| Structural |
|---|
|
Polysilicon |
Mechanical structures (beams, springs); LPCVD from SiH₄ |
|
SiO₂ |
Insulation/mechanical layer; thermal oxidation or PECVD |
|
SU‑8 |
High‑aspect‑ratio photoresist; spin‑coat + UV lithography |
| Conductive |
|---|
|
Aluminum (Al) |
Interconnects; sputtering or evaporation |
|
Gold (Au) |
Electrodes, bonding pads; evaporation or sputtering |
|
Titanium (Ti) / Chromium (Cr) |
Adhesion/barrier layers; sputtering or evaporation |
|
Platinum (Pt) |
Sensors/electrodes; sputtering or evaporation |
| Piezoelectric |
|---|
|
PZT |
Actuation/sensing; sol‑gel spin‑coat or sputtering |
|
AlN |
CMOS‑compatible; reactive sputtering |
|
ZnO |
Piezo layer; sputtering or CVD |
| Thermal & Resistive |
|---|
|
Poly‑Si |
Heaters/thermistors; LPCVD |
|
Platinum (Pt) |
RTDs; sputtering or evaporation |
|
NiCr |
Thin‑film resistors; sputtering or evaporation |
| Sacrificial |
|---|
|
SiO₂ |
Common sacrificial layer; thermal oxidation or PECVD |
|
Photoresist |
Patternable support; spin‑coat |
|
Polyimide |
Flexible sacrificial; spin‑coat + bake |
| Substrates |
|---|
|
Silicon |
Standard; <100> or <111> orientation |
|
SOI |
Buried oxide for release; device layer over BOX |
|
Glass / Quartz |
Optical/RF; anodic bonding (glass) or stable resonance (quartz) |
|
Polymers |
Flexible MEMS; e.g. Kapton, PDMS |