A ZnO thin-film driven microcantilever for nanoscale actuation and sensing

Figures & data

Table 1. Deposition parameters of ZnO thin film

Parameters	Value
Target	ZnO (99.99%, 50 mm (D))
TSD (mm)	100
Substrate	Au/SiO2/Si
Substrate temperature	Room temperature
Substrate rotational speed (rpm)	30
RF power (W)	30, 50, 70, 90, 110
Working pressure (Pa)	0.6, 0.8, 1.1, 1.3, 1.5
O2/(O2 + Ar) (%)	0, 10, 25, 35, 50
Deposition time (hr)	2

Figure 1. Deposition rate of ZnO thin film with respect to the RF power in the magnetron sputtering system.

Figure 3. SEM image of the cross-sectional ZnO thin film.

Figure 2. XRD patterns of ZnO thin film under: (a) various working pressure and (b) various gas ratios.

Table 2. Design specifications of the ZnO piezoelectric cantilever

Thickness of silicon t s (μm)	Thickness of ZnO t p (μm)	Length of cantilever L (μm)	Width of cantilever w (μm)	Resonant frequency fn (kHz)	Actuating sensitivity δ/V (nm/V)	Sensing sensitivity V/a (mV/g)
34	1	1000	500	50	13.5	53.6

Figure 5. Fabricated ZnO cantilever.

Figure 4. Fabrication process flow: (a) oxidation, (b) Au/Ti deposition, (c) ZnO deposition, (d) Au/Ti deposition, (e) front-side etching, and (f) back-side etching.

Figure 6. Impedance and phase angle.

Figure 7. Characterization setup: (a) actuator characterization and (b) sensor characterization.

Figure 8. Actuator response at 15 kHz: (a) driving voltage and (b) tip deflection.

Figure 9. Tip deflection versus driving voltage.

Figure 11. Cantilever output voltage versus base acceleration.

Figure 10. Sensor response at 15 kHz: (a) acceleration and (b) output voltage.

Figure 12. Calculated d ₃₁ versus driving voltage.