Comparative Studies of PST Thin Films as Prepared by Sol-Gel, LDCVD and Sputtering Techniques

Huang, Zhaorong; Donohue, Paul P.; Zhang, Qi; Williams, D.; Anthony, Carl; Todd, M. A.; Whatmore, R. W.

doi:10.1080/10584580215349

Cited by 8 publications

(12 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…TaN is one of the best diffusion barrier materials between silicon and copper. − SrBi 2 Ta 2 O 9 is a ferroelectric material that has been extensively investigated for nonvolatile ferroelectric memory applications . Pb(Sc 0.5 Ta 0.5 )O 3 exhibits pyroelectric and ferroelectric properties . The ongoing miniaturization of features in microelectronics devices requires the growth of these materials as thin, conformal films.…”

Section: Introductionmentioning

confidence: 99%

Volatility and High Thermal Stability in Tantalum Complexes Containing Imido, Amidinate, and Halide or Dialkylamide Ligands

Wiedmann¹,

Heeg²,

Winter³

2009

Inorg. Chem.

View full text Add to dashboard Cite

Treatment of Ta(NtBu)Cl(3)(py)(2) with 2 equiv of Li(iPrNCMeNiPr) or Li(tBuNCMeNtBu) afforded Ta(NtBu)(iPrNCMeNiPr)(2)Cl and Ta(NtBu)(tBuNCMeNtBu)(2)Cl in 63% and 61% yields, respectively. Treatment of Ta(NtBu)(iPrNCMeNiPr)(2)Cl or Ta(NtBu)(tBuNCMeNtBu)(2)Cl with LiNRR' afforded Ta(NtBu)(iPrNCMeNiPr)(2)(NRR') and Ta(NtBu)(tBuNCMeNtBu)(2)(NRR') in 79-92% yields (R, R' = Me, Et). Treatment of Ta(NtBu)(tBuNCMeNtBu)(2)Cl with AgBF(4) afforded Ta(NtBu)(tBuNCMeNtBu)(2)F in 54% yield, while treatment of Ta(NtBu)(tBuNCMeNtBu)(2)Cl with BBr(3) afforded Ta(NtBu)(tBuNCMe-NtBu)(2)Br in 68% yield. X-ray crystal structures of Ta(NtBu)(tBuNCMeNtBu)(2)F and Ta(NtBu)(tBuNCMeNtBu)(2)Br revealed that the amidinate ligands exhibit eta(2)-coordination, and that the imido and halide ligands are cis to each other within the distorted octahedral structures. NMR studies indicated that the other complexes have analogous structures. Additionally, variable temperature NMR studies revealed that some of the complexes undergo amidinate rearrangement. The enthalpies, entropies, and free energies of activation for these rearrangements were calculated for Ta(NtBu)(tBuNCMeNtBu)(2)X (X = F, Cl, Br). When X = F, DeltaH(double dagger) = 9.1 +/- 0.4 kcal/mol, DeltaS(double dagger) = -20.5 +/- 1.6 cal/mol x K, and DeltaG(double dagger)(298 K) = 15.3 +/- 0.7 kcal/mol. For X = Cl, DeltaH(double dagger) = 12.4 +/- 0.3 kcal/mol, DeltaS(double dagger) = -20.2 +/- 0.8 cal/mol x K, and DeltaG(double dagger)(298 K) = 18.4 +/- 0.3 kcal/mol. When X = Br, DeltaH(double dagger) = 12.5 +/- 0.5 kcal/mol, DeltaS(double dagger) = -21.7 +/- 1.5 cal/mol x K, and DeltaG(double dagger)(298 K) = 19.0 +/- 0.7 kcal/mol. All of the complexes are volatile, and they sublime between 120 and 203 degrees C. In addition, Ta(NtBu)(iPrNCMeNiPr)(2)NMe(2) has a decomposition point that is 65-160 degrees C higher than widely used film growth precursors and is therefore a promising candidate for use in chemical vapor deposition and atomic layer deposition film growth techniques.

show abstract

Section: Introductionmentioning

confidence: 99%

Volatility and High Thermal Stability in Tantalum Complexes Containing Imido, Amidinate, and Halide or Dialkylamide Ligands

Wiedmann¹,

Heeg²,

Winter³

2009

Inorg. Chem.

View full text Add to dashboard Cite

show abstract

“…The film shows the presence of voids, concentrated especially at the grain boundary. However, the concentration of voids is significantly less than that reported in sputtered PST, 8 and their position at the grain boundary lessens their impact on the dielectric response measured "out-of-plane," where the grain boundary contribution to the capacitance is parallel with the "bulk" film response. Void formation is often observed in the PST system and has been recently attributed to the formation of the intermediate pyrochlore phase, which forms before arriving at the final perovskite phase.…”

Section: Film Fabrication Excess Leadmentioning

confidence: 79%

“…It has been demonstrated in ceramics 23 and single crystals 24 that ordered PST behaves as a conventional ferroelectric, whereas disordered PST exhibits relaxor ferroelectric behavior. Relaxor behavior in PST thin films was typically observed after low processing temperatures near 700°C, [7][8][9]25 whereas ceramic sintering conditions for disordered PST were significantly higher near 1500°C. 26,27 In the majority of studies of PST for infrared detectors operating in the bolometer mode, a significant degree of ordering is sought because this increases the sharpness of the phase transition and enhances the DC bias induced pyroelectric properties.…”

Section: Introductionmentioning

confidence: 99%

“…ScTaO 4 and PbO were sputter deposited in alternating layers and subsequently reacted by high temperature annealing above 900°C to promote diffusion and obtain the desired perovskite phase. 28 PST has been successfully prepared by sputtering, 29 pulsed laser deposition, 30 and CVD, 8 in addition to chemical solution deposition methods. The most recent work focuses on films sputtered at low temperatures near 300°C, followed by post annealing at intermediate temperatures near 500°C.…”

