A Novel Fabrication Platform for Acceleration Sensor Switch with Top Contacts

This report describes a novel microfabrication platform to realize an acceleration sensor switch with top contacts in the out-of-plane direction. The platform utilizes conventional micromachining processes on 8″ silicon wafers. The acceleration switch top contacts are realized with a composite structure of an Al bridge spring, hardened at the contact locations with TiN, in order to provide robustness while allowing some compliance for a prolonged contact time and minimal bouncing effects. The silicon proof mass is also hardened at the contact locations with TiN. The fabricated acceleration sensor switch is demonstrated to have a threshold of under 40g, which is well-suited for IoT applications.