MBE device and method of its operation

摘要

The molecular beam epitaxy device for reactively depositing group III nitride compound semiconductor, comprises a vacuum chamber (10) having a molecular beam source (11) and an injector (12), which is arranged for injecting ammonia into the vacuum chamber, a first cooling trap device (20), which comprises a first cooling trap for condensing surplus ammonia and a second cooling trap, a pumping device (30) with a pump, which is arranged for evacuating the vacuum chamber, and a blocking device, with which the first cooling trap device is separatable from the vacuum chamber. The molecular beam epitaxy device for reactively depositing group III nitride compound semiconductor, comprises a vacuum chamber (10) having a molecular beam source (11) and an injector (12), which is arranged for injecting ammonia into the vacuum chamber, a first cooling trap device (20), which comprises a first cooling trap for condensing surplus ammonia and a second cooling trap, a pumping device (30) with a pump, which is arranged for evacuating the vacuum chamber, a blocking device, with which the first cooling trap device is separatable from the vacuum chamber, and a second cooling trap device (50) arranged for condensing residual gas in the vacuum chamber. The first and second cooling traps are arranged in separate vacuum connections between the vacuum chamber and the pumping device. The blocking device comprises two blocking elements, which are arranged between the vacuum chamber and the cooling traps. When one of the cooling traps is separated from the vacuum chamber by the blocking device, the other cooling trap is connected with the vacuum chamber. The cooling trap separated from the vacuum chamber is arranged for releasing the condensed ammonia. The cooling trap comprises a tubular baffle, which is arranged in the vacuum connection between the vacuum chamber and the pump, and a cooling shield, which is arranged in an additional vacuum chamber. The blocking element is arranged between the vacuum chamber and the additional vacuum chamber. The cooling trap is separately evacuatable from the vacuum chamber with a fore-pump of the pumping device and is connected with the fore-pump over a blockable bridging line. The second cooling trap device comprises a cooling shield, which is arranged in the vacuum chamber, and is interpreted for an operating temperature, in which ammonia remains in gaseous state under vacuum conditions and condenses the residual gas in the vacuum chamber. An independent claim is included for a method for operating a molecular beam epitaxy device.