Residual stress distribution and flatness of dislocation-free Te-GaSb (100) substrate

Abstract

Raman spectroscopy has been used to evaluate residual stress distribution across GaSb single crystal wafers with different Te doping concentrations grown by liquid encapsulated Czochralski (LEC) method. Undoped GaSb wafers grown by LEC and vertical temperature gradient freezing method were used as reference wafers for comparison analysis. The residual stress increases but its distribution uniformity improves in LEC-GaSb wafers with the concentration of Te dopant increasing. Moreover, annealing at temperature 650 °C can effectively increase its distribution uniformity and results in an improvement of the flatness. The results also suggest that the flatness of GaSb wafers is better when Te doping concentration is controlled within a certain range.