Hydraulically amplified self-healing electrostatic (HASEL) actuators provide a framework to create soft robots with excellent strength, speed, and versatility. Peano-HASEL actuators produce fast and powerful linear contraction and achieve a maximum strain of ~15%. However, skeletal muscle achieves ~20% strain on average. Here, high strain Peano-HASELs (HS-Peano-HASELs) are introduced that achieve linear contraction up to ~ 24%. We investigate a wide range of performance metrics for HS-Peano-HASELs constructed with different materials and geometries. Furthermore, HS-Peano-HASELs are used as a tubular pump, resembling the primordial heart of an ascidian. Additionally, a strain amplifying pulley system is introduced to increase the maximum strain to ~42%.
Recently developed hydraulically amplified self-healing electrostatic (HASEL) actuators can utilize diverse material systems to create high-performance, muscle-mimetic actuators that can be tailored to specific applications. Initial versions of HASEL required cumbersome high voltage driving electronics and utilized a manual fabrication technique which was not easily adjusted to iterate designs. This presentation will describe a versatile and accessible fabrication technique using a computer numerically controlled (CNC) heat sealing machine to rapidly prototype complex designs of HASEL actuators. With this simple fabrication technique, we can create high performance HASELs which offer a variety of actuation modes. These actuators harness electrostatic zipping mechanisms to reduce operating voltages and facilitate a smooth actuation response to input voltage. Moreover, these HASELs feature linear strains over 100%, specific power of 816 W/kg, and cut-off frequencies of 125 Hz; these metrics enable actuators which are fast and powerful enough to jump. Using these devices, we create a continuum actuator capable of three-dimensional articulation and an active surface with programmable morphology. Additionally, we develop a portable electronics package for untethered operation of these soft robotic devices. This presentation will highlight the diverse design freedom inherent to HASEL actuators in terms of material selection and actuator design.
KEYWORDS: Etching, Multilayers, Wet etching, Ultrasonics, Signal processing, Line edge roughness, Scanning electron microscopy, Transmission electron microscopy, Calibration, Reactive ion etching
Background: The multilayer gratings are considered as the potential length-standard-traceable lateral scales for calibrating the next-generation critical dimension scanning electron microscope (CD-SEM) magnification. As a key step in the fabrication of multilayer gratings, selective wet etching determines the final grating structure formation. However, the effects of the etching process parameters on the multilayer gratings in several nanometer scales have not been reported in detail. Aim: By optimizing the process of selective wet etching, we should fabricate high-aspect-ratio and uniform multilayer gratings to obtain high-contrast secondary electron signals and stable secondary electron images while also obtaining measurement accuracy from the small line edge roughness. Approach: Based on the analysis of the important factors in the etching process and SEM and TEM measurement results, we evaluate the effects of ultrasonic agitation, HF acid concentration, etch time, and linewidth scale on the aspect-ratio and uniform of multilayer gratings. Results: We recommend to etching the multilayer films with an HF acid concentration of about 2% during the ultrasonic agitation for uniformity. Moreover, selective wet etching reaction is limited by scale when the linewidth is below 20 nm. Despite the fact that the grating structure is fragile and easy to be broken down, for linewidths of about 10 and 5 nm, the aspect ratio of multilayer gratings can reach about 3 and 2, respectively. Conclusions: By focusing on the optimum conditions of ultrasonic agitation, HF acid concentration, and linewidth scale in the selective wet etching, selective wet etching can be used to fabricate high-aspect-ratio and uniform multilayer gratings with linewidth below 20 nm.
One-dimensional multilayer gratings were prepared by four steps. A periodic Si/SiO2 multilayer was firstly deposited on Si substrate using a magnetron sputtering coating process. Then, the multilayer was been bonded and split into small pieces by diamond wire cutting. The side-wall of the cut sample was subsequently grinded and polished until the surface roughness was less than 1nm. Finally, the SiO2 layers were selective etched using hydrofluoric acid to form the grating structure. In the above steps, special attentions were given to optimize the etching processes to achieve a uniform and smooth grating pattern. Transmission electron microscope (TEM) was used to characterize the multilayer gratings. The pitch size of the grating was evaluated by an offline image analysis algorithm and optimized processes are discussed.
KEYWORDS: Metrology, Chromium, Atomic force microscopy, Calibration, Chemical species, Laser stabilization, Scanning electron microscopy, Standards development, Manufacturing, Atomic force microscope
Nanometric lateral standards are essential to nanometrology. Using laser-focused atomic deposition, a one-dimensional (1D) grating has been manufactured. The pitch of the grating is 212.8 nm, which can be traced to the laser wavelength that is accurately locked to the 52Cr atomic resonance transition 7S3 →7P40. In this paper, the uniformity rather than the pitch accuracy of the 1D grating was evaluated using atomic force microscope (AFM). Based on the center-of-gravity method, the average pitch and the nonuniformity of the grating pitch were calculated. The results show that the average pitch of the grating is 213.2 nm which deviates from the design pitch due to the calibration of AFM, and the nonuniformity of the grating is 0.1 nm. The results preliminarily prove that 1D grating fabricated by laser-focused atomic deposition has good uniformity, and has great potential to become nanometric reference material for AFM and scanning electron microscope (SEM) calibration.
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