System and methods for silicon on insulator MEMS pressure sensors are provided. In one embodiment, a method comprises: applying a doping source to a silicon-on-insulator (SOI) silicon wafer having a sensor layer and an insulating layer comprising SiO2 material; doping the silicon wafer with Boron atoms from the doping source while controlling an injection energy of the doping to achieve a top-heavy ion penetration profile; and applying a heat source to diffuse the Boron atoms throughout the sensor layer of the SOI silicon wafer.