Space-Saving Wearables: Silicon Trench Capacitors Revolutionize Design

Rohm Introduces Silicon Capacitors for Miniaturized Electronics

Rohm, a leading semiconductor manufacturer, has announced the development of its first silicon capacitors. The new BTD1RVFL series offers a compact size and high performance, making it suitable for a wide range of applications in the electronics industry.

The BTD1RVFL series features a size of 400 x 200 x 185μm (01005, 0402 metric), which is significantly smaller than the general 0201 (0603 metric) products. This reduction in size allows for a mounting area that is approximately 55% smaller, measuring just 0.08mm2. Additionally, these capacitors are equipped with a built-in transient voltage suppressor protection element, ensuring high electrostatic discharge (ESD) resistance.

With a voltage rating of 3.6V, the BTD1RVFL series offers reliable performance. The internal bi-directional TVS (transient voltage suppressor) breaks down between 8.2 and 9.2V, providing effective protection against voltage spikes and transients.

One of the key features of the BTD1RVFL series is the use of trenching technology, which allows for increased capacitance per unit area. Unlike traditional ceramic capacitors, these silicon capacitors do not follow the three-character temperature coefficient labeling system. Instead, they operate over a wide temperature range of -55 to +150°C, with a temperature coefficient of ±250ppm/°C. The capacitance tolerance is ±15%, ensuring accurate and reliable performance.

Rohm's miniaturization technology enables precise processing in 1µm increments, eliminating chipping during external formation and improving dimensional tolerances within ±10µm. This small variation in product size allows for mounting with a narrower distance between adjacent components. Furthermore, the backside electrode used for bonding to the substrate has been expanded to the periphery of the package, enhancing mounting strength. The total pad area for bonding measures approximately 0.032mm2.

The BTD1RVFL series is just the beginning for Rohm's silicon capacitor lineup. Two parts are currently available, with five more under development. These capacitors are expected to find applications in smartphones and wearables, where space is limited and high performance is crucial.

Rohm has plans to introduce a second series next year, focusing on improved high-frequency characteristics for RF applications. This series will offer lower equivalent series resistance (ESR) and lower loss, making it ideal for wireless communication devices. In 2026, Rohm aims to release a third generation of silicon capacitors with higher voltage ratings, targeting industrial and automotive applications.