JPH0437689A - Molecular beam epitaxy equipment - Google Patents

Abstract

PURPOSE:To raise mechanical reliability and to improve degassing at a time for loading by combining a raw material loading device provided with a raw material vessel made of shape memory alloy with both a base plate heating mechanism and a molecular beam source cell. CONSTITUTION:In a state wherein a gate valve 5 is closed and a load lock part is regulated to the atmospheric pressure, Ga 9 being the raw material of GaAs-based material is loaded into a vessel 7 made of shape memory alloy from an introducer 11. Then, after the load lock chamber is vacuumized, the vessel 7 is heated at 40 deg.C by an ionization vacuum meter probe 10 or a heater positioned in the same position and the raw material Ga 9 is melted. Then the gate valve 5 is opened and the vessel 7 is transferred just above a crucible provided to a Ga molecular beam source by a magnet. At this time, the crucible 12 is heated at about 900 deg.C. The vessel 7 receives thermal radiation emitted from the crucible and is heated at about >=80 deg.C. The raw material 9 is allowed to thoroughly fall into the crucible because the vessel 7 made of Ti/Ni alloy is deformed to a previously memorized shape by this heating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a raw material load lock mechanism for a molecular beam epitaxy apparatus.

[Conventional technology]

Conventionally, the raw material load lock device for molecular beam epitaxy equipment (hereinafter abbreviated as MBE) was described in the Journal of
Vacuum Science and Technology B6. (
198'8) pages 1657 to 1661 (J, V
ac, Sci, Technol, B6 (1988
) discussed in PP 1657-1661).

Conventionally, as shown in FIG. 2, a container 7 loaded with raw materials to be supplemented is tilted by rotating a magnet 4 provided outside the vacuum, and placed in a crucible provided within a molecular beam source cell 3. Raw materials were supplemented by dropping raw materials into them.

[Problem to be solved by the invention]

In the above conventional technology, the raw material container 7 provided in the row 1 row section
When the raw material (Ga) is dropped into the crucible 3, the raw material container is rotated from outside the vacuum, so mechanical failure of the rotary drive unit is likely to occur, resulting in low reliability. Furthermore, with the rotational drive method, it is difficult to accurately control the rotation angle.

The present invention aims to provide a molecular beam epitaxy apparatus equipped with a raw material load lock having high mechanical reliability, and further aims to provide a load lock apparatus that causes less outgassing during loading.

[Means to solve the problem]

In order to achieve the above object, in the present invention, in the raw material load lock mechanism provided in the molecular beam epitaxy apparatus,
By using a shape memory alloy for the raw material container or a part of it, when dropping the raw material into the molecular beam source crucible using a load lock, only the radiant heat of the molecular beam source can be used without using external mechanical driving force. This is to drive the raw material container.

Furthermore, in order to suppress de-slag in the vacuum container, we heat only the necessary parts in a load-lock chamber separated from the growth chamber, or melt the raw materials and fully degas them before supplying them to the growth chamber. It is designed to transport the desired raw materials.

[Effect]

In the MBE raw material load lock mechanism according to the present invention, the third
As shown in the figure, the raw material loading container has the shape (a) at room temperature, and when transferred onto the molecular beam source cell, the shape memory alloy changes to the shape (b) due to radiant heat from the molecular beam source. As shown in (b), raw materials can be dropped into the Lupo 12 without any operation from outside the vacuum.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 A first example will be described using FIGS. 1 to 3. First, as shown in FIG. 2, a growth chamber 1. A conventional MBE apparatus consisting of a liquid nitrogen shroud 22 and a molecular beam source cell 3 was installed. Magnet 4. Goo 1-Valve 5. In a raw material load lock mechanism consisting of a raw material introduction port 6 and a raw material container 7, a Ti/Ni alloy was used for the raw material container 8:;7.

The first diagram shows a detailed view of the raw material load lock section.

