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LEC法要求有适当的轴向和径向的温度梯度来控制GaAs晶体的直径,但为了降低GaAs单晶的位错密度,又需要降低它们的温度梯度.对大直径GaAs单晶的生长,上述矛盾更为突出.HB法虽然能生长低位错GaAs单晶,但对大直径圆形晶体的生长却无能为力.通常采用VGF(垂直梯度凝固)法来解决大直径和低位错的矛盾.但由于VGF法中要有As源来
The LEC method requires appropriate axial and radial temperature gradients to control the diameter of the GaAs crystals, but in order to reduce the dislocation density of GaAs single crystals, their temperature gradients need to be reduced. For the growth of large diameter GaAs single crystals, The contradiction is more prominent.HB law can grow low dislocation GaAs single crystal, but the growth of large diameter circular crystals are powerless.VGF (vertical gradient solidification) method is usually used to solve the contradiction between large diameter and low dislocation.But the VGF As source to the law