PREVENTION OF THERMAL DECOMPOSITION OF GROUP III ELEMENT PHOSPHIDE COMPOUND SUBSTRATE FOR GROWTH OF NITROGEN COMPOUND CRYSTAL

摘要

PROBLEM TO BE SOLVED: To prevent the decomposition of a substrate crystal by heating a group III element compound substrate in an ammonium gas atmosphere and subsequently replacing P atoms near to the surface in the substrate by the N atoms of ammonia to protect the surface of the substrate with the produced silicon nitride crystal layer. ;SOLUTION: A group III element phosphide compound substrate 1 is set in a reaction tube 5 comprising quartz. A highly pure inert gas 6 such as hydrogen, argon, helium or nitrogen gas is made to flow in the reaction tube 5 at a proper flow rate. The group III element phosphide compound substrate 1 is heated with a heater such as an electric oven 7 at a temperature sufficiently lower than a temperature causing the thermal decomposition of the substrate 1. The inert gas flowing in the reaction tube 5 is replaced by ammonia gas 2, and the substrate is heated up to a prescribed temperature and then held at the temperature for a prescribed time. During the time, the surface of the group III element phosphide compound substrate 1 is covered with a nitride crystal 3. In order to inhibit the decomposition of the produced nitride crystal, the substrate is held in an ammonia gas atmosphere or in a nitrogen-supplying atmosphere such as 1,1-dimethylhydrazine during high or low temperature.;COPYRIGHT: (C)1999,JPO