◽

1983 ◽

Vol 25 ◽

Cited By ~ 1

Author(s):

I. C. Cheng ◽

S. S. Lau ◽

R. D. Thompson ◽

K. N. Tu

Keyword(s):

Heat Treatment ◽

Single Crystal ◽

Schottky Barrier Height ◽

Single Crystal Silicon ◽

Atomic Ratio ◽

Silicon Substrates ◽

Formation Temperature ◽

Crystal Silicon ◽

Contact Formation ◽

Convenient Technique

ABSTRACTGadolinium silicide with its attractive features of low formation temperature of about 350°C and low Schottky barrier height on n-type single-crystal silicon substrates (ϕnB1∼O.4ev,ϕpB ∼ 0.7ev) was chosen for studying the feasibility of forming shallow uniform contacts. Samples with various compositions prepared by both bilayer evaporation with a configuration of Si(α)/Gd/Si(xtl) and coevaporation with a Si−Gd /Si(xtl)structure were used for studying the contact formation as a function of composition and heat treatment. We found that shallow contact formation can be achieved provided that the following conditions are met: (a) for bilayer evaporation, the atomic ratio of Si(α)/Gd ≥ 2 should be maintained, (b) for coevaporation, the Si to Gd atomic ratio between 1.7 and 2.0 is desired. The bilayer deposition scheme appears to be a more convenient technique to use in practice.

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Transformation Behavior of TiNiPt Thin Films Fabricated Using Melt Spinning Technique

MRS Proceedings ◽

10.1557/proc-842-s3.2 ◽

2004 ◽

Vol 842 ◽

Cited By ~ 6

Author(s):

Tomonari Inamura ◽

Yohei Takahashi ◽

Hideki Hosoda ◽

Kenji Wakashima ◽

Takeshi Nagase ◽

...

Keyword(s):

Heat Treatment ◽

Martensitic Transformation ◽

Heat Treatment Temperature ◽

Melt Spinning ◽

Bulk Material ◽

Parent Phase ◽

Treatment Temperature ◽

Transformation Behavior ◽

Scanning Calorimetry ◽

Similar Chemical

ABSTRACTMartensitic transformation behavior of Ti50Ni40Pt10 (TiNiPt) melt-spun ribbons were investigated where the heat treatment temperature was systematically changed from 473K to 773K. A hot-forged bulk TiNiPt material with the similar chemical composition was also tested as a comparison. θ-2θ X-ray diffraction analysis and transmission electron microscopy observation revealed that the as-spun ribbons were fully crystallized. The apparent phases of as-spun ribbons at room temperature are both B19 martensite and B2 parent phase instead of B2 single phase for the hot-forged bulk material. No precipitates were found in as-spun and heat-treated ribbons. It was revealed by differential scanning calorimetry that all the specimens exhibit one-step transformation. The martensitic transformation temperatures of the TiNiPt as-spun ribbons are 100K higher than those of the hot-forged bulk material, and the martensitic transformation temperature decreases with increasing heat treatment temperature.

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An Epitaxial Si/insulator/Si Structure Prepared by Vacuum Deposition of CaF2 and Silicon

MRS Proceedings ◽

10.1557/proc-10-145 ◽

1981 ◽

Vol 10 ◽

Author(s):

T. Asano ◽

H. Ishiwara

Keyword(s):

Substrate Temperature ◽

Silicon Film ◽

Single Crystal Silicon ◽

Rutherford Backscattering ◽

Film Deposition ◽

Silicon Substrates ◽

Optimum Conditions ◽

Crystal Silicon ◽

Transmission Electron ◽

Substrate Temperatures

Heteroepitaxial CaF2/Si and Si/CaF2/Si structures were prepared by conventional vacuum evaporation of CaF2 and silicon onto silicon substrates. The optimum conditions for obtaining good epitaxial films were investigated by changing the silicon substrate orientation, the film thickness and the substrate temperature during film deposition. From Rutherford backscattering and channelling spectroscopy it was found that CaF2 films with excellent film quality were obtained on Si(111), Si(110) and Si(100) substrates at substrate temperatures of 600– 800°C, 800°C and 500–600°C respectively. It was also found from Rutherford backscattering and channelling spectroscopy and from transmission electron microscopy that single-crystal silicon films are formed on a CaF2/Si(111) structure at a substrate temperature of 700°C. From measurements of the electrical properties of the top silicon film after the implantation of phosphorus ions at 2 ×1015 cm−2 and subsequent annealing at 750°C, an electron Hall mobility of 69cm2 V−1 s−1 was obtained.

