Table 1.
Summarized design parameters of the MEMS sensing element.
| Parameter | Symbol | Value |
|---|---|---|
| Chip size | 3.4 mm × 2.0 mm | |
| Device layer thickness of (111) SOI wafer | t0 | 65 μm |
| Torsional spring | ||
| Width | wspring | 4 μm |
| Length | lspring | 150 μm |
| Thickness | t | 25 μm (±2 μm) |
| Number of springs | nspring | 2 |
| Torsion angle at 1 g input (at t = 25 μm) | θ | 2.59 × 10−4 rad |
| Comb finger | ||
| Width | w | 5 μm |
| Length | lcomb | 210 μm |
| Thickness | t | 25 μm (±2 μm) |
| Comb overlap length | l | 200 μm |
| Vertical gap length | g | 13 μm (±1 μm) |
| Gap between comb finger | d | 4 μm |
| Effective distance from center to comb finger | l’ | 8.13 × 10−4 m |
| Number of combs | n | 254 |
| MEMS structure | ||
| Area size | - | 9.72 × 10−6 m2 |
| Area of asymmetric part | - | 2.74 × 10−7 m2 |
| Center of mass | xcm | 5.58 × 10−4 m |
| Thickness | t | 25 μm (±2 μm) |
| Device length | a | 2.53 mm |
| Device width | b | 1.388 mm |
| 1st mode natural frequency (at t = 25 μm) | ωn | 598 Hz |