CRYSTAL GROWING DEVICE WITH MOLECULAR BEAM AND CRYSTAL GROWTH USING THE SAME DEVICE

摘要

PURPOSE:To efficiently carry out stable epitaxial growth by equipping plural turbo-molecular pumps to evacuate a crystal growing chamber in vacuum in series and providing the connecting part between the pumps with gas inlet mechanism to control flow rate. CONSTITUTION:Turbo-molecular pumps 12A and 12B are connected in series in a crystal growing chamber 1 and an oil trap 13 and a rotary pump 14 are coupled with the delivery side. The connecting part of the pumps 12A (first stage) and 12B (first stage) is equipped through a stopper valve 16, a mass flow controller 18 and a stopper valve 17 with a high-purity gas bomb 15. In the constitution, the crystal growing chamber 1 is evacuated by operating the pumps 12A, 12B and 14, a given flow rate of nitrogen gas from the bump 15 is fed to the crystal growing chamber 1 to carry out baking. After the baking is stopped and the chamber is returned to room temperature, a liquid nitrogen shroud 6 is charged with liquid nitrogen and crystal is grown on a substrate 2 by conventional procedure. Consequently, contamination by the rotary pump 14 is prevented while maintaining exhaust ability of large volume to efficiently give high-quality epitaxial growth crystal layer.