4H-Silicon Carbide as an Acoustic Material for MEMS.

Abstract

This paper discusses the potential of 4H-SiC as a superior acoustic material for MEMS, particularly for high-performance resonator and extreme environments applications. Through a comparison of the crystalline structure along with the mechanical, acoustic, electrical, and thermal properties of 4H with respect to other SiC polytypes and silicon, it is shown that 4H-SiC possesses salient properties for MEMS applications, including its transverse isotropy and small phonon scattering dissipation. The utility and implementation of bonded SiC on insulator (4H-SiCOI) substrates as an emerging MEMS technology platform are presented. Additionally, this paper reports on the temperature-dependent mechanical properties of 4H-SiC, including the temperature coefficient of frequency and quality factor for Lame mode resonators. Finally, the 4H-SiC MEMS fabrication including its deep reactive ion etching is discussed. This paper provides valuable insights into the potential of 4H-SiC as a mechano-acoustic material and provides a foundation for future research in the field.