Graduation Year


Document Type




Degree Granting Department

Mechanical Engineering

Major Professor

Daniel P. Hess, Ph.D.

Committee Member

Glen Besterfield, Ph.D.

Committee Member

Tom Eason, Ph.D.


audible, modes, resonance, photovoltaic, rectangular


This thesis presents audible vibratory mode data obtained by mechanically exciting acoustic modes in mc-Si wafers grown by EFG technique with various levels and distributions of residual stress. Stress maps obtained using scanning infrared polariscopy are presented, illustrating the variation of residual stress.

Modal analyses of the wafers are performed using the finite element method and are in remarkably good agreement with the measured frequency response data. The calculated mode shapes were further validated through classic Chladni type patterns.

The vibratory data is found to correlate with the residual stress measurements. The data is fit with both linear and quadratic models with correlation coefficients of 0.8. The results reveal a dependence of wafer audible mode frequencies on residual stress level that may be useful for solar cell mechanical quality control and breakage inspection.