Multilayer piezoelectric ceramics are composed of several layers of piezoelectric materials arranged alternately with internal electrodes. The internal electrodes are sequentially positioned as positive and negative electrodes, with all positive electrodes connected to an external electrode on one side of the component. The negative electrode is connected to the other side of the component. Compared with single-layer piezoelectric ceramics, the great advantage of multi-layer piezoelectric ceramics is that they can reduce the applied voltage when achieving the same displacement as single-layer piezoelectric ceramics. The displacement of single-layer piezoelectric ceramics is equal to the piezoelectric constant d33 multiplied by the voltage, while the displacement of multi-layer piezoelectric ceramics is equal to the piezoelectric constant d33 multiplied by the voltage multiplied by the number of layers.

Scanning tunneling microscope (STEM) uses piezoelectric ceramic technology, and it is difficult to achieve high-precision scanning of the sample surface by controlling the needle tip with ordinary mechanical control. Piezoelectric ceramic materials can convert voltage signals ranging from 1mV to 1000V into displacements of tens of nanometers to a few micrometers in a simple manner.

The quality requirements for multi-layer piezoelectric ceramic devices are high, and their internal multi-layer structure needs to be observed using scanning electron microscopy (SEM), such as whether each layer of ceramic has defects, whether the thickness of the multi-layer ceramic is uniform, and whether the silver layer used as an electrode is evenly covered. These structures affect the service life of the device.