Length-extension LGS microresonators for FM-AFM: Microfabrication and shear effects sensitivity

This paper investigates some properties of vibrating beam resonators in length extensional mode and mainly the energy loss by coupling between the beam and the frame of the device. The resonators were designed and built using an alternative material of quartz, the langasite (LGS), which has some interesting piezoelectric and thermal properties. The process of microfabrication is based on the anisotropic chemical etching whose main advantage is that it is a low cost process. Several characterizations of the devices were performed to control first the shape of the cantilever and the size of the tip at its end. Second, electrical and optical measurements were conducted to obtain the resonant frequency for extensional mode and to detect the shear mode of vibration. The results were compared with the theoretical ones which have been obtained using a FEM simulator. In this paper, we proved the interest of such devices to obtain probes with high performances for FM-AFM microscopy.