The influence of the scatter of heat flux at the m/c interface on the frequency of appearance of poly body and twin defects during 6″ semi-insulating GaAs crystal growth by the VGF method (original) (raw)

The challenge of increasing and maintaining a high yield for 6 00 GaAs crystal growth is of utmost importance for meeting the price requirements dictated by today's requirements for semi-insulating GaAs substrates. For maintaining a low dislocation density in the grown ingots, the growth process time is typically long and, sometimes, the final ingots may exhibit twins and poly-crystalline formation. These defects may occur at the beginning of the cylindrical part of the ingot, or even at the conical part of pBN crucible so the whole ingot is rejected. On the other hand, these defects may appear further away from the seed and the location of the onset of these defects will determine the extent of the useful (production worthy) crystal length, also known as ''yield''. The reasons for the onset of these defects are, however, not fully understood [M.