Surface-micromachined flexible polysilicon sensor array

A flexible polysilicon strain gauge array has been realized using surface micromachining with SiO₂ sacrificial layer. The realized sensor array is mechanically flexible, which can be attached on nonplanar surfaces. To realize the flexible strain gauge, a new packaging scheme using polysilicon/oxide based surface-micromachining was developed. The proposed packaging scheme completes the strain sensors and the circuit board on a single process, which eliminates additional assembly and alignment problems. The measured gauge factor shows that it is more sensitive than metal strain gauge. Unlike a single-crystal silicon strain gauge, the proposed polysilicon gauge does not have any limitations in the direction of strain.