JPS6265732A - Mechanism for removing deposit layer for shroud - Google Patents

Abstract

PURPOSE:To remove a deposit layer on the inner wall of a shroud without turning off a vacuum by providing a hammer for hammering the shroud provided in a vacuum vessel from the outside of the vacuum vessel and a bellows for vacuum-sealing the hammer. CONSTITUTION:One end of the hammer 11 is hit by hand, for example, to move the hammer 11 up and down as shown by the arrow A and the shroud 2 is hammered by the other end of the hammer to remove the deposit layer 6 stuck on the inner wall 22 of the shroud 2. Consequently, the deposit layer 6 stuck on the inner wall 22 of the shroud 2 is struck down from the inner wall 22. Since the shroud 2 is usually inclined or directed downward, the deposit layer 6 struck down is dropped from the shroud 2. Besides, an opening 14 for dropping the deposit layer 6, for example, can be provided, as required, at the lower part of the shroud 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for removing a deposited layer attached to the inner wall of a liquid nitrogen shroud in, for example, a molecular beam epitaxy apparatus without breaking the vacuum of a growth chamber housing the shroud. The present invention relates to a shroud deposit layer removal mechanism that allows the removal of shroud layers.

[Conventional technology]

FIG. 3 is a schematic perspective view showing an example of a shroud and its surroundings in a molecular beam epitaxy apparatus. Molecular beam epitaxy equipment uses ultra-high vacuum (e.g. about 10-1° Torr)
In a growth chamber (vacuum vessel, not shown) that is evacuated to The periphery is covered with, for example, a cylindrical shroud (liquid nitrogen shroud) 2 as shown in the figure, which adsorbs and removes stray evaporated substances.

In that case, liquid nitrogen, for example, is supplied as a refrigerant between the outer wall 21 and the inner wall 22 of the shroud 2.

[Problem that the invention seeks to solve]

As the operation continues, a deposited layer 6 of, for example, arsenic, phosphorus, etc. is adsorbed and accumulated on the inner wall 22 of the shroud 2. If this is left unattended, not only will the adsorption capacity of the shroud 2 decrease and cause vacuum deterioration, but also a portion of the deposited layer 6 will become flakes and peel off, adhering to the substrate 3 and its surface. This may cause defects in the crystals formed, or depending on the arrangement, it may fall into the molecular beam source 4 and cause impurities to be mixed into the evaporation material.

In order to prevent this, it is necessary to remove the deposited layer 6 from time to time. However, in order to do this, conventionally, it was necessary to once break the vacuum in the growth chamber that houses the shroud 2, etc., and remove it, and it was extremely difficult to restore the vacuum in the deposition chamber after the work. for a long time (e.g. 10-”
There was a problem in that the efficiency was very low because it took about one week to raise the temperature to about Torr.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shroud deposit layer removal mechanism that can remove the deposited layer adhered to the inner wall of a vacuum container without breaking the vacuum of the vacuum container housing the shroud.

[Failure to solve the problem]

The deposited layer removing structure for a shroud of the present invention is characterized by comprising a hammer for hitting a shroud provided in a vacuum vessel from outside the vacuum vessel, and a bellows for vacuum sealing the hammer.

[Operation] The shroud can be struck from the atmosphere side with a hammer while keeping the vacuum container vacuum-tight, thereby knocking off the deposited layer adhering to the inner wall of the shroud. Therefore, the efficiency of removing the deposited layer is very high.

〔Example〕

FIG. 1 is a schematic sectional view showing an example in which a shroud deposited layer removing mechanism according to an embodiment of the present invention is attached to a growth chamber. Components equivalent to those in FIG. 3 are given the same reference numerals and their explanations will be omitted.

A shroud 2 as described above is provided in a growth chamber 8, which is a vacuum container and has a cylindrical shape, for example.

7 is the liquid nitrogen mentioned above. In this example, a deposited layer removing mechanism 10 is attached to a flange 9 provided above the growth chamber 8.

The deposition removal mechanism 10 includes a hammer 11 for hitting the shroud 2, more specifically, the outer wall 21 of the shroud 2 downward from outside the growth chamber 8, and a retractable bellows 12 for vacuum-sealing the hammer 11. Further, in this example, a spring 13 is provided which suppresses the expansion of the hollow steel 12 and makes it easier to keep the hammer 11 in a neutral position.

To explain the operation, in order to remove the deposited layer 6 attached to the inner wall 22 of the shroud 2, one end of the hammer 11 is struck by hand from the atmosphere side, the hammer 11 is moved up and down as shown by arrow A, and the other end is used to remove the deposited layer 6 from the shroud 2. Hit 2. As a result, the deposited layer 6 adhering to the inner wall 22 of the shroud 2 is knocked off from the inner wall 22 to be worked. The shroud 2 is normally tilted or directed downward, as shown in FIG. 3, for example. Therefore, the deposited layer 6 that has been knocked off is caused to fall downward from the shroud 2. If necessary, the deposited layer 6 as shown in the figure may be provided at the bottom of the shroud 2.
An opening 14 for dropping may be provided.

As a result of the above-described operation, the surface of the shroud 2 appears, improving the cryo-adsorption effect, and as a result, the degree of vacuum in the growth chamber 8 also improves. Furthermore, since flakes and the like that cause crystal defects are removed, the quality of the film on the substrate 3 is also improved. Moreover, the above operation can be performed while maintaining the ultra-high vacuum in the growth chamber 8 between epitaxial growths, so it is very efficient, and therefore greatly contributes to improving the productivity of the molecular beam eviction apparatus.

Note that, unlike the above, the hammer 11 is used to strike the inner wall 22 to which the deposited layer 6 is attached.

Also good. In this way, the work of removing the deposited layer 6 becomes easier. An example is shown in FIG. That is, Shuratsudo 2
The opening 15 provided in the plate 1 attached to the inner wall 22
6, and by hitting this with a hammer 11, the inner wall 22 is struck isometrically. In that case, plate 16
By fixing only one end of the plate 16 to the inner wall 22, the other end of the plate 16 may flip the inner wall 22, so to speak.

The location where the deposited layer removal mechanism 10 is installed is not limited to the above-described location above the growth chamber 8, but may be mounted at any appropriate location, such as on the side or below the growth chamber 8. Further, the application of the deposited layer removing mechanism 10 is not limited to the cylindrical shroud 2 or the growth chamber 8 as described above, but can of course be widely applied to various shapes and structures. be.

〔Effect of the invention〕

As described above, according to the present invention, the deposited layer adhering to the inner wall of the shroud can be removed from the atmosphere side without breaking the vacuum of the vacuum container housing the shroud.

Therefore, the efficiency of removal work is very high.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an example in which a shroud deposited layer removing mechanism according to an embodiment of the present invention is attached to a growth chamber. FIG. 2 is a partial sectional view showing another example of the shroud portion. FIG. 3 is a schematic perspective view showing an example of a shroud and its surroundings in a molecular beam epitaxy apparatus. 2...Shroud, 21...Outer wall, 22...Inner wall, 6...Deposition layer, 8...Growth chamber (vacuum container), 10
19. Deposited layer removal mechanism, 11...hammer, 12...
・Bellows

Claims (1)

[Claims] (1) A deposited layer removal mechanism for a shroud, comprising a hammer for hitting a shroud provided in a vacuum vessel from outside the vacuum vessel, and a bellows for vacuum sealing the hammer.