| 摘要 |
PURPOSE:To improve the degree of vacuum in a growth chamber and to enable high quality crystal growth by using a gas which has a low vapor pressure at near the temperature of liquid nitrogen and is meagerly reactive at the temperature of a substrate as the carrier gas of a raw material. CONSTITUTION:A carrier gas which bubbles and has a low vapor pressure at near the temperature of liquid nitrogen except H2 is used, the load of a vacuum pump is reduced and the degree of vacuum during growth is improved. The wall of a growth chamber during MBE growth is kept at near the temperature (77 K) of the liquid nitrogen, an H2 gas has the vapor pressure of 1 atmospheric pressure or more at 77 K and is not mutually reactive with the surface of the wall of 77 K. If, however, the carrier gas which has a low vapor pressure at near the temperature of the liquid nitrogen except the H2, part or all of the carrier gas is adsorbed on the surface of the wall of the growth chamber, the wall surface itself is made a pump, i.e., the wall surface can be used as a sort of cryogenic pump, actual exhaust speed can be increased and a high quality crystal film can be obtained.
|
