JPS6396928A - Vapor deposition apparatus - Google Patents

Abstract

PURPOSE:To limit the amount of evaporation with good controllability even when a material with high vapor-pressure is used as an evaporating source in such a way that a cooling means using liquid nitrogen is installed around at least one crucible at a multiple evaporation apparatus. CONSTITUTION:A first crucible 2 and a second crucible 3 are installed inside a vacuum tank 1; a substrate 4 is arranged at the position facing the crucibles. A heater 21 is wound around the crucible 2; Zn is contained inside this crucible. A heater 31 is wound around the crucible 3; a cooling pipe 32 is installed at the outer circumference of the crucible. S is contained inside the crucible 3. With this setup the tank 1 is evacuated to produce a vacuum; the crucibles 2 and 3 are heated while the temperature is controlled independently of each other so that the amount of evaporation for each crucible can be controlled. As a result, it is possible to obtain a good epitaxial growth layer or a pillar- shaped polycrystal. Because liquid nitrogen is fed to the cooling pipe 32 according to the need and is discharged from the cooling pipe 32, it is possible to cool the crucible easily, with good controllability and uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multi-component evaporation apparatus using a plurality of NR sources, and particularly to the structure of the evaporation source.

[Prior art and its problems] Molecular beam epitaxy is a method of epitaxial growth by applying molecular beams to a substrate in an ultra-high vacuum apparatus of approximately 10” Torr. As shown, a plurality of crucibles are used and the temperature of each crucible is controlled independently.

By the way, when it is desired to reduce the supply of molecular beams, cooling by indirect radiation such as a nitrogen shroud, cooling by heat conduction, etc. are used.

However, substances with high vapor pressure such as sulfur (S)
Under high vacuum (10°'' Torr) such as in BEB, evaporation continues even at room temperature, resulting in a problem of poor controllability.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the controllability of the amount of evaporation and form a deposited film with good crystallization properties in a multi-component vapor deposition apparatus.

[Means to solve the problem]

Therefore, in the present invention, at least one of the crucibles that accommodate the evaporation sources is covered with a cooling pipe that can be filled with liquid nitrogen.

(Function) This method allows the area around the crucible to be cooled uniformly, and can be cooled to near the sublimation temperature of liquid nitrogen, thus preventing the evaporation of substances that easily evaporate, such as sulfur, even under high vacuum. It is possible to obtain a desired deposited film with good controllability.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1(a) is a diagram showing the structure of a multi-component vapor deposition apparatus according to an embodiment of the present invention.

This multi-component vapor deposition equipment uses a multi-component vapor deposition method to produce zinc sulfide (Zn).
S) For forming a layer, a first crucible 2 and a second crucible 3 are arranged in a vacuum chamber 1, and a substrate 4 is arranged at a position facing them.

Then, as shown in FIG. 1(b), the first
A first heater 21 is wound around the crucible 2 and contains zinc (Zn).

Further, a second heater 31 is also wound around the second crucible 3, and the outside thereof is a cooling pipe 32.
Liquid nitrogen can be freely supplied and discharged through an upper filling port 33 and a lower discharge port 34. This contains sulfur (S).

Furthermore, shutters 5 that can be opened and closed are provided near the evaporation ports of the first and second crucibles 2 and 3, respectively.

Further, the vacuum chamber 1 is evacuated to a desired degree of vacuum by a vacuum pump 6, but is connected to the vacuum pump 6 via a copper getter pump 6 [7] to prevent sulfur gas from flowing into the vacuum pump. ing.

Inside this copper getter pump device 117, as shown in FIG. 1(C), three copper plates 71 (FIG. 1(d)) formed into a T-shape are placed in a saucer 70. A heater 72 is suspended between these from above.

In such an apparatus, the vacuum chamber 1 is usually evacuated to a degree of vacuum of about 10"3 to 1o-11, and the first and second crucibles are heated while independently controlling the temperature,
By controlling the amount of evaporation so that the ZnS layer formed on the substrate 4 has a stoichiometric composition, a good epitaxially grown film or columnar polycrystal can be obtained.

Here, liquid nitrogen is supplied from the filling port 33 as needed and discharged to the discharge port 34, so that uniform cooling can be extremely easily performed with good controllability.

Further, since a copper getter pump device is provided, even if sulfur gas flows in, it reacts with the copper plate 71 and becomes copper sulfide (Cub) and adheres thereto, and the sulfur gas does not reach the vacuum pump 6. Therefore, performance deterioration of the vacuum pump can be prevented. Here, the heater 72 promotes the reaction between the copper plate 71 and the sulfur gas. Furthermore, the produced copper sulfide is stable at room temperature and in a dry atmosphere, and there is no fear of re-evaporation or decomposition. Furthermore, the copper plate to which copper sulfide has adhered is extremely easy to handle, as it is only necessary to take out the tray and replace it.

In the example, a cooling pipe was used to control the vapor pressure of sulfur, but not only sulfur but also cadmium (Cd), selenium (
Any material having a high vapor pressure such as Se) or rubidium (Rb) can be used.

Furthermore, although two crucibles are used here, the crucibles are not limited to two.

Furthermore, it goes without saying that the structure of the cooling pipe is not limited to the embodiment and can be modified as appropriate.

In addition, the present invention is applicable not only to molecular beam epitaxy (MBE), but also to so-called multidimensional evaporation (MBE), which uses multiple evaporation sources.
MSD) method is applicable.

〔Effect of the invention〕

As explained above, in the present invention, in a multi-source evaporation apparatus in which temperature is controlled independently using a plurality of evaporation sources, cooling means using liquid nitrogen is provided around at least one crucible. Therefore, even when a material with high vapor pressure is used as an evaporation source, the amount of evaporation can be controlled with excellent controllability, and a highly crystalline WI film can be formed.

[Brief explanation of the drawing]

FIGS. 1A to 1D are diagrams showing a multi-component vapor deposition apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing a normal multi-component vapor deposition apparatus. 1... Vacuum chamber, 2... First crucible, 3... Second
crucible, 21... first heater, 31... second heater, 32... cooling pipe, 33... filling port, 34...
...Discharge port, 4... Board, 5... Shutter, 6...
・Vacuum pump, 7...Copper getter pump, 70...Saucer, 71...Copper plate, 72...Heater. Figure 1 (α) Figure 1 (d)

Claims (2)

[Claims] (1) A vapor deposition apparatus comprising a vacuum container, a plurality of evaporation sources disposed in the vacuum container, and a vacuum evacuation means for evacuating the inside of the vacuum container, and in which the amount of evaporation of these is independently controlled, At least one of the crucibles accommodating the evaporation source is covered with a cooling pipe filled with liquid nitrogen, and the cooling pipe can freely take in and out the liquid nitrogen, and can maintain the crucible at a temperature lower than room temperature. A vapor deposition apparatus characterized by being able to perform. (2) The evacuation means includes a getter space at the connection part with the vacuum container, and a copper plate is disposed in the getter space to capture sulfur. The vapor deposition apparatus described in item 1).