Non-axisymmetric flexural vibrations of free-edge circular silicon wafers

Abstract

Non-axisymmetric flexural vibrations of circular silicon (111) wafers are investigated. The modes with azimuthal index 2 ⩽ k ⩽ 30 are electrostatically excited and monitored by a capacitive sensor. The splitting of the mode frequencies associated with imperfection of the wafer is observed. The measured loss factors for the modes with 6 ≲ k ≲ 26 are close to those calculated according to the thermoelastic damping theory, while clamping losses likely dominate for k ≲ 6 , and surface losses at the level of inverse Q -factor Q − 1 ≈ 4 × 10 − 6 prevail for the modes with large k . The modes demonstrate nonlinear behavior of mainly geometrical origin at large amplitudes. • Non-axisymmetric flexural vibrations of circular silicon wafers are investigated. • Vibration modes with azimuthal index 2 < k < 30 and zero radial index are explored. • Measured loss factors are close to calculated thermoelastic loss for most of modes. • The surface losses likely dominate for the modes with large angular index. • Nonlinearity of the modes is also explored.