Automated poling and testing

A system for automated poling and testing of the devices at wafer level has been developed. The wafer is mounted on a programmable xyz-table with a heating chuck. The devices are addressed sequentially and can be poled and tested individually at up to 160 °C. C(V) and I(V) measurements are routinely carried out and the system is to be integrated with an aixACCT TF2000 ferroelectric analyzer that will enable automatic measurements, including:
• polarisation hysteresis,
• fatigue behaviour,
• impedance sweeps (for electromechanical characterisation including determination of mechanical resonances).

New testing method

The project has developed a new 4-point bending set-up for measurement of piezoelectric and dielectric charges at a substrate that is bent into a constant curvature [1]. The bending amplitude is measured by an interferometer and is used for determining the transversal piezoelectric charge coefficient, e31,f. Samples for this test set-up have been included in the test wafer. The same set-up and samples can also be used for d33 measurements.

Automated probe station for automatic poling and mapping of device performance across a wafer