In this work, the structural stability and sealing capability of silicon nitride, amorphous silicon, and silicon dioxide films in large-area ( $750~\mu $ m x $200~\mu $ m) thin-film packaging are investigated. A process flow entirely at low temperature ( $\le 200~^{\circ }$ C) is used to fabricate the thin-film packaging, including plasma-enhanced chemical vapor deposition (PECVD) for silicon nitride capping and various sealing layers of silicon nitride, amorphous silicon, and silicon dioxide. Plasma frequency is varied using a mixed procedure to obtain a low tensile stress of 2.2 MPa for the silicon nitride capping layer, whereas higher tensile and compressive stress values are obtained for various sealing layers deposited at low and high frequencies, respectively. Deflections in the range 10-515 nm are measured for the fabricated thin-film packaging structures under the application of different point forces by mechanical profilometry. Young’s modulus of sealing layers is measured by indentation technique and used, together with the residual stress values and Poisson’s ratios, as input parameters for the Finite Element Method (FEM) modelling of measured deflections. An ad-hoc procedure is developed to combine plasma focused ion beam (PFIB) and scanning electron microscopy (SEM) techniques, allowing to inspect the conformality properties of the different sealing layers. A good agreement is found between the experimental results and modelling data, pointing out that silicon nitride sealing layer with thickness of $5~\mu $ m provides the best performance in terms of stiffness and sealing of 3- $\mu $ m-sized cap holes situated in both the planar top and the sidewalls of packaging structures. [2026-0117]
This paper presents a novel anchoring for polysilicon-based movable microstructures that considerably increases the resistance of MEMS to large out-of-plane deflections or torsional distortions. Basically, for that the polysilicon within the anchoring of the movable microstructure is reinforced and the presence of silicon oxide within the area of highest stress is avoided. A process is described which enables the fabrication of substrates with locally varying polysilicon thickness over a range of several tens of micrometers. In addition, rounding of critical corners and edges is implemented. The novel anchoring concept is modelled using FEM simulation and validated experimentally. Test devices with movable microstructures featuring the novel reinforced anchoring withstand 3.5 times higher mechanical loads compared to identical test devices with state-of-the-art anchoring. The simulations suggest that MEMS with reinforced anchoring fulfil the shock stability requirements of industry standards to an unprecedented degree. At the same time the influence of process-induced dimensional deviations on their mechanical properties is reduced.[2026-0103]
This letter reports a high-symmetry micro-shell whole-angle gyroscope using a time-multiplexed analog front-end (AFE) ASIC. The micro-shell resonator provides mechanical symmetry with a mode split of 9 mHz and a damping anisotropy of 1.24%, while maintaining a quality factor above 1.32 million. At the circuit level, time multiplexing suppresses X/Y gain mismatch by sharing the signal path. Phase mismatch introduced by the switching network is reduced through a fully differential implementation, matched layout, and path-specific switch-sizing optimization. Together, these circuit-symmetry measures reduce the phase mismatch from 1.02 deg to 0.27 deg, thereby lowering the angle-dependent bias (ADB) from 421.90 deg/h to 17.57 deg/h. With additional electrostatic frequency tuning and digital phase compensation applied on top of the mechanical- and circuit-symmetry measures, the complete gyroscope achieves an ADB of 0.35 deg/h, an angle random walk of 0.003 deg/ $\sqrt {\mathrm {h}}$ , and a bias instability of 0.055 deg/h, demonstrating state-of-the-art performance for a high-symmetry whole-angle micro gyroscope.[2026-0127]
Though widely used for research, the scanning tunneling microscope (STM) has not been adopted as a commercial nanofabrication tool due to its low scan speed and throughput. One of the key contributors to the STMs sluggishness is the piezoelectric nanopositioner (piezotube) it employs to move the tip over the sample. The bulkiness of the piezotube limits the system bandwidth to 1 kHz, restricting achievable scan speeds. This paper presents a design for a micro-electromechanical system (MEMS) nanopositioner for the STM that replaces the piezotube with an electrostatic actuator that has an order of magnitude higher bandwidth. To further increase the STMs throughput, this design also features two integrated tips that streamline fabrication with a batch process. The proposed MEMS design is shown to achieve $5.7~{\mu }$ m of displacement in the Z-axis and have a first in-plane resonance of 15.8 kHz. The design is experimentally tested by establishing a stable tunneling current with each STM tip individually and concurrently on a graphite sample in ambient conditions.[2026-0065]
This paper presents optimized single-phase unidirectional transducers (SPUDTs) and acoustic delay lines (ADLs) based on Love-mode surface acoustic waves (SAWs) on a 300nm X-cut LiNbO3-on-SiC substrate. The proposed designs refine conventional DART and EWC-SPUDT configurations by incorporating precise considerations of additional electrical reflections introduced by piezoelectric regeneration. By fine-tuning the electrode width and relative positions, the improved SPUDTs achieve significantly enhanced unidirectionality without increasing fabrication complexity. Experimental results demonstrate that the optimized designs reduce insertion loss by approximately 1dB compared to conventional SPUDTs, while maintaining a 3-dB bandwidth exceeding 5% at an operating frequency near 2.5GHz. These improvements, coupled with the inherent advantages of the LiNbO3-on-SiC platform—high acoustic velocity, large electromechanical coupling coefficient, and favorable thermal and mechanical stability—make the proposed designs particularly suitable for advanced applications such as pulse compression, signal filtering, delay matching, sensing, and microfluidics. [2026-0059]
