Review: Semiconductor Piezoresistance for Microsystems

TLDR

Piezoresistive sensors were among the earliest micromachined silicon devices, and the drive for smaller, cheaper, higher‑performance sensors spurred micromachining technology; since the 1954 discovery of stress effects in doped silicon and germanium, microscale piezoresistive strain gauges, pressure sensors, accelerometers, and cantilever force/displacement sensors have been extensively reported, with many commercial successes. This review surveys the history, physics, and fabrication techniques of piezoresistance. The authors examine electrical noise in piezoresistors, present device examples, outline design considerations, and explore alternative materials. The paper offers a comprehensive overview of integrated piezoresistor technology, covering physics, process and material selection, and design guidance useful to researchers and device engineers.

Abstract

Piezoresistive sensors are among the earliest micromachined silicon devices. The need for smaller, less expensive, higher performance sensors helped drive early micromachining technology, a precursor to microsystems or microelectromechanical systems (MEMS). The effect of stress on doped silicon and germanium has been known since the work of Smith at Bell Laboratories in 1954. Since then, researchers have extensively reported on microscale, piezoresistive strain gauges, pressure sensors, accelerometers, and cantilever force/displacement sensors, including many commercially successful devices. In this paper, we review the history of piezoresistance, its physics and related fabrication techniques. We also discuss electrical noise in piezoresistors, device examples and design considerations, and alternative materials. This paper provides a comprehensive overview of integrated piezoresistor technology with an introduction to the physics of piezoresistivity, process and material selection and design guidance useful to researchers and device engineers.