The structure and stability of β-Ta thin films

Abstract

Ta films with tetragonal crystalline structure (h-phase), deposited by magnetron sputtering on different substrates (steel, silicon, and silicon dioxide), have been studied. In all cases, very highly preferred (001) orientation was observed in X-ray diffraction measurements. All diffraction data revealed two weak reflections corresponding to d-spacing of 0.5272 and 0.1777 nm. The presence of the two peaks, attributed to (001) and (003) reflections, indicates that h-Ta films exhibit a high preference for the space group of P-42 1 m over P4 2 /mnm, previously proposed for h-Ta. Differences in relative intensities of (00l) reflections, calculated for single crystal h-Ta j-type Frank-Kasper structure and those measured in the films, are attributed to defects in the films. Molecular dynamics simulations performed on tantalum clusters with six different initial configurations using the embedded-atom-method potential revealed the stability of h-Ta, which might explain its growth on many substrates under various deposition conditions. D

Effect of Ta buffer layer and thickness on the structural and magnetic properties of Co thin films

“…It is well known that Ta has two structural phases: bcc cubic and ␤-Ta. 12 The full width at half maximum of the Ta peak is 0.398°and the corresponding grain size is 21 nm. The thickness of the Ta does not affect the structural quality of the 25 nm Co layer significantly.…”

Effect of Ta buffer layer and TaO x barrier thickness on the evolution of the structural and magnetic properties of the Fe/TaO x /Co trilayers

“…A Ta film shows a strong texture in the (200) direction. It is well known that Ta has two structural phases, bcc cubic and β-Ta [19,20]. The FWHM of this peak is 0.55 • and the calculated grain size is 14.9 nm.…”

Effects of Cu Self-Capping and Ta Capping on Nanometer-Sized Cu Films Sputter-Deposited on β-Ta

“…5(a) denotes a d Ta002 of 268.65 pm in the 35-nm-thick Ta barrier alone. For the bulk value, a d Ta002 of 266.4 pm was reported for a 30-mm-thick -Ta film deposited on an AISI4340 steel substrate, 21) whereas a value of 265.32 pm was reported for a $20-mm -Ta single crystal.…”

“…12,[18][19][20][21][22] In our previous work, the Ta barrier layers deposited on Si reed substrates with undulated surfaces consisted of an equilibrium -Ta phase and -Ta phase. 4) In contrast, the Ta barrier layers deposited on Si reed substrates with a mirror surface consisted solely of the -Ta phase.…”