Section: Introductionmentioning

confidence: 99%

“…1 However, consistent experimental investigations by the ferroelectric community have confirmed the lowdielectric constant of relaxor thin films in a wide variety of materials such as lead magnesium niobate (PMN), 2,3 lead magnesium niobate-lead titanate (PMN-PT), 4 lead scandium niobate (PSN), 5,6 and lead scandium tantalate (PST). [7][8][9] Thin film relaxor PST 10 and PMN 11 were recently shown to possess similar lattice dynamics compared with their bulk counterparts. The appearance of polar nanoregions as observed by Fourier transform infrared (FTIR) studies confirmed that the defining feature of relaxor structure, namely the existence of polar nanoregions is qualitatively similar in bulk and thin films.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Processing and properties of ferroelectric relaxor lead scandium tantalate Pb(Sc_1/2Ta_1/2)O₃ thin films

et al. 2007

View full text Add to dashboard Cite

Thin films of Pb(Sc 1/2 Ta 1/2 )O 3 (PST) were fabricated using an optimized chemical solution deposition procedure involving the de-hydration of scandium acetate and the addition of up to 30% excess lead in solution. The choice of substrate was found to impact the thermal induced stress in the films as confirmed by wafer bending and in-plane grazing angle x-ray diffraction measurements. The presence of either a compressive or a tensile in-plane stress led to a reduction in the temperature of the dielectric maximum, whereas the value of the dielectric maximum remained relatively unchanged; its value reduced by an order of magnitude compared with ceramic samples. It is concluded that mechanical stress alone is not the sole factor in the reduction of PST thin film permittivity. Microstructural features resulting from processing induced defects or an incomplete transformation to the relaxor state may be responsible for this commonly observed phenomenon.

show abstract

Growth of Tantalum(V) Oxide Films by Atomic Layer Deposition Using the Highly Thermally Stable Precursor Ta(NtBu)(iPrNC(Me)NiPr)₂(NMe₂)

Wiedmann

Karunarathne

Baird³

et al. 2010

Chem. Mater.

View full text Add to dashboard Cite

The atomic layer deposition (ALD) growth of Ta 2 O 5 films was demonstrated using Ta(NtBu)-(iPrNC(Me)NiPr) 2 (NMe 2 ) and water with substrate temperatures between 225 and 400 °C. At 325 °C, self-limited growth was demonstrated with Ta(NtBu)(iPrNC(Me)NiPr) 2 (NMe 2 ) and water pulse lengths of g0.5 s. An ALD window was observed between 275 and 350 °C, with a growth rate of 0.28 A ˚/cycle. The growth rates were 0.33 and 0.37 A ˚/cycle at 250 and 225 °C, respectively. At 375 and 400 °C the growth rate increased slightly to 0.31 A ˚/cycle, and precursor thermal decomposition may contribute to growth at these temperatures. In a series of films deposited at 325 °C, the film thickness increased linearly with the number of deposition cycles. X-ray photoelectron spectroscopy of films deposited at 300 and 350 °C revealed stoichiometric Ta 2 O 5 with carbon and nitrogen levels below the detection limits. The films were amorphous as deposited, but annealing at 700 °C in dry air resulted in crystallization of hexagonal δ-Ta 2 O 5 . Atomic force microscopy found root-mean-square surface roughnesses of 0.6-0.7 nm for 45 nm thick films deposited at 300 and 350 °C. The index of refraction of films grown at 325 °C was determined to be 2.12-2.16 at 633 nm using ellipsometry.

show abstract

Comparative Studies of PST Thin Films as Prepared by Sol-Gel, LDCVD and Sputtering Techniques

Cited by 8 publications

References 3 publications

Volatility and High Thermal Stability in Tantalum Complexes Containing Imido, Amidinate, and Halide or Dialkylamide Ligands

Volatility and High Thermal Stability in Tantalum Complexes Containing Imido, Amidinate, and Halide or Dialkylamide Ligands

Processing and properties of ferroelectric relaxor lead scandium tantalate Pb(Sc_1/2Ta_1/2)O₃ thin films

Growth of Tantalum(V) Oxide Films by Atomic Layer Deposition Using the Highly Thermally Stable Precursor Ta(NtBu)(iPrNC(Me)NiPr)₂(NMe₂)

Contact Info

Product

Resources

About

Comparative Studies of PST Thin Films as Prepared by Sol-Gel, LDCVD and Sputtering Techniques

Cited by 8 publications

References 3 publications

Volatility and High Thermal Stability in Tantalum Complexes Containing Imido, Amidinate, and Halide or Dialkylamide Ligands

Volatility and High Thermal Stability in Tantalum Complexes Containing Imido, Amidinate, and Halide or Dialkylamide Ligands

Processing and properties of ferroelectric relaxor lead scandium tantalate Pb(Sc1/2Ta1/2)O3 thin films

Growth of Tantalum(V) Oxide Films by Atomic Layer Deposition Using the Highly Thermally Stable Precursor Ta(NtBu)(iPrNC(Me)NiPr)2(NMe2)

Contact Info

Product

Resources

About

Processing and properties of ferroelectric relaxor lead scandium tantalate Pb(Sc_1/2Ta_1/2)O₃ thin films

Growth of Tantalum(V) Oxide Films by Atomic Layer Deposition Using the Highly Thermally Stable Precursor Ta(NtBu)(iPrNC(Me)NiPr)₂(NMe₂)