| 摘要 |
PURPOSE: To eliminate oval defect by providing a semiconductor substrate having the 100 face of GaAs or InP as a major surface, for example, growing a group III-V semiconductor material layer on the major surface to form a device in the layer, and performing one or more steps. CONSTITUTION: A Ga ingot is placed in a crucible slightly coated with Al on the inside and then a 100 GaAs wafer is set in an MBE system. After closing the MBE, the chamber is evacuated to discharge gas from shutter, cell and filament. Cell temperature is regulated to provide a GaAs grow rate of 1μm/hr and the wafer is exposed to the flux for GaAs for 5 hours by releasing the shutter. Subsequently, the wafer is cooled and collected. According to the method,αtype oval defect density can be decreased substantially to zero when a crucible coated with Al is employed.
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