Crystal quality of InGaAs epitaxial layer on 3-inch diameter VCZ/LEC InP(Fe) substrates

Crystal quality of InGaAs epitaxial layers grown by MOCVD on a 3-inch diameter Fe-doped VCZ/LEC InP substrates have been studied by double crystal X-ray diffraction measurements. The crystallographic property of the InP substrates reflected on the InGaAs layers. The average full width at half maximum (FWHM) of X-ray rocking curves of the InGaAs layer on the VCZ-grown InP substrate was narrower than that on the LEC-grown InP substrate. X-ray topographies of the InGaAs layer on the VCZ-grown InP substrate showed less lattice orientation variation than that on the LEC-grown InP substrate. Dark currents of p-i-n photodiodes fabricated on the epitaxial wafers were also studied. The average dark current on the VCZ-grown InP substrate was lower than that on the LEC-grown InP substrate. The standard deviation of dark currents on the VGZ-grown InP substrate was also smaller than that on the LEC-grown InP substrate. Therefore, InGaAs epitaxial layers on 3-inch diameter VCZ-grown InP substrates have superior quality from crystallographic and device characteristics point of view