Discussion and analysis of Au/a-Si contact resistance in MEMS/NEMS devices

In this work, reliable electric interconnection for MEMS/NEMS devices was realized by Au/a-Si (amorphous Si) and Au/c-Si (single-crystal Si) eutectic reaction in anodic wafer bonding process. We measured different resistances of different bonding areas under different bonding temperature. When bonding temperature is under 370 °C, the resistance of the different areas (from 200 μm² to 1000 μm²) fluctuate within a narrow range and more than 80 % of the resistance is less than 10 ohm. Compared with Au/c-Si contact, Au/a-Si contact is more reliable. When bonding temperature is above 370 °C, the resistance is related to the contact area and the discrete nature of the resistance is relatively large. According to statistics, more than 50 % of the resistance is above 100 ohm.