GRAPHITE HEATING ELEMENT FOR PRODUCING DEVICE OF SINGLE CRYSTAL

摘要

PURPOSE:To enhance the service life of a device by heating and melting a raw material in a crucible by a graphite heating element having the specified surface roughness and growing single crystal while pulling-up it. CONSTITUTION:In a Czochralski process, both a raw material such as InP polycrystal and a liquid sealing agent such as B2O3 7 are introduced into a quartz crucible 5 supported by a graphite supporting body 11. The crucible is vacuumized and thereafter inert gas is introduced. Then current is allowed to flow to a graphite heating body 8 having <=0.8mum Rmax surface roughness due to JIS-B-0601 standard. The raw material is melted and InP seed crystal 9 is brought into contact with the melt 6 of the raw material such as InP. InP single crystal 10 is grown while keeping about 7 revolutions/min rotating speed of seed crystal 9, about 15 rotations/min rotating speed of the quartz crucible 5 and about 5mm/hour pulling-up velocity. After the growth of crystal has been completed, crystal is separated from B2O3 7 and cooled at the velocity of about 3 deg.C/min.