Analysis of the stress and interfacial reactions in Pt/Ti/SiO2/Si for use with ferroelectric thin films

Madsen, Lynnette D.; Weaver, Louise; Ljungcrantz, H.; Clark, Alison J.

doi:10.1007/s11664-998-0171-7

Cited by 11 publications

(5 citation statements)

References 24 publications

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“…Pt-Ti intermetallics will occur, in general, due to interdiffusion at elevated temperatures in diffusion couples (e.g., as shown by Tisone and Drobek [ 34 ] and even after annealing of crystallized fi lms deposited on Pt/Ti substrates (e.g., as shown by Madsen et al in stacks of PbTiO 3 /Pt/Ti/ SiO 2 /Si annealed at temperatures as low as 400 °C [ 15 ] . Their intentional infl uence on nucleation and growth of the perovskite phase has also been demonstrated through designed experiments.…”

Section: Resultsmentioning

confidence: 99%

Combined Experimental and Computational Methods Reveal the Evolution of Buried Interfaces during Synthesis of Ferroelectric Thin Films

Jones

LeBeau

Nikkel

et al. 2015

Adv Materials Inter

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(1 of 10) 1500181 wileyonlinelibrary.com IntroductionFerroelectric thin fi lms have broad application in society ranging from nonvolatile memories to microrobotics and integrated capacitors. As the sizes of devices and the thicknesses of fi lms decrease, the specifi c surface and interfacial areas increase signifi cantly. At these progressively smaller length scales, interfacial phenomena such as interdiffusion and interface reactions are promoted and can have benefi cial or deleterious consequences on the resultant fi lm and device properties and functionality. [1][2][3][4] Thus, an understanding of interfacial phenomena between dissimilar materials is of paramount importance in materials and devices of small length scale.Solution-based chemical routes have become effective for the synthesis of ferroelectric lead zirconate titanate (PZT) thin fi lms on diverse substrates. [5][6][7][8] In these routes, a solution is spin cast on a substrate and then subsequently heated to induce crystallization of the ferroelectric fi lm. For Pb-based ferroelectric fi lms Understanding interfaces between dissimilar materials is crucial to the development of modern technologies, for example, semiconductor-dielectric and thermoelectric-semiconductor interfaces in emerging electronic devices. However, the structural characterization of buried interfaces is challenging because many measurement techniques are surface sensitive by design. When interested in interface evolution during synthesis, the experimental challenges multiply and often necessitate in situ techniques. For solution-derived lead zirconate titanate (PZT) ferroelectric thin fi lms, the evolution of buried interfaces during synthesis (including dielectricmetal and metal-metal) is thought to dramatically infl uence the resultant dielectric and ferroelectric properties. In the present work, multiple experimental and computational methods are combined to characterize interface evolution during synthesis of ferroelectric PZT fi lms on platinized Si wafers-including in situ X-ray diffraction during thermal treatment, aberration-corrected scanning transmission electron microscopy of samples quenched from various synthesis states, and calculations using density functional theory. Substantial interactions at buried interfaces in the PZT/Pt/Ti/SiO x /Si heterostructure are observed and discussed relative to their role(s) in the synthesis process. The results prove that perovskite PZT nucleates directly from the platinum (111)-oriented bottom electrode and reveal the roles of Pb and O diffusion and intermetallic Pt 3 Pb and Pt 3 Ti phases.

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Section: Resultsmentioning

confidence: 99%

Combined Experimental and Computational Methods Reveal the Evolution of Buried Interfaces during Synthesis of Ferroelectric Thin Films

Jones

LeBeau

Nikkel

et al. 2015

Adv Materials Inter

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“…Plastic deformation of Pt films on Ti including void generation and island formation have been observed in annealing experiments 5,7,[20][21][22][23] at temperatures as low as 450 C. 21 Annealing of Pt/Ti bilayer metallizations in O containing atmosphere and at elevated temperatures allows for O and Ti diffusion and their reaction to TiO x which also happens in the Pt layer. 7,8,24,25 This kind of phase intermixing due to diffusion of Ti and reaction with O in Pt grain boundaries has been reported before.…”

Section: Discussionmentioning

confidence: 99%

“…4 Furthermore, the electrode material should possess a large work function to suppress charge injection and leakage currents and ohmic losses in the electrodes should be as small as possible. One electrode material which fulfills these prerequisites is Pt, mainly due to its resistance to oxidation and its high electrical conductivity 5 as well as its high Schottky barrier. 6 However, Pt adheres poorly to SiO 2 , which hinders the successful implementation of these devices into Si-based electronics.…”

Section: Introductionmentioning

confidence: 99%

“…Combinations of an adhesion layer (mainly Ti) and possibly a diffusion barrier have been suggested in the past in the search for suitable electrodes for PZT (Pb[Zr x Ti 1x ]O 3 ). 5,7,8 In this paper, we present the results of microstructural investigations of the influence of the interfacial interaction between the adhesion layer, diffusion barrier, and Pt bottom electrode during BSTO growth. The growth temperature is a key parameter for the BSTO acoustic performance.…”

