High Sensitivity Magnetic Field Sensors Based on Nano-Polysilicon Thin-Film Transistors

A high-sensitivity magnetic field sensor based on the nano-polysilicon thin film transistors is proposed to adopt the nano-polysilicon thin films and the nano-polysilicon/single silicon heterojunction interfaces as the sensing layers. By using CMOS technology, the fabrication of the nano-polysilicon thin film transistors with Hall probes can be achieved on the 〈100〉 high resistivity single silicon substrates, in which the thicknesses of the nano-polysilicon thin films are 120 nm and the length width ratio of the channel is 320 μm/80 μm. When VDS = 5.0 V, the magnetic sensitivity and linearity is 264 mV/T and 0.23%f.s. (full scale), respectively. The experimental results show that the magnetic sensors based on nano-polysilicon thin film transistors with Hall probes exhibit high sensitivity