A micromechanical thermal displacement sensor with nanometre resolution

A novel micromachined silicon displacement sensor based on the conduction of heat between two surfaces through the ambient air is described. A displacement resolution of less than 1 nm and a dynamic range of more than 100 mu m was achieved in a 10 kHz bandwidth. To minimize drift, the sensors are operated in pairs, using a differential measurement configuration. The power consumption of these devices is on the order of 10 mW per sensor, and the measured time response is described by a simple exponential with a time constant of approximately 100 mu s.