Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras

Technology Category/ Market

Category – Advanced materials

Applications –Sensors, Semiconductors, acoustic devices, power harvesting systems

Industry – Electrical, Manufacturing

Market -Piezoelectric Materials Market size was valued at USD 29.23 billion in 2021 and is poised to grow from USD 30.9 billion in 2022 to USD 48.14 billion by 2030, growing at a CAGR of 5.7% in the forecast period (2023-2030).

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Problem Statement

  • PZT is desirable for fabricating electrical devices like power harvesters, sensors, surface acoustic wave devices etc. due to its favorable electrical properties
  • PZT in thin film form exhibits lower leakage current density, higher remanent polarization for fast polarization switching, and can sustain high dielectric strength compared to bulk polycrystalline ceramics.
  • Developing PZT thin films over large areas is challenging due to the volatile nature of Pb at high processing temperatures and the need to maintain stoichiometry across the entire deposited area.

Technology

The present invention discloses a method involves the fabrication of high-quality large-scale PbZrxTi1-xO3(PZT) thin films on a platinum-coated silicon substrate.

Composition and Preparation:

  • PZT thin films are prepared from stoichiometric quantities of the oxide powders PbO, ZrO2, and TiO2 through a solid-state reaction route

Raster Mechanism:

  • A programmable raster mirror is utilized and positioned above the quartz window for precision and deposition

Laser Beam Scanning:

  • The programmable rastered laser beam is fixed with a scan rate of 300 steps/sec

Scanning Pattern:

  • starts from the edge of the target, moves towards the center of the 2-inch rotating PZT target, and then reverses its direction.

Incidence Angle:

  • The laser beam is directed onto the target with a specific incidence  angle of 45 degrees.

Chamber Conditions and Annealing:

  • Partial pressure of 0.3 mbar of oxygen (O2) is maintained inside the chamber, followed by deposition, and 60-minute post-deposition annealing to form PZT thin films
  • In the said method the mirror is rastered across the large diameter of the ablated target, contributing to the precision of the deposition process.
  • The said programmable rastered laser beam sweeps across the rotating target, covering the entire 2-inch target surface area.
  • Further, the crystalline large-area PZT thin films acquired by the said method, wherein the cooling rate during annealing is set at 10 degrees Celsius per minute
  • The lateral homogeneity over the large area has been demonstrated by recording polarization maps at the different locations with different electrode sizes of the polycrystalline films

Key Features/ Value Proposition

Technical Perspective:

  • The invention relates to ferroelectric large area PZT thin films, grown on oriented Pt coated Si substrate using off-axis pulsed laser deposition (PLD) with a beam rastering mechanism.
  • This method combines specific deposition conditions, scanning patterns, and post-treatment processes to produce large-scale, high-quality PZT thin films

User Perspective:

  • Large area PZT thin films are used in under-water SONAR devices, power harvester, sensors, acoustic devices, MEMS etc
  • The interface between the as-grown large PZT thin films and the Pt coated Si substrate is well defined, flat and sharp

Questions about this Technology?

Contact For Licensing

sm-marketing@imail.iitm.ac.in
ipoffice2@iitm.ac.in

Research Lab

Prof. RAMACHANDRA RAO M S

Prof. SETHUPATHI K

Department. of Physics

Intellectual Property

  • IITM IDF Ref. 1574
  • IN 458560-Granted

Technology Readiness Level

TRL-3

Experimental Proof of Concept 

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