HEAT TREATMENT OF GALLIUM ARSENIDE SINGLE CRYSTAL

摘要

PURPOSE:To uniformize the electrical characteristics in the axial direction of the In-doped dislocation-tree single crystal produced by a liquid sealing pulling up method by subjecting said single crystal to two stages of heating treatments at the specified temps. after the end of the crystal growth thereof. CONSTITUTION:The In-doped dislocation-tree single crystal of gallium arsenide of a low carbon concn. (<=2X10<15>cm<-3>) produced by the liquid sealing pulling up method is subjected continuously to the two stages of the heating treatment; the 1st and 2nd heat treatments in the pulling up stage, more preferably after the end of the pulling up stage. The treatment at 1050-1200 deg.C is adopted as the 1st-stage heat treatment and 750-950 deg.C as the 2nd-stage heat treatment. The heat treatment time for the above-mentioned two stages is specified for >=30minutes respectively and the cooling rate from the 1st-stage heat treatment temp. to the 2nd-stage heat treatment is specified to 10-200 deg.C/min. The crystal heat hysteresis can be initialized by the above-mentioned 1st-stage heat treatment in such a manner that the characteristics over the entire area of the crystal ingot are approximated extremely to the characteristics possessed by the state right after the crystal solidification. The stabilization of the electrical characteristics and semi-insulation are attained by the 2nd-stage heat treatment.