Our work presents embedded high-density oxide-nitride-oxide (ONO) trench capacitors for power supply decoupling in the next generation of smart catheters. These millimeter-scale smart catheters are using a novel integration platform, Flex-to-Rigid (F2R). In the F2R platform, various functional modules are fabricated or assembled on thin silicon islands. They are connected by flexible interconnects and can be folded into arbitrary shapes to facilitate small form-factor integration. Trench decoupling capacitors have the advantage of being integrated into the thin silicon islands of F2R to reduce the parasitic inductances and space consumption. Additionally, their small surface openings can be closed by layer deposition to enable follow-up processes on the closed-up surface. For demonstration, high aspect ratio (1.1:25 and 1.2:30) ONO trench capacitors with total areas of 300x300 µm 2 and 1000x1000 µm 2 are fabricated on planar wafers, and a 700 nm and a 1 µm thick plasma-enhanced chemical vapor deposition (PECVD) SiO2 layers are deposited to test the trench closing process. The F2R compatible ONO trench capacitors have capacitance densities of 6.17 nF/mm 2 and 10.12 nF/mm 2 , combined with breakdown voltages ranging from 28 to 30 V.@en

Vagus nerve stimulators currently on the market can treat epilepsy and depression. Recent clinical trials show the potential for vagus nerve stimulation (VNS) to treat epilepsy, autoimmune disease, and traumatic brain injury. As we explore the benefits of VNS, it is expected that more possibilities for a new treatment will emerge in the future. However, existing VNS relies on electrical stimulation, whose limited selectivity (due to its poor spatial resolution) does not allow for any control over which therapeutic effect to induce. We hypothesize that by localizing the stimulation to fascicular level within the vagus nerve with focused ultrasound (US), it is possible to induce selective therapeutic effects with less side effects. A geometrically curve US transducer array that is small enough to wrap around the vagus nerve was fabricated. An experiment was conducted in water, with 48 US elements curved in a 1 mm radius and excited at 15 MHz to test the focusing capabilities of the device. The results show that the geometrical curvature focused the US to an area with a width and height of 110 μm and 550 μm. This will be equivalent to only 2.1% of the cross section of the vagus nerve, showing the potential of focused US to stimulate individual neuronal fibers within the vagus nerve selectively.@en