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Bosch semiconductors for Automotive

PZT (Lead Zirconate Titanate)

PZT is a piezoelectric material which is ideal for an actuator. PZT can be deposited by solgel or sputtering. In comparison to solgel is sputtering a typical semiconductor approach. The sputtered material is well defined and not contaminated with residuals from the used solvents. Bosch is working with sputtered PZT since 2014. During this phase quality and control of Bosch’s PZT did reach high quality standard with regard to reproducibility, defectivity and reliability.

State of the art 8” PVD equipment:

  • Ulvac
  • Process ready for mass production
  • Deposition temperature between 450° and 490°C, very low (!)

Typical material properties

  • PZT: e31: -13 …-15 C/m2 @1000nm and 200 kV/cm. Keep in mind, that those results depend strongly on the measurement conditions. We compared physically Bosch’s PZT with the PZT from main competitors. Result: Bosch’s PZT is world leading quality
  • Thickness range: 500 – 4000 nm (depends on application), non-uniformity: < 10%
PZT stack
PZT stack

Process Integration of a complex PZT Stack:

  • Adhesion layer
  • Pt electrodes
  • Seed layer
  • H/H2O barrier
  • Protection layer

Specific Metrology, see below:

  • aixHALT test bench for lifetime under bias
  • aixACCT tool for d33 and e31 measurement
  • Ellipsometry for thickness and material control
  • PZT structure
    PZT structure