Integrated Stress Sensors – Components, Systems and Applications

Abstract:
Piezoresistive stress sensors are the basic components of numerous mechanical microtransducers. They are applied among others in accelerometers, gyroscopes, resonating devices as well as tactile sensor systems. Typically, diffused resistors are used in a Wheatstone bridge configuration limiting the ultimate miniaturization of these systems required for highly localized stress measurements. This paper reviews novel concepts to operate multi-terminal stress sensors capable of providing simultaneous access to two in-plane stress components at the location of an individual sensor. The components are based on diffused resistors and field effect transistors exploiting the piezoresistive effect. Integrated CMOS based systems using these sensors are applied in process monitoring, e.g. wire bonding, and stress measurements in packaged systems.