This paper reports on the design and simulation of a new valve-less pump for use in microfluidic applications. The
simple-structure micropump comprises a piezoelectric Pb(Zr,Ti)O<sub>3</sub> (PZT) - Si diaphragm and flow channels which are
fabricated using silicon micromachining techniques. The silicon diaphragm (5×5×0.05mm<sup>3</sup>) is driven by the PZT (45-μm
thick) actuator that has quick response time and large driving force with low power consumption. A key technology to
realize the pump diaphragm is the PZT-Si bonding process using a thin gold film as an intermediate layer. Under
fabrication conditions of 550°C and 0.8 MPa, the strength of the bonding was experimentally validated to be 13 MPa.
The maximum displacement of the diaphragm was measured to be 3 μm<sub>0-P</sub> with driving voltage of 30 V<sub>p-p</sub> at resonance
frequency of 10 kHz. Structural analysis of the diaphragm was done in terms of three-dimensional model using
commercial software ANSYS. The flow channels are easily fabricated by silicon etching process. Design of flow
channels focused on a cross junction formed by neck of the pump chamber, one outlet and two opposite inlet channels.
This structure allows a difference in fluidic resistance and fluidic momentum to be created inside the channels during
each pump vibration cycle. Two designs of the devices which have different channel depths, namely type A and type B,
was investigated. Flow simulation was done by numerical transient model (using ANSYS-Fluent), in which only the
measured deformation of the PZT diagram is applied and therefore no other assumptions are required. The results
showed that the mass flow rate of the type A is 0.129×10<sup>-6</sup> kg/s (mean flow rate of 6.3 ml/min) and that of type B is
1.65×10<sup>-6</sup> kg/s (mean flow rate of 80.8 ml/min).