A noble suspended type thin film resonator (STFR) using the SOI technology

The fabrication and characteristics of suspended type thin film resonators (STFRs) using surface micromachining of the SOI technology, have been studied. The size of the active part of STFRs is 160 mum x 160 mum. For the piezoelectric AlN thin film, the following etch rate was observed 200 nm min(-1) in 0.6 wt.% TMAH. The thickness of the piezoelectric AlN film for the STFR is 2 mum. Cr thin film is used as the top and bottom electrode. This device is free-standing and has a resonant frequency of 1.65 GHz for the 2 mum AlN thin film, a K-eff(2) of 2.4%, Q(s) of 91.7, Q(p) of 87.7. (C) 2001 Elsevier Science B.V. All rights reserved.