Partial-electroded ZnO pyroelectric sensors for responsivity improvement

The design, MEMS fabrication and characterization of the ZnO pyroelectric sensor for improvement of responsivity are presented. Three groups of the sensor with various layer thickness, effective area, partially and fully covered electrode (FCE) were fabricated and investigated. The partially covered electrode (PCE) covers 50–65% area of the exposed surface for incident energy absorption. The un-covered ZnO will directly receive the incident laser energy and improve the absorption efficiency of the sensor. The measured data show that the partial-electroded sensors exhibits at least 4 times higher responsivity in the frequency range of 10–1000 Hz than the full-electroded sensors. The effects of other design parameters such as thickness of ZnO, SiO2 and Si3N4 on the responsivity are also discussed.