CONTROL OF EPITAXIAL RELATION OF GAAS FILM ON FLUORIDE/SI(111) STRUCTURE

The X-ray diffraction measurements have revealed that the type B region, whose crystallographic orientation is rotated 180-degrees about the surface normal with respect to the CaF2 film (rotational twin), partially exists in a GaAs film on CaF2(111). It is found that the fraction of the type B region increases as the GaAs growth temperature increases for good crystallinity in GaAs films. A decrease in temperature at the initial stage of growth followed by an increase in temperature, i.e., the two-step growth method, is found to be very effective for suppressing the generation of the rotational twins at the GaAs/CaF2 interface so as to grow high-quality GaAs on CaF2/Si(111).