The relatively low piezoelectric constant of aluminum nitride (AlN) piezoelectric film limits the development and application of the acoustic field performance of AlN-based micromachined ultrasonic transducers; thus, in this study we establish a mid- to low-frequency transducer unit model to address this problem. The transducer operates at 4.5 MHz, and the construction of a clamped structure is first investigated to ensure the feasibility of performance analysis. Secondly, the effectiveness of the optimized upper electrode distribution proposed in this paper in improving the acoustic field radiation of the array element is also compared with the original structure. Finally, the influence of the optimized electrode geometry parameters on the acoustic wave direction is analyzed. The finite element simulations are performed in the COMSOL Multiphysics (COMSOL) software and post-processing results are analyzed. Based on the simulation results, the proposed optimal distribution of the upper electrode makes the radiation beam uniform and symmetrical in the case of both the clamped model and the optimized structure model. In the case of the upper electrode radius of 28 µm, this electrode division operation makes the unit vibration mode switching in the frequency range more moderate. The sound field radiation improvement of the proposed optimized structure model is better than that of the clamped structure.

This study illustrates a type of novel device. Integrating fin field-effect transistors (FinFETs) with current silicon-on-insulator (SOI) wafers provides an excellent platform to fabricate advanced specific devices. An SOI FinFET device consists of three independent gates. By connecting the various gates, multiple working modes are obtained. Compared with traditional FinFETs, the multi-enhanced operation gate fin field-effect transistor in this study combines independent gates by connecting the selection modes; thus, a possible operation can be performed to attain a FinFET with five equivalent working states in only one device. This novel function can enable the device to work with multiple specific voltages and currents by connecting the corresponding gate combinations, augmenting the integrated degrees and shifting the working modes, thereby meeting the different needs of high-speed, low-power, and other potential applications. Further, the potential applications are highlighted.