Micromachined polycrystalline diamond hemispherical shell resonators

The hemispherical resonator gyro (HRG) is low loss and high stability, spurring recent interest in micro-scale hemispherical resonators. To achieve mode-matching and high-Q performance in a hemispherical resonator, geometric symmetry in combination with low thermoelastic damping structural material are critical. In this work, we describe the development of millimeter scale 3D hemispherical shell resonators fabricated from polycrystalline diamond, a material with low thermoelastic damping and very high stiffness. The relation between the fourth harmonic (4θ) in a Fourier analysis of the resonator's radius r(θ) and frequency mismatch (Δf) of the 2θ elliptical vibration modes of the shell resonator is demonstrated.

[1]  C.H.J. Fox,et al.  A simple theory for the analysis and correction of frequency splitting in slightly imperfect rings , 1990 .

[2]  F. Ayazi,et al.  3-D micromachined hemispherical shell resonators with integrated capacitive transducers , 2012, 2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS).

[3]  A. Deneuville,et al.  Non-destructive determination of the boron concentration of heavily doped metallic diamond thin films from Raman spectroscopy , 2003 .

[4]  C. Nguyen,et al.  Hot filament CVD conductive microcrystalline diamond for high Q, high acoustic velocity micromechanical resonators , 2011, 2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings.

[5]  Yogesh B. Gianchandani,et al.  3D-soule: A fabrication process for large scale integration and micromachining of spherical structures , 2011, 2011 IEEE 24th International Conference on Micro Electro Mechanical Systems.

[6]  W. L. Wang,et al.  Internal stress and strain in heavily boron-doped diamond films grown by microwave plasma and hot filament chemical vapor deposition , 1996 .

[7]  FREE VIBRATIONS OF ELLIPTICAL RINGS WITH CIRCUMFERENTIALLY VARIABLE THICKNESS , 1999 .

[8]  S. Mcwilliam,et al.  THE IN-PLANE VIBRATION OF THIN RINGS WITH IN-PLANE PROFILE VARIATIONS PART I: GENERAL BACKGROUND AND THEORETICAL FORMULATION , 1999 .

[9]  S. Bhave,et al.  Isotropic etching of 111 SCS for wafer-scale manufacturing of perfectly hemispherical silicon molds , 2011, 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference.

[10]  D. A. Horsley,et al.  Micromachining 3D hemispherical features in silicon via micro-EDM , 2012, 2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS).

[11]  Edward C. Litty,et al.  Hemispherical Resonator Gyro: an IRU for Cassini , 1996, Optics & Photonics.

[12]  Liwei Lin,et al.  Microcrystalline diamond micromechanical resonators with quality factor limited by thermoelastic damping , 2013 .

[13]  A M Shkel,et al.  Microscale Glass-Blown Three-Dimensional Spherical Shell Resonators , 2011, Journal of Microelectromechanical Systems.