Micro-electromechanical (MEM) laterally vibrating square resonators and beams, fabricated via a prototyping technology combining FIB-micromachined gaps with conventional UV lithography in 1.35 mu m thick SOI are presented. Resonators with both capacitive and MOSFET detection and gaps of similar to 100 nm are demonstrated. Resonance frequencies of 32 MHz and 13 MHz were measured for squares and beams, respectively. The square shaped resonators have Q-factors in the order of 4000. This paper reports on a vibrating body MOS transistor active detection scheme integrated in a MEMS fabrication process to improve the signal read out.