Design and Fabrication of a Metal-Silicon Actuator With Low Voltage, Low Power Consumption and Large Displacement

The V-shaped electrothermal actuator has gained significant popularity as it was demonstrated to be a compact, stable and high rectilinear displacement device. However, existing electrothermal actuators usually require the driven voltage as high as several tens of volts to realize large displacements, imposing restrictions on the actuator’s integration in miniature mobile mechatronic systems. The paper presents a V-shaped metal-silicon actuator with low voltage, low power consumption and large displacement. The electro-thermal conversion and heat conduction mechanism of the actuator are improved by optimizing the architecture design of the actuator. An innovative method utilizing the double-sided inductively coupled plasma etching technique is developed for the fabrication. The motion of the actuator is characterized with a microscope-based dynamic test system. Finite element analysis is conducted to verify the device design and experimental results. The transient dynamic behaviour of the actuator is modelled for future control strategy. A rectilinear displacement as high as
$80.7~\mu \text{m}$
is achieved at a voltage of 4.0 V and power of 1.12 W. The displacement per unit length to voltage ratio of the metal-silicon actuator is the largest among existing silicon actuators. The displacement per unit length to power of the actuator is also comparative to the highest value of existing actuators, demonstrating that the metal-silicon actuator can achieve large displacement with low voltage and power consumption. The proposed actuator has great potential for the applications in the miniature mechatronic systems such as cell phone, camera, safety and arming device. [2021-0048]