Thermoelastic Analysis of Slip Defect Generation on GaAs Wafers

Abstract

In this work we develop the thermoelastic analysis for prediction of slip defect generation on (001) GaAs wafers, by means of the finite element method taking into account the anisotropic structure and slip system of dislocation. The analysis for a completely circular wafer predicts that longer slip defect lines are generated at the wafer edge of θ=π/8+Δ+nπ/2, 3π/8-Δ+nπ/2 (Δ is about 3°) and the prediction well agrees with the result of the wafer heating experiment. This demonstrates that our anisotropic analysis is more accurate than simple isotropic analysis which predicts slip defect generation at the wafer edge of θ=π/8+nπ/4. According to this thermoelastic analysis, we can additionally confirm that longer slip defect lines are more prone to be generated at the <110> orientation flat (OF) edge than at the circular edge. Finally, we suggest the method of preventing slip defect generation.

Investigation of residual dislocations in VGF-grown Si-doped GaAs

“…Due to the thermal expansion the crystal surface is therefore under tangential tensile stress. Comparing the results to the Schmid factor distribution of 601-dislocations will answer the question whether the cross is formed similar to slip lines at the crystal surface [6,26].…”

Solid mechanics and material strength studies on the melt growth of bulk single crystals

“…Except for the crystal growth process, the thermal stress analyses considering the crystal anisotropy contribute to the accurate predictions of the stress and deformation of the multilayered film heterostructures [22,23] and the slip defect generation on GaAs wafers during their device process [24].…”

Types and origin of dislocations in large GaAs and InP bulk crystals with very low dislocation densities

“…this glide system does not experience any stress. It also means that that these dislocations can not be formed similar to slip-lines at the wafer edge [29,30]. This leads to the conclusion that these dislocations are not formed by stress at all as they usually occur under low stress conditions of crystal growth.…”