This invention describes a process for depressing the tail dislocation of the gallium phosphide single crystal, comprising the steps of: 1) gradually heating up (at a heating rate of 0.1-0.4 deg.C/min) for 10-30 deg.C 1-2h earlier than the ending of the gallium phosphide single crystal; 2) quitting the follow-up elevation of the pot when the tail floating boat falls down and theres no crystallization at the solid-liquid interface during the crystal growth; 3) pulling the crystal for 1-2h at the previous pulling rate; 4) gradually removing the crystal from the melt and then from the boron oxide, until the crystal is 50mm above the boron oxide, then cooling down to 1000 deg.C and discharging so that the boron oxide foam, followed by cooling down to room temperature. This invention can effectively reduce the interior stress of the single crystal and thus depress the tail dislocation of the single crystal during the growth of the gallium phosphide single crystal. |