With the gate valve 5 shown in FIG. 2 closed and the rotor lock section set to atmospheric pressure, GaAS is
Ga9, which is the raw material for the based material, is stored in a shape memory alloy raw material container 7.
to be loaded. Next, after evacuating the lock chambers from Row 1 to
The container 7 is heated to 40° C. using the ionization vacuum gauge probe 1o or a heater installed at the same position, and the raw material (Ga) 9 is melted. At this time, the container 7 maintains the shape shown in the figure.

Thereafter, the gate valve 5 is opened, and the container 7 is moved by a magnet to a position directly above the crucible (12 in FIG. 3(b)) provided in the Ga molecular beam source. At this time, the crucible 12 is heated to 900°C. Container 7 receives heat radiation from 12 and reaches 80°C.
It is heated to

T]/Ni alloy container 7 is deformed into a pre-memorized shape (FIG. 3(b)) by this heating, so that all the raw materials 9 are dropped into the melter 12.

According to this embodiment, when loading raw materials into the crucible 12, the raw material container is deformed only by . With precise position control, raw materials can be replenished.

Example 2 The second embodiment will be explained in detail using Figures 1 and 1.

L! Material volume 8: (The method for transferring 7 to the molecular beam source and the upper part of the cell is the same as in the first embodiment. In the 4th r near +, the raw material container is placed in the molecular beam source cell -. Immediately after transferring (2
1), and the shape after 5 minutes is shown in (b).

In this example, the raw material container 7 was made of BaiIJ Tinokuboronai 1 Herite. The container consists of two parts, and the two parts are held together by hinges 14.

Additionally, T i /N ] alloy springs 13 are fixed on the two parts.

At room temperature, the spring 13 is fully extended as shown in Figure (a), and Ga9 is held within the container.

The spring 13, heated to about 100'C by the radiant heat from the molecular beam source, contracts, as shown in Figure (b).
The bottom of the container opens and raw material 9 is dropped into the molecular beam source.

〔Effect of the invention〕

According to the present invention, the raw material container partially using a shape memory alloy can drop the raw material into the molecular beam cell without being driven from the outside, so it is effective in preventing drive unit failure and vacuum leaks. be.

Furthermore, since no external drive is required, the volume of the rotorlock chamber can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a load lock section according to a first embodiment of the present invention, FIG. 2 is a schematic vertical cross-sectional view showing a conventional raw material load lock mechanism, and FIG. FIG. 4 is a sectional view of a raw material container according to a second embodiment of the present invention. 1. Growth chamber, 2. Liquid nitrogen shroud, 3. Molecular beam source cell, 4. Magnet, 5. Gate valve, 6-D! Raw material introduction port, 7. Raw material container, 9 Raw material, 10. Heater or vacuum gauge probe, 11. Raw material introduction device, 12. Crucible, 13.
- Hane, 14 - Hinge.

Claims (1)

[Scope of Claims] 1. A molecular beam epitaxy device comprising a substrate heating mechanism, a molecular beam source cell, and a raw material load-lock mechanism, wherein the raw material load-lock device is provided with a raw material container at least partially made of a shape memory alloy. Features of molecular beam epitaxy equipment. 2. Claim characterized in that the heating mechanism has a heating function of heating the raw material above its melting point, and also has a function of controlling the temperature to be lower than the radiation heating temperature by the molecular beam source in the upper part of the molecular beam source cell. 1. The molecular beam epitaxy apparatus according to 1. 3. The molecular beam epitaxy apparatus according to claim 1 or 2, wherein the heating mechanism comprises a vacuum probe provided at a position facing the raw material. 4. The molecular beam epitaxy apparatus according to claim 1, wherein the phase transition temperature of the shape memory alloy container provided in the raw material load-lock mechanism is higher than the melting point of the raw material and lower than the radiation temperature from the molecular beam source. . 5. The molecular beam epitaxy apparatus according to claim 4, wherein the phase transition temperature is higher than the Ga melting point.