Towards bendable piezoelectric oxide semiconductor field effect transistor based touch sensor

This paper reports recent advances related to the piezoelectric oxide semiconductor field effect transistor (POS-FET) based touch sensing system research. We reported in past, the POSFETs with basic electronics realized on planar silicon substrates using CMOS technology. However, the planar POSFETs could not be used on 3D or curved surfaces such as the fingertip of a robot. To overcome this challenge we are now investigating the ultra-thin-chip approach for obtaining bendable POSFETs tactile sensing array. This paper presents this approach towards obtaining bendable POSFETs. Furthermore, for the first time the theoretical behavior of POSFETs devices are examined by combining the piezoelectric capacitor model proposed and the physics of underlying metal-oxide-semiconductor (MOS) FETs in the linear and saturation regions. The device characteristic equations are simulated using MATLAB and comparable matching is achieved with the experimental measurements. The model result gives a unique insight into geometrical and material properties of piezoelectric polymer on the electrical properties of transistor for flexible electronics applications. Using this model, the Spice simulation of POSFET device in a single-ended op-amp configuration, and the effect of chip thickness on deflection are presented.