Structural defects of GaN deposited on (111) Si with Gd2O3-related buffer layers

Abstract

The structural defects of GaN deposited on (111) Si with Gd2O3-related rare earth oxide buffer layers were investigated using a double-crystal x-ray rocking curve (DCXRC), high resolution transmission electron microscopy (HRTEM). By comparing the DCXRC signals of (11¯02)GaN and (12¯12)GaN asymmetric planes and (0002)GaN symmetric plane, respectively, it was found that most of the threading dislocations (TDs) in GaN of the GaN on (111) Si using Gd2O3 or Er2O3/Gd2O3 buffer layer are type a TDs in nature. Based on the results of DCXRC studies, it is believed that the full-width at half maxima of the DCXRC signals of (11¯02)GaN and (12¯12)GaN asymmetric planes are primarily due to the contributions of the 1/3⟨12¯10⟩GaN components of the Burgers vectors of type a and type c + a TDs on the interplanar spacing distortions of (11¯02)GaN and (12¯12)GaN planes in GaN of the GaN/Er2O3/Gd2O3/(111) Si samples. HRTEM observations also revealed the presence of extrinsic stacking faults and Frankel partial dislocations in GaN of the GaN on the (111) Si sample with Gd2O3 or Er2O3/Gd2O3 buffer layer.