How to avoid plastic deformation in GaAs wafers during molecular beam epitaxial growth

Plastic deformation in two-inch diameter GaAs wafers resulted from standard thermal treatments which accompanied epitaxial growth in molecular beam ep itaxy (MBE) machines of three different makes. Synchrotron based X-ray tran smission topography was used to distinguish between thermal treatment induc ed dislocation bundles and misfit dislocations. Eradication of the wafer sl ip related dislocation bundles has been achieved by modifications to the sa mple holder of a user built MBE machine. These modifications are discussed, the extent of the problem is briefly outlined, and an extrapolation of the susceptibility of GaAs wafers of higher diameters to this type of plastic deformation is given.