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Temperature Effects on Internal Stress in Molybdenum Thin Films on Single-Crystal Silicon Substrates

MRS Proceedings ◽

10.1557/proc-18-251 ◽

1982 ◽

Vol 18 ◽

Author(s):

Jiann-Ruey Chen ◽

Ching-Hung Ho

Keyword(s):

Thin Films ◽

Substrate Temperature ◽

Annealing Temperature ◽

Rutherford Backscattering Spectrometry ◽

Single Crystal Silicon ◽

Internal Stresses ◽

Silicon Substrates ◽

Crystal Silicon ◽

Lower Annealing Temperature ◽

Spectrometry Technique

Molybdenum thin films were deposited with an electron beam gun onto (100)- oriented silicon substrates. The samples were then annealed in vacuum, and the internal stresses in the molybdenum thin films were studied as functions both of the annealing temperature and of the substrate temperature during deposition. Silicide formation and the film thickness after annealing were monitored by the Rutherford backscattering spectrometry technique, and the stress was determined from the substrate curvature which was measured from Newton's ring interference fringes. It was found that, when the substrate temperature was kept at 400°C during deposition, MoSi2 was formed after annealing at temperatures above 500 °C. This MoSi2 exhibited large tensile stresses of about 2 × 1010 dyn cm−2 for annealing above 700 °C, whereas at the lower annealing temperature of 500 °C the stresses were compressive. No detectable silicides were observed when the substrates were kept at temperatures below 150 °C. The Mo-Si film stresses were tensile for substrates kept at room temperature during deposition and compressive for substrates kept at 150 °C.

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Surface Evolution of NiTi and NiTiHf Thin Films

MRS Proceedings ◽

10.1557/proc-648-p6.38 ◽

2000 ◽

Vol 648 ◽

Author(s):

Chen Zhang ◽

Ralph H. Zee ◽

Paul E. Thoma

Keyword(s):

Thin Films ◽

Grain Size ◽

Substrate Temperature ◽

Deposition Temperature ◽

Single Crystal Silicon ◽

Free Standing ◽

Crystal Silicon ◽

Cross Sectional ◽

Surface Evolution ◽

Post Deposition

AbstractThe microstructure evolution of Ti-rich NiTi thin films and (TiHf)-rich NiTiHf thin films containing 9at% Hf was investigated. These films were deposited from single NiTi and NiTiHf targets using a DC magnetron sputtering system. Free-standing films were obtained by using single crystal silicon substrates. The thickness of these films was controlled between 10-12 μm. In this investigation, the effects of deposition temperature on the surface and cross-sectional microstructures of these films were studied. Substrate temperature during deposition was varied between 300°C to 700°C at 100°C intervals. The influence of post deposition heat treatment (HT) temperature on the microstructure of these films was also studied. The post deposition HT temperature was varied between 300°C and 800°C at 100°C intervals. Both surface and cross- sectional microstructures were examined using a scanning electron microscope (SEM). The crystallinity and the phases present were determined using x-ray diffractometry. All the as- deposited films were found to be crystalline, even when the substrate temperature was as low as 300°C. Results from the microstructure analysis show that all the films have a relatively fine grain size ranging from 0.2 μm to 2.5 μm, and the grain size increases with increasing substrate deposition temperature. The effect of post deposition HT on grain size was found to be minimal.

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Characterization of NiTi Shape Memory Wires by Differential Scanning Calorimetry and Transmission X-ray Diffraction

MRS Proceedings ◽

10.1557/proc-246-225 ◽

1991 ◽

Vol 246 ◽

Author(s):

Ming-Yuan Kao ◽

Sepehr Fariabi ◽

Paul E. Thoma ◽

Husnu Ozkan ◽

Louis Cartz

Keyword(s):

Heat Treatment ◽

Differential Scanning Calorimetry ◽

Heat Treatment Temperature ◽

Room Temperature ◽

Cold Work ◽

Treatment Temperature ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Niti Wires

AbstractThe reversible transformations between the Austenite (A) and Martensite (M) phases of NITI shape memory wires having a 78°C austenlte finish temperature (950°C annealed) were studied In the cold work and heat treatment ranges between 14 to 62% and 400 to 525°C respectively. The ranges of peak Transformation Temperatures (TI), determined by Differential Scanning Calorimetry (DSC) at a 10°C/min rate, were found to be 56 to 75°C, -28 to 33°C, and 38 to 52°C for the respective high temperature A, low temperature M, and the Intermediate Rhombohedral (R) phases. The degree of cold work and heat treatment had significant effects on the TT of NITI wires. The peak TT of A and M decreases with Increasing cold work. Except for the 14% cold worked wires, the peak TT Increases with Increasing heat treatment temperature for M, and Increases with Increasing heat treatment temperature for A for temperatures higher than 450°C. The peak IT of R Increases with Increasing cold work and decreasing heat treat temperature.Using MoKα radiation, transmission x-ray diffraction analysis was utilized to determine the phases at room temperature on wires thinned down to 0.05 to 0.01 mm in diameter. The diffraction patterns of body-centered cubic austenite (132) and monodlinic martenslte (B19) for NITi were both Identified. In addition, extra diffraction lines observed for various samples were tentatively assigned to M and the Intermediate R-phase. Depending on the thermal history and the processing conditions, the NITI wires consist of either a pure M, a mixture of A and R, or a mixture of A, R, and M at room temperature.

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TEM characterization of Au/Polysilicon interactions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176381 ◽

1990 ◽

Vol 48 (4) ◽

pp. 650-651

Author(s):

N. David Theodore ◽

Leslie H. Allen ◽

C. Barry Carter ◽

James W. Mayer

Keyword(s):

Solid Phase ◽

Single Crystal Silicon ◽

Chemical Vapor ◽

Electrical Contacts ◽

Silicon Substrates ◽

Crystal Silicon ◽

Transmission Electron ◽

Polysilicon Films ◽

The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

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