Evaluation of residual stress in InP and InAs (100) substrates obtained from single crystals grown by LEC and VGF methods

Raman spectroscopy has been used to characterize and compare residual stress distribution across wafers sliced from un-doped InP and InAs single crystals grown by liquid encapsulated Czochralski (LEC) and vertical temperature gradient freezing (VGF) methods, respectively. Both VGF-InP and VGF-InAs wafers exhibit greater residual stress but even distribution across the wafer than their LEC wafers. There is an inverse distribution correlation between the residual stress and the Full width at half maximum (FWHM) of Raman peak for the wafer grown by LEC or VGF method. The flatness results suggest that VGF-grown wafers generally have better flatness parameters but with higher residual stress than LEC-grown wafers.