We have micro-fabricated a novel n-channel field effect transistor (FET) cantilever that is proposed to sense surface potential profile in nanometer scale. Conventional techniques used in surface and bulk micro-electromechanical system (MEMS) and combined complementary metal oxide semiconductor (CMOS) process have been employed to make a novel n-channel FET cantilever made of silicon on insulator (SOI) wafers. The cantilevers with various beam lengths, width, and thickness have been fabricated and their resonance frequencies were measured. Thermal annealing after high-dose ion implantation controlled the channel length between the source and the drain. This cantilever resembles nchannel metal oxide semiconductor FET (n-MOSFET) without a gate electrode. If a biased or charged sample is positioned closed to the cantilever, it works as the gate electrode. The device characteristics of the novel FET cantilevers were similar to the conventional n-MOSFET.