Section: Introductionmentioning

confidence: 99%

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Adhesion layer-bottom electrode interaction during BaxSr1−xTiO3 growth as a limiting factor for device performance

Löffler

Vorobiev

Zeng

et al. 2012

Journal of Applied Physics

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Related Articles Thickness driven stabilization of saw-tooth-like domains upon phase transitions in ferroelectric thin films with depletion charges J. Appl. Phys. 111, 064105 (2012) Correlation between growth dynamics and dielectric properties of epitaxial BaTiO3 films Appl. Phys. Lett. 100, 102904 (2012) Strong red emission in lead-free ferroelectric Pr3+-doped Na0.5Bi0.5TiO3 thin films without the need of charge compensation J. Appl. Phys. 110, 034102 (2011) Influence of thermal stresses on the electrocaloric properties of ferroelectric films Appl.

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“…Higher piezoelectric properties may be reached by doping methods [4] and we will show that the membrane actuation efficiency may be improved through the actuator layout optimization. Moreover, the stresses in thin PZT and Ti/Pt films have been measured by many authors [5,6] and it is known that the membrane pressure response and thermal drifts can be affected by its stress state, as has been shown for silicon membranes [7,8]. To reduce the influence of these stresses, the actuator geometry has to be reduced compared to that of the membrane.…”

Section: Introductionmentioning

confidence: 99%

Simple and Low Cost Patterning Process for Sputtered Pb(Zr,Ti)O₃ Thin Films and Electrodes for Membrane-Based Microsystems Applications

Millon¹,

Malhaire

Defaÿ

et al. 2000

MRS Proc.

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Micromachined silicon membranes actuated by a piezoelectric thin film are of great interest for microfluidic or ultrasonic applications. In this paper, we present a simple and low cost patterning process for sputtered Ti and Pt electrodes and Pb(Zr,Ti)O 3 thin films using lift-off and a wet HCl etching methods respectively. We have showed by finite element analysis the incentive to pattern electrodes in order to get higher actuation performances. Moreover, in order to reduce the stress on the diaphragm, the PZT film has been also patterned. We propose an optimized flow chart taking into account the different material properties in the multi-layer stack constituting the actuator and the need of a PZT crystallization annealing. To show the influence of the actuator layout, finite element models of a 20 µm thick, 3 x 3 mm 2 silicon membrane with variable electrode design, actuated by a 1 µm PZT (10 V bias) thin film have been developed. We found a maximum deflection for a 1.7 mm side length square electrode located at the membrane center. Sputtering was achieved on a non-heated silicon substrate, in pure Argon, using a stoichiometric PZT target. The metallic electrodes have been structured by standard liftoff technique. Different concentrations of HCl [4 % -35 %] with temperature up to 90°C have been tested for PZT patterning. Well defined PZT microstructures were better achieved by wet etching of unannealed PZT film on SiO 2 or Pt (HCl 35%, room temperature). The etching rate was 40 nm.s -1 . The presence of the perovskyte phase in the PZT films after a 700°C, 30 s RTA in air, has been checked by X-ray measurements. Finally, the silicon membranes have been realized by anisotropic chemical etching in an aqueous KOH (40 %, 60°C) solution. Membrane deflection under low bias have been successfully tested.

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Analysis of the stress and interfacial reactions in Pt/Ti/SiO2/Si for use with ferroelectric thin films

Cited by 11 publications

References 24 publications

Combined Experimental and Computational Methods Reveal the Evolution of Buried Interfaces during Synthesis of Ferroelectric Thin Films

Combined Experimental and Computational Methods Reveal the Evolution of Buried Interfaces during Synthesis of Ferroelectric Thin Films

Adhesion layer-bottom electrode interaction during BaxSr1−xTiO3 growth as a limiting factor for device performance

Simple and Low Cost Patterning Process for Sputtered Pb(Zr,Ti)O₃ Thin Films and Electrodes for Membrane-Based Microsystems Applications

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Analysis of the stress and interfacial reactions in Pt/Ti/SiO2/Si for use with ferroelectric thin films

Cited by 11 publications

References 24 publications

Combined Experimental and Computational Methods Reveal the Evolution of Buried Interfaces during Synthesis of Ferroelectric Thin Films

Combined Experimental and Computational Methods Reveal the Evolution of Buried Interfaces during Synthesis of Ferroelectric Thin Films

Adhesion layer-bottom electrode interaction during BaxSr1−xTiO3 growth as a limiting factor for device performance

Simple and Low Cost Patterning Process for Sputtered Pb(Zr,Ti)O3 Thin Films and Electrodes for Membrane-Based Microsystems Applications

Contact Info

Product

Resources

About

Simple and Low Cost Patterning Process for Sputtered Pb(Zr,Ti)O₃ Thin Films and Electrodes for Membrane-Based Microsystems Applications