TY - JOUR

T1 - Estimation of residual stresses in single crystal sapphire wafers through eigenmode analysis

AU - Gruber, Manuel

AU - Kreith, Josef

AU - Lohrasbi, S.

AU - Bermejo, Raul

AU - Supancic, Peter Hans

N1 - Publisher Copyright: © 2025

PY - 2025/1/9

Y1 - 2025/1/9

N2 - Methods for growing high-quality single-crystalline sapphire boules are energy-intensive due to the material's high melting point. Residual stresses and stress gradients due to temperature gradients and/or growth direction may develop during manufacturing process. An approach is developed based on acoustic measurements to resolve residual stresses in sapphire wafers. Experimental analyses reveal distinct resonance frequencies depending on the processing conditions and wafer's original position within the boule. Natural frequencies are calculated for different modes using a finite element model on samples with and without residual stresses. Shifts in resonance frequency between wafers can be explained by the presence of residual stresses of few MPa, which may not be resolved with conventional residual stress measurement methods. The proposed acoustic method demonstrates precision and repeatability in discerning subtle differences even between wafers from a single boule in a non-destructive manner, offering potential for optimization of single-crystalline sapphire wafer production processes.

AB - Methods for growing high-quality single-crystalline sapphire boules are energy-intensive due to the material's high melting point. Residual stresses and stress gradients due to temperature gradients and/or growth direction may develop during manufacturing process. An approach is developed based on acoustic measurements to resolve residual stresses in sapphire wafers. Experimental analyses reveal distinct resonance frequencies depending on the processing conditions and wafer's original position within the boule. Natural frequencies are calculated for different modes using a finite element model on samples with and without residual stresses. Shifts in resonance frequency between wafers can be explained by the presence of residual stresses of few MPa, which may not be resolved with conventional residual stress measurement methods. The proposed acoustic method demonstrates precision and repeatability in discerning subtle differences even between wafers from a single boule in a non-destructive manner, offering potential for optimization of single-crystalline sapphire wafer production processes.

KW - Acoustic methods

KW - Elastic behavior

KW - Finite element analyses

KW - Residual stress

KW - Single crystal wafer

UR - http://www.scopus.com/inward/record.url?scp=85214321880&partnerID=8YFLogxK

U2 - 10.1016/j.scriptamat.2025.116538

DO - 10.1016/j.scriptamat.2025.116538

M3 - Article

AN - SCOPUS:85214321880

VL - 259.2025

JO - Scripta Materialia

JF - Scripta Materialia

SN - 1359-6462

IS - 1 April

M1 - 116538

ER -