Crystal anomaly at the center of S doped InP wafers grown by the LEC method

Crystal quality of 2" /spl phi/ S doped InP wafers grown by the conventional liquid encapsulated Czochralski (LEC) method was studied by the photoluminescence (PL) mapping technique and the double crystal X-ray diffraction method. Crystal anomaly was found at the center of the wafer. The dark current distribution map of the InGaAs/InP PIN-photodiodes fabricated on the S doped InP substrate revealed that this crystal anomaly at the center increased the dark currents of the photodiodes.