JPH03146659A - Method and device for vacuum vapor deposition - Google Patents

Abstract

PURPOSE:To lessen the change in the intensity distribution of the molecular beam by gouging of an evaporating sample by an electron gun by tilting the evaporating sample toward a filament side as the molecular beam intensity detected on the filament side of an electron gun type evaporating source decreases. CONSTITUTION:After the inside of a vacuum vessel is evacuated to a vacuum, the electron gun type evaporating source 1 is operated and the evaporating sample 9 is irradiated with the electron beam to form the thin film of the sample 9 on the surface of a substrate 17. The part of the sample 9 irradiated with the electron beam is gouged along an electron orbit 8 and the intensity distribution of the molecular beam on the substrate 17 changes according to the continuation or repetition of such vapor deposition. The intensity change is detected by a crystal resonator sensor 2 and the sample 9 is tilted in an arrow 16 direction to maintain the molecular beam intensity detected by the sensor 2 at approximately the specified intensity. As a result, the specified intensity distribution of the molecular beam is obtd. even on the substrate 17 and, therefore, the thickness distribution of the thin film on the substrate 17 is uniformized as the substrate 17 is provided with a specified rotating motion by a known substrate driving mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vacuum evaporation method and apparatus using an electron gun type evaporation source.

(Prior Art) Conventionally, in a vacuum evaporation apparatus (including molecular beam epitaxy), it has been known to use an electron gun type evaporation source when evaporating a sample with a low vapor pressure. Generally, when an electron gun type evaporation source is used, the electron beam is angularly deflected by a magnetic field and irradiated with the evaporated sample in order to prevent the evaporated matter from flying into the electron gun, which is the source of the electron beam. ing.

(Problem to be Solved by the Invention) In a conventional vacuum evaporation apparatus that uses an electron gun type evaporation source as described above to evaporate a sample with a low vapor pressure, an electron beam is deflected by a magnetic field to evaporate the evaporated sample. During the initial stage of evaporation, the electron beam was incident perpendicularly to the evaporated sample, but as evaporation continues or is repeated, the electron beam irradiated part of the evaporated sample moves along the trajectory of the electron beam. The electron beam is no longer incident perpendicularly to the evaporated sample, and
A protrusion that did not melt was formed on the upper filament (electron beam generation source) side of the electron beam irradiation section.

As a result, on the substrate on which the thin film is to be deposited, the molecular dose on the protrusion side decreases, the film thickness distribution on the substrate becomes uneven, and reproducibility between multiple substrates is also improved. This was a problem that could not be solved.

This invention solves the above-mentioned problems and provides a vacuum evaporation method that reduces changes in the intensity distribution of molecular beams due to the electron beam digging into the evaporated sample, and that always provides the same film thickness distribution on the substrate. and equipment.

(Means for Solving the Problems) That is, the vacuum evaporation method of the present invention is a method of evaporating a thin film of an evaporated sample from the electron gun evaporation source onto the substrate with the substrate facing the electron gun evaporation source. The method is characterized in that the evaporation sample is tilted toward the filament side in accordance with a decrease in the molecular beam intensity detected on the filament side of the electron gun type evaporation source in the space.

A vacuum evaporation apparatus of the present invention for carrying out the above method includes an electron gun type evaporation source and a molecular beam monitor installed on one side above the evaporation source.
The molecular beam monitor is installed above the filament side of the electron gun type evaporation source, and the evaporation source has a tilting table for supporting the evaporated sample and a tilting mechanism for tilting the tilting table. The tilting mechanism is controlled by a tilting controller that receives an output from a molecular beam monitor.

(Function) According to the vacuum evaporation method and apparatus of the present invention, the intensity distribution of the molecular beam with respect to the substrate in the evaporation source can be made to follow the cosine law of the path even if the evaporation is continued or repeated. can.

(Embodiments) Hereinafter, embodiments of the present invention using a 270-degree deflection type electron gun type evaporation source will be described with reference to the drawings.

FIG. 1 shows the internal configuration of a vacuum container (not shown) in the vacuum evaporation apparatus of this embodiment. Sensor 2 is installed. In the electron gun type evaporation source 1, the filament 3 is heated by a constant current power source 4, and a constant voltage power source 6 is connected between the filament 3 and the grid 5.
Electrons are extracted from the filament 3 and accelerated by the applied voltage.

The accelerated electrons are deflected by the deflection magnetic field 7, and as a result are deflected by 270 degrees along an electron trajectory 8, and are irradiated onto the evaporated sample 9.

