| 摘要 |
PURPOSE:To obtain easily a p type GaAs single crystal with low dislocation density by the three-temp. zone type horizontal Bridgman method by selecting conditions during growth and by double-doping GaAs with Zn and S. CONSTITUTION:The three temp. zone type horizontal Bridgman method is applied, and a GaAs polycrystal is doped with 1-4X10<18>cm<-3> S and 2X10<18>-10X 10<19>cm<-3> Zn. Conditions during growth are selected so as to adjust the temp. gradient of the whole region between high and intermediate temp. zones to 1- 2 deg.C/cm, the growing rate to 1-5mm./hr, and the vertical temp. gradient in the vicinity of the growing interface to 1-2 deg.C/cm. Thus, a p type GaAs single crystal with low dislocation density is obtd. The crystal contains S and Zn, and the concn. of S is by >=1X10<18>cm<-3> lower than the concn. of Zn. The crystal has p type electric conductivity due to 1X10<18>-9X10<19>cm<-3> concn. of carriers and <=1,000cm<-2> average dislocation density. |
