Table 2.

The thickness of each material layer in MIS-process PMUT device.

Material Layer	Material	Thickness (μm)
Elastic layer	Polysilicon	4
Elastic layer	(111) Silicon	6
Insulation layer	TEOS–silicon oxide	0.3
Electrode layer	Molybdenum	0.3
Piezoelectric layer	Aluminum nitride	2
Etching mask layer	PECVD silicon oxide	0.3