A 2D scanning micromirror with piezoelectric thin film aluminum nitride (AlN), separately used as actuator and sensor material, is presented. For endoscopic applications, such as fluorescence microscopy, the devices have a mirror plate diameter of 0.7 mm with a 4 mm² chip footprint. After an initial design optimization procedure, two micromirror designs were realized. Different spring parameters for x- and y-tilt were chosen to generate spiral (Design 1) or Lissajous (Design 2) scan patterns. An additional layout, with integrated tilt angle sensors, was introduced (Design 1-S) to enable a closed-loop control. The micromirror devices were monolithically fabricated in 150 mm silicon-on-insulator (SOI) technology. Si (111) was used as the device silicon layer to support a high C-axis oriented growth of AlN. The fabricated micromirror devices were characterized in terms of their scanning and sensor characteristics in air. A scan angle of 91.2° was reached for Design 1 at 13 834 Hz and 50 V. For Design 2 a scan angle of 92.4° at 12 060 Hz, and 123.9° at 13 145 Hz, was reached at 50 V for the x- and y-axis, respectively. The desired 2D scan patterns were successfully generated. A sensor angle sensitivity of 1.9 pC/° was achieved.

Pulsed DC magnetron sputtered aluminum nitride (AlN) thin films are prepared on several seed layers and at different sputtering conditions. The piezoelectric c-axis (002) orientation of the AlN is analyzed with X-ray diffraction method. The transverse piezoelectric coefficient d₃₁ is determined with a Laser-Doppler-Vibrometer at cantilevers and membranes by analytical calculations and finite element method. Additionally, thin film AlN on bulk silicon is used to characterize the longitudinal piezoelectric charge coefficient d₃₃.

In recent years, micro-electromechanical systems (MEMSs) have found broad applications in various sensors. However, aside from quartz crystal microbalances, they have not yet been utilized in plasma analysis. Building on previous work with piezoelectric MEMS, the functionality of a MEMS-based sensor system capable of measuring the ion angular distribution function on the wafer holder surface is demonstrated. To enable this functionality, an array of high aspect ratio holes was added to the tiltable silicon plate of a piezoelectric MEMS. These holes allow for the filtering of incoming ions based on their angle perpendicular to the surface of the tiltable element. An algorithm was developed to fit the width and mean of the ion angular distribution function (IADF) based on the RMS ion current for various MEMS amplitudes. Compared to previously used methods for measuring the IADF, the MEMS presented in this paper represents a significant miniaturization. This work is the first to successfully characterize the angular distribution function of ions using a MEMS.

This paper is dedicated to the integration of photonic components into Micro-Electro-Mechanical Systems (MEMS) to develop high-performance inertial sensors, particularly for autonomous vehicle applications. Traditional MEMS sensors face limitations in electrical signal conversion. Optomechanical sensing, which couples mechanical motion with optical detection, offers enhanced sensitivity, reduced noise, and improved stability. By embedding optical components directly into the MEMS structure, we aim to address these advantages for improved performance, to be first demonstrated for a sensor/actuator test structure compatible for acceleration measurement. The paper describes in detail the design and fabrication process, incorporating electrostatic actuators, sensors and optical ring resonators into OptoMEMS. Comprehensive simulations use ANSYS Mechanical for mechanical and electrostatic part with a coupling to ANSYS Lumerical to convert mechanical deformations into optical resonance shifts. Preliminary fabrication and measurement results validate the simulation concept, demonstrating the feasibility of this integrated optomechanical approach.