CMOS Implementation of POSFET Tactile Sensing Arrays with on Chip Readout

Abstract

This work presents a new design of the novel POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) devices based tactile sensing chips - currently under fabrication. The tactile sensing chip, primarily developed for the robotic applications, consists of 4x4 POSFET touch sensing devices or taxels. In addition to the touch sensing devices, the new chip includes electronic circuitry comprising of multiplexors, current mirrors and buffers. The POSFET touch sensing devices are obtained by spin coating piezoelectric polymer P(VDF-TrFE), poly(vinylidene fluoride - trifluoroethylene), film on the gate area of MOS (Metal Oxide Semiconductor) devices and polarizing the film in situ. To detect contact events, the taxels utilize the contact forces induced change in the polarization level (and hence change in the induced channel current) of piezoelectric polymer. Both, individual taxels and the array are designed to match spatio-temporal performance of the human fingertips.