Effect of various sputtering parameters on Ta phase formation using an I-Optimal experimental design

Abstract

Five process factors are varied to find conditions necessary for α and β phase formation in tantalum thin films deposited on SiC. These are: sputtering time, input power, pre-sputter etch time, preheat time at 250 C and sputtering temperature. An empirical model is developed which predicts the maximum or minimum amount of β phase possible over a large range of film thickness (~25 tõ 2,000 nm). The maximum predicted (average) % β phase at the maximum sputtering temperature is only 8%, with 95% confidence bounds of [5%, 12%]. The other factors place a much lower restriction on β phase formation. Pure α phase is easily produced over a wide range of operating conditions. Only a weak relationship is found between film thickness and phase composition. The Ta film resistivity increases with the amount of β phase, in agreement with the literature.

FESEM studies of densely packed aligned nickel nanopillars on silicon substrate by electrochemical deposition through porous alumina membrane

“…Ta is used on Si substrate as the metallic contact layer during Ni electrodeposition because of the several interesting properties of Ta, such as, it is an refractory metal which is considered to be an attractive coating material in many applications for its good adhesivity with uniform coating properties, high toughness, ductility, low electrical resistivity and corrosion resistance [20][21][22]. Also Ta has been used as a diffusion barrier between Al and Si as the reaction temperatures of Al/Ta and Ta/Si were reported to be relatively high [23,24].…”

The structure of small Ta clusters

“…The structural evolution of Ta clusters of fewer than ∼100 atoms and formation of β-phase for large clusters (N > ∼100) provide insights into the β-phase formation in depositing Ta thin film. Substrate temperature was found to be one of the most important factors in controlling the crystal structure of the deposited Ta film [55][56][57][58]. The high substrate temperatures promote the formation of bcc Ta over the β-phase.…”

“…Similarly in our MD simulations, the rapid cooling does not provide atoms with enough time to rearrange themselves and locate the lowest-energy positions. Substrate temperatures reported to produce a completely bcc phase coating using an argon sputtering gas have typically been greater than 300 • C and as high as 600 • C [57][58][59][60].…”

Large field enhancement at electrochemically grown quasi-1D Ni nanostructures with low-threshold cold-field electron emission

“…Ta is a refractory metal with attractive coating properties such as good adhesivity, high toughness, ductility, low electrical resistivity, corrosion resistance, etc [29]. Also Ta has been used as a diffusion barrier between Al and Si, as the reaction temperatures of Al/Ta and Ta/Si were reported to be relatively high [30].…”