NiTi shape memory alloy thin films: composition control using optical emission spectroscopy

Bendahan, Marc; Seguin, Jean-Luc; Canet, P.; Carchano, H.

doi:10.1016/0040-6090(95)08254-9

Cited by 34 publications

(18 citation statements)

References 17 publications

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“…As the Ar gas pressure increases, the Ti concentration increases. This result qualitatively agrees with that reported by Bendahn et al 9) for an alloy target. The pressure dependence of the composition of sputtered films is often discussed in relation to the probability of sputtered atoms arriving at the substrate.…”

Section: Methodssupporting

confidence: 93%

Composition Control of NiTi Shape Memory Alloy Films Formed by Sputter Deposition with a Composite Target

Takeda¹,

Yamazaki

Nakajima³

2000

Jpn. J. Appl. Phys.

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In order to obtain NiTi films by magnetron sputtering, the authors devised a target composed of Ti and Ni rings and a Ti disk. The fabricated films were analyzed by energy-dispersive X-ray analysis (EDX) and Rutherford backscattering spectrometry (RBS). X-ray diffraction measurements (XRD) of the films were also carried out. It was shown that the composition of the film formed with the target was easily controlled with an accuracy of 0.5 at.% by changing the electric current flowing through the solenoid coil of an electromagnet. The composition of the film was affected by the Ar gas pressure. It was also shown that a film with an in-depth composition gradient was easily formed. The obtained films were confirmed by a bending test to show the shape memory effect.

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Section: Methodssupporting

confidence: 93%

Composition Control of NiTi Shape Memory Alloy Films Formed by Sputter Deposition with a Composite Target

Takeda¹,

Yamazaki

Nakajima³

2000

Jpn. J. Appl. Phys.

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“…Introduction TiNi shape memory thin films are materials with a high potential for fabricating the microactuators and micropumps used in microelectromechanical systems because of the advantages of their large shape recovery force and strain. Hence, efforts have been made with TiNi thin films using rf sputtering techniques (Wolf and Heuer 1995, Bendahan et al 1996, Stemmer et al 1997, Miyazaki and Ishida 1999, Chen and Wu 1999, Matsunaga et al 2000, Wu et al 2001. Because the TiNi thin films are amorphous when initially deposited on to low-temperature substrates, thermal annealing is necessary for the crystallization of these films (Stemmer et al 1997, Chen and Wu 1999, Wu et al 2001.…”

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confidence: 99%

Interfacial reactions of rf-sputtered TiNi thin films on (100) silicon with a SiN diffusion barrier

Wang

2004

Philosophical Magazine

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Silicon nitride (SiN) with a 50 nm thickness on Si(100) as a thermal barrier was obtained by plasma-enhanced chemical vapour deposition (PECVD). TiNi thin films were rf sputtered on a SiN/Si substrate and then annealed at 400-700 C for 30 min. Their interfacial reactions were studied using transmission electron microscopy, X-ray diffraction and Auger electron spectroscopy analyses. Experimental results show that the thickness of reaction layer in TiNi/SiN/Si specimens is clearly reduced, compared with that in TiNi/Si specimens under the same annealing conditions. The significant effect of the SiN layer as a diffusion barrier in TiNi/SiN/Si can be recognized. N and Si atoms diffuse from the SiN layer to react with TiNi films at 500 C and 600 C respectively. The TiN 1 À x phase is formed in specimens annealed at 500 C, and mixed Ti 2 Ni 3 Si and Ti 4 Ni 2 O compounds are found at 600 C. In the specimen annealed at 700 C, the reaction layer has sublayers in the sequence TiNi/Ti 4 Ni 2 O/Ti 2 Ni 3 Si/TiN 1 À x / SiN/Si. The SiN thermal barrier obtained by PECVD caused quite different diffusion species to cross the interfaces between TiNi/SiN/Si and TiNi/Si specimens during the annealing.

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“…The initial energy of ejecting atoms from the target depends mainly on their mass [13]. The energy loss is related to the transport process from target to substrate.…”

Section: Effect Of Ar Gas Pressurementioning

confidence: 99%

Some factors affecting the properties of sputter deposited NiTi-based shape memory alloy thin films

Huang

Liu

2002

SPIE Proceedings

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Several factors affecting the surface morphology, transformation characteristics and shape recovery of co-sputtered NiTi-based shape memory alloy thin films were investigated. It is found that the Ar gas pressure, substrate orientation, deposition temperature and annealing condition all affect the surface morphology. In particular, when under high Argon gas pressure, the deposited film contains surface cracks, while the film is smooth and dense if a 2.3mTorr Argon gas pressure was used during deposition. The film deposited at 450 o C on a (100) Si substrate has a rough surface associated with a large distribution of island sizes. Post-annealing treatment leads to a more homogeneous distribution of island dimensions and a smoother surface. On the other hand, the films deposited at 450 o C on a (111) Si substrate or on a SiO 2 buffer layer have more homogeneous island sizes. It is also found that both the substrate orientation and the SiO 2 buffer layer dramatically affect the transformation behavior and shape recovery magnitude. Film deposited on (100) Si has a higher recovery strain than that deposited on (111) Si under the same stress. The oxygen in SiO 2 buffer layer may have deteriorated the deposited film, which results in a very low shape recovery strain. Interfacial stress between the substrate and the thin films is found to lower the transformation hysteresis.

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NiTi shape memory alloy thin films: composition control using optical emission spectroscopy

Cited by 34 publications

References 17 publications

Composition Control of NiTi Shape Memory Alloy Films Formed by Sputter Deposition with a Composite Target

Composition Control of NiTi Shape Memory Alloy Films Formed by Sputter Deposition with a Composite Target

Interfacial reactions of rf-sputtered TiNi thin films on (100) silicon with a SiN diffusion barrier

Some factors affecting the properties of sputter deposited NiTi-based shape memory alloy thin films

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