The evaporated sample 9 is supported on a tilting table 11 that can be rotated as shown by an arrow 10a around a horizontal axis 10 parallel to the direction of the deflecting magnetic field 7. Tilting mechanism 12 (for example, composed of a cam mechanism such as an eccentric wheel)
Rotation is controlled by .

On the other hand, the crystal oscillator sensor 2 is connected to a controller 13 to form a film thickness meter, and a deposition rate signal 14 calculated by the controller 13 is sent to a tilting controller 15 that controls the tilting mechanism 12. It is given.

The tilting controller 15 has a comparator as a main circuit element, and controls the tilting mechanism 12 so that the preset deposition rate and the deposition rate signal 14 given from the film thickness meter are approximately constant.
The tilting table 11 is configured to be tilted in the direction of an arrow 16 via a tilting mechanism 12 in accordance with the output of the comparator.

In the above embodiment, when the electron gun type evaporation source 1 is operated after evacuating the inside of the vacuum container, the evaporation sample 9 is irradiated with an electron beam, and a thin film of the evaporation sample 9 is formed on the surface of the substrate 17. can do.

If such deposition is continued or repeated,
The electron beam irradiation part of the evaporation sample 9 digs in along the electron trajectory 8, and the intensity distribution of the molecular beam with respect to the substrate 17 changes, but the change in the intensity of the molecular beam is detected via the crystal oscillator sensor 2. , the evaporated sample 9 is tilted in the direction of the arrow 16, and the molecular beam intensity detected by the quartz crystal sensor 2 is kept approximately constant. As a result, the intensity distribution of the molecular beam is approximately constant on the substrate 17, so that the substrate 17 can be rotated by a known substrate drive mechanism (for example, a planetary mechanism) to drive the thin film on the substrate. The film thickness distribution can be made uniform.

FIG. 2 shows an investigation of the film thickness distribution on the fixed substrate in the example. The center normal of the substrate 17 is offset from the center normal of the evaporation sample 9 to the filament 3 side by 20 m+g,
Vapor deposition was performed without rotating the substrate 17. The n1 constant was performed on the substrate 17 from the filament 3 side of the electron gun type evaporation source 1 toward the evaporation sample 9 side. Figure 2 (al is the film thickness distribution of the first substrate, and Figure 2 (b) is the film thickness distribution of the 30th substrate. The film thickness distribution on the fixed substrate is evaporated sample 9.
It was confirmed that this corresponds to the distribution of the molecular beam intensity with respect to the substrate 17, and that the molecular beam intensity distribution was maintained approximately uniform from the first to the 30th substrate.

Figure 2 (C) shows the film thickness distribution of the 30th substrate when evaporation was repeated without tilting the evaporation sample 9, and the film thickness on the side dug by electron beam irradiation (filament 3 side). It can be seen that the beam is thinner and the intensity of the molecular beam is lower.

The film thickness distribution (in-plane distribution) in Figures 2 (a) and (b) is due to the molecular beam distribution according to the cosine law, and a uniform in-plane thickness distribution can be obtained by rotating the substrate. Needless to say. That is, in the vacuum deposition method and apparatus of the present invention,
By rotating the substrate, a uniform film thickness distribution can always be obtained.

(Effects of the Invention) As explained above, according to the present invention, the molecular beam intensity distribution with respect to the substrate in the evaporation source can be made constant;
A uniform thin film can be repeatedly formed on a substrate without replacing the evaporation sample, which has the effect of providing reproducibility.

In particular, in molecular beam epitaxy, the frequency of opening the vacuum container to the atmosphere for exchanging evaporated samples is reduced, and there are fewer impurities.
Moreover, it has the effect of forming a high-quality thin film with few crystal defects.

4,

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a device embodying this invention, and Figure 2 (a
) to (C) are graphs of the film thickness distribution, and FIG. 2(a) is a graph of the film thickness distribution of the first substrate in the example.
b) is the same (the 30th film thickness distribution graph in Example), and Figure 2 (C) is the 30th film thickness distribution graph in the case where the evaporation sample is not tilted.
This is a graph of the film thickness distribution. 1...Electron gun type evaporation source 2...Crystal oscillator sensor 3...Filament 8...Electron trajectory 9...Evaporation sample 11...Tilt table 12...Tilt mechanism
15... Tilt controller 17... Board

Claims (1)

[Scope of Claims] 1. In a method of depositing a thin film of an