Beyond standard polycrystalline PZT, Silex has developed two process capabilities that push the boundaries of what is achievable with thin-film piezoelectrics: epitaxial PZT and stress-tunable PZT stacks. Epitaxial PZT. Conventional sputtered PZT films are polycrystalline: the grains are randomly oriented, which introduces variability in piezoelectric response across the wafer. Epitaxial PZT addresses this by growing the film with a controlled, highly ordered crystallographic structure using a seed layer approach. The result is a film with near-single-crystal alignment, delivering a more linear piezoelectric coefficient (e31f), a lower coercive field, and more predictable electromechanical behaviour. “Epitaxial PZT changes the conversation around predictability,” Svedin explains. Controlling the crystallographic structure that precisely means the simulation and physical device align in ways that are very difficult to achieve with conventional polycrystalline films. “That has real implications for how quickly a customer can move from design to working prototype,” he adds. For applications where consistency of response and accuracy of device modelling are critical – such as high-precision sensing or medical ultrasound – epitaxial PZT represents a meaningful step forward in process control.
