MICRO • INTERDIGITATED

Two combs, interleaved

┃┃┃ ⇄ ┃┃┃

The classic in-plane layout: a positive comb and a negative comb whose fingers interleave. Every finger faces a neighbor of the opposite polarity, so ions only cross one small gap.

Design knobs Finger width, gap, length, number of fingers, and height

MICRO • BEYOND STRAIGHT COMBS

Patterns with more edge

Concentric rings

Round layouts that suit circular chips and coin-like devices

Spirals

Two intertwined spiral arms packed into a small round footprint

Serpentine

Winding, meandering fingers that can also flex

Fractal-style

Space-filling curves explored to pack long facing edges into little area

The goal is more electrode-to-electrode edge per footprint, where ions have short paths.

MICRO • GOING 3D

Grow upward, not outward

Tall walls High-aspect-ratio fingers add sidewall area

Pillar arrays Forests of posts or rods with a lot of surface

Etched trenches Deep wells or trenches carved into silicon, then coated

Porous scaffolds Foams and sponges as 3D skeletons for active material

The footprint stays fixed while the active area grows, but deep electrodes can starve for ions if they get too tall or dense.

UNIT 15 STUDY COMPLETE

🧩

Ready for the Fab Challenge?

You've covered combs, spirals, and 3D fingers for on-chip energy storage.