An unreleased mm-wave Resonant Body Transistor

In this work, we present the first fully unreleased Micro-Electro-Mechanical (MEM) resonator. The 1st harmonic longitudinal resonance of a silicon FinFET fully clad in SiO
₂
is demonstrated. The device exhibits two resonances at 39 and 41 GHz, corresponding well with simulation results. The quality factor (Q) of 129 at 39 GHz is ~4× lower than that of its released counterpart. Methods to improve Q and reduce spurious modes are introduced. This first demonstration of unreleased resonators in a hybrid MEMS-CMOS technology can provide RF and microwave CMOS circuit designers with active high-Q devices monolithically integrated in Front-End-of-Line (FEOL) processing without the need for post-processing or special packaging.