Single Crystal and Polycrystalline 3C-SiC for MEMS Applications

Abstract

Cantilever resonators have been fabricated from two types of materials, single crystal and polycrystalline 3C-SiC films. The films have been grown in a hot-wall chemical vapor deposition reactor on 100 mm diameter p-type boron-doped (100) Si wafer without rotation of the wafer. The crystal structure of the films have been accessed with X-ray diffraction. The cantilever devices have been fabricated using a one-step etch and release process; the beam length has been varied between 50 and 200 µm. Resonant frequencies in the range 110 KHz – 1.5 MHz and 50 – 750 KHz have been obtained for single crystal and polycrystalline SiC devices, respectively. Furthermore, the experimental resonance frequencies have been used to calculate the Young’s Modulus E for the two different types of SiC. The single crystal SiC, possessing a very high Young’s Modulus (446 GPa), should be an optimal material for RF-MEMS applications.