Sidewall epitaxial piezoresistor process for in-plane sensing applications

We report, a novel, selective epitaxial fabrication method to form piezoresistors on the sidewalls of microstructures for in-plane sensing applications. We have fabricated and characterized cantilevered force sensors with lateral piezoresistors. Their sensitivity was found to be 2-7 times more sensitive than most ion-implanted cantilevers we have made with equivalent dopant concentration. In addition, we have characterized noise and electrical characteristics and the effect of trench dimension on deposition rate.