| 摘要 |
PURPOSE:To make it possible to monitor the strength of individual molecular beam simultaneously during the growth of crystals, by impressing high voltage between the vacuum evaporation material of a molecular beam source and a base plate and monitoring ionic current generated by partially ionized molecular beams. CONSTITUTION:At the growth of each, molecular beams of arsenic is directed to a GaAs base plate 1, which has been heated up to about 600 deg.C, from a source of arsenic molecular beam 13. Further Ga melt 9 in a BN crucible 8 is heated to 950-1050 deg.C to direct the Ga molecular beams to the GaAs base plate 1, causing the crystal to grow. When DC voltage of 950 volt is impressed from outside a vacuum container 20 between a Ta wire 6 and an electrode 12, a part of Ga atoms evaporated from the Ga melt 9 is ionized and reach the GaAs base plate 1, where ionic current is observed. Since the growth rate of crystal is proportional to ionic current, monitoring of the actual crystal growth, i.e. the strength of beam during growth is possible based on the actually measured values of ionic current. |
