Structure and stability of sputter deposited beta-tungsten thin films

Weerasekera, I.; Shah, S. Ismat; Baxter, David V.; Unruh, Karl

doi:10.1063/1.111318

Cited by 116 publications

(75 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the growth progressed to a larger thickness the α-phase for the NISD grew faster and the β-phase was suppressed. This behavior is consistent with that reported in the literature [7,9]. On the other hand, for the OASD we observed an opposite behavior.…”

Section: Introductionsupporting

confidence: 82%

“…Depending on the growth conditions and thickness of the films, normal incidence sputter deposition (NISD) of tungsten films can give rise to either the α-phase W, which has the equilibrium bcc structure, or the metastable β-phase W, which has an A15 (cubic) structure, or a mixture of both phases [6,7]. The lattice constants are 3.16 o A and 5.04 o A for α-W and β-W, respectively.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Growth of Single Crystal Tungsten Nanorods by Oblique Angle Sputter Deposition

Karabacak

Wang

et al. 2003

MRS Proc.

View full text Add to dashboard Cite

We report the creation of single crystal tungsten nanorods with unusual simple cubic β-phase. These novel nano-structures were grown by oblique angle sputter deposition with substrate rotation through a shadowing effect. Transmission electron microscopy (TEM) diffraction patterns from individual nanorods clearly show the single crystal structure. It is evident from TEM diffraction measurements, during the oblique angle deposition, both β-phase W(100) and α-phase W(110) islands exist at the initial stages of growth. However, at later stages of the growth the β-phase structure dominates. This is in contrast to the sputter deposition at normal incidence where only the thermodynamically stable bcc α-phase W(110) polycrystalline films were formed when the film grew to a certain thickness. We explain our results by using the shadowing and adatom mobility mechanisms: At the initial stages of growth, the β-phase W(100) islands grow taller due to the lower adatom mobility on these islands. The taller β-phase W(100) islands survive in the competition during oblique angle growth and form isolated nanorods in the later stages, while the shorter α-phase W(110) islands stop growing due to the shadowing effect. In addition, our Monte Carlo simulation results agree well with the experimental measurements.

show abstract

Section: Introductionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Growth of Single Crystal Tungsten Nanorods by Oblique Angle Sputter Deposition

Karabacak

Wang

et al. 2003

MRS Proc.

View full text Add to dashboard Cite

show abstract

“…Thermally induced structural transformation to the stable bcc phase has also been observed with metastable phases of tungsten. 4 There have however been conflicting reports regarding the oxygen content of bcc tungsten formed by heating relative to its metastable precursor, 4,6 which is known to be about three times more resistive than bcc tungsten. 20,21 In order to determine whether the bct phase of Ta …”

Section: Superconductive Tunneling Experiments On Nb Single Crystals mentioning

confidence: 99%

“…Several authors 4,6,20 have reported a metastable form of tungsten with a lattice constant of approximately 0.504 nm, which crystallizes in the A-15 structure and is referred to as β tungsten. The A-15 β-W cubic A-2 α-W upon heating, although the reported transition temperature ranges vary widely.…”

Section: A Metastable Phase Of Tungstenmentioning

confidence: 99%

See 1 more Smart Citation

Theory of the structural phases of group 5B–6B metals and their transport properties

Nnolim

Tyson

Axe

2003

Journal of Applied Physics

View full text Add to dashboard Cite

In order to predict the stable and metastable phases of the bcc metals in the block of the Periodic Table defined by groups 5B to 6B and periods 4 to 6, as well as the structure dependence of their transport properties, we have performed full potential computations of the total energies per unit cell as a function of the a c ratio at constant experimental volume. In all cases, a metastable body centered tetragonal (bct) phase was predicted from the calculations. The total energy differences between the calculated stable and metastable phases ranged from 0.09 eV/cell (vanadium) to 0.39 eV/cell (tungsten). The trends in resistivity as a function of structure and atomic number are discussed in terms of a model of electron transport in metals. Theoretical calculations of 2 the electrical resistivity and other transport properties show that bct phases derived fromgroup 5B elements are more conductive than the corresponding bcc phases, while bct phases formed from group 6B elements are less conductive than the corresponding bcc phases. Special attention is paid to the phases of tantalum where we show that the frequently observed β phase is not a simple tetragonal distortion of bcc tantalum.

show abstract

Phase‐Control Enabled Superior Mechanical and Electrical Properties of Nanocrystalline Tungsten‐Molybdenum Thin Films

Martínez

Ramana

2017

Adv Eng Mater

View full text Add to dashboard Cite

The authors report on the design and stabilization of the mechanically hard and electrically resistive b-phase W-Mo nanocrystalline thin films at room-temperature (RT). The W-Mo films are deposited under different deposition temperatures in the range of T s ¼ RT-30 C. Structural analyses indicate that, as deposited at RT, the W-Mo films crystallize in the metastable b-phase, while those deposited at higher T s (100-300 C) exhibit the thermodynamically stable a-phase. The phase-effect is significant on the mechanical characteristics; superior hardness (H); and modulus of elasticity (E r ) are found in b-than in aphase W-Mo films. At the b-to-a phase transformation, significant reduction occurs in H (40 ! 25 GPa) and E r (275 ! 225 GPa) coupled with a reduction in electrical-resistivity (320 ! 180 mV-cm). Their findings and the phase-mechanical-electrical property correlation established may provide further possibilities to design and tailor the performance of W-based thin films for future electronic and electromechanical device applications.

show abstract

Structure and stability of sputter deposited beta-tungsten thin films

Cited by 116 publications

References 13 publications

Growth of Single Crystal Tungsten Nanorods by Oblique Angle Sputter Deposition

Growth of Single Crystal Tungsten Nanorods by Oblique Angle Sputter Deposition

Theory of the structural phases of group 5B–6B metals and their transport properties

Phase‐Control Enabled Superior Mechanical and Electrical Properties of Nanocrystalline Tungsten‐Molybdenum Thin Films

Contact Info

Product

Resources

About