Gallium-Doped Piezoresistive Sensor With Optimized Focused Ion Beam Implantation

In this paper, we present the results of gallium implantation/doping in silicon using focused ion beam (FIB) to realize gallium (Ga) doped piezoresistive pressure sensor. We have performed optimization of various FIB parameters and demonstrated that with this approach, a gauge factors of about 100 and a sheet resistance of 1-2 kQ/square can be achieved using optimized FIB doses in range of 5×10¹⁷-8×10¹⁸ ion/m². The results open a novel and simple way of fabricating piezoresistors especially on nanoscale structures where lithography can be challenging.