| 摘要 |
PURPOSE:To prevent contamination of a crystal with Si from a quartz boat with a titled growing method usig the Bridgeman's method of horizontal two-temp. by specifying the construction in the rear part of the ampoule on the high temp. side of a reaction tube and the temp. region of furnace heaters. CONSTITUTION:A temp. gradient part L2 kept at about <=1,250 deg.C and a high-temp. region L3 where a GaAs melt 44 is held are formed by a heater 41. The respective regions are made loger than the length L1 of a quartz boat 43. On the other hand a low- temp. region L4 where metallic As is kept at about 610 deg.C is formed by a heater 42. Quartz ampoules 40, 51 on high- and low-temp. sides are connected by a quartz tube 53. Partition chambers which are disposed with quartz tubes 46 fused at the central part to plural partition plates 45 of a prescribed interval are disposed above and below and in which a gas resistor 47 is packed according to need are provided in the front and rear parts. The melt 44 is seeded 48 and the reaction tube is moved leftward relatively with the furnace to move the melt 44 to the gradient part L2 set at 1-10 deg.C/cm thereby moving a solid-liquid boundary 50 and growing a single crystal. The temp. at the left end 49 of the ampoule 40 is decreased by the part L2 in this stage, by which the reaction of As and Ga2O is accelerated but the temp. gradient is gentle and therefore the activity of Si in GaAs does not increase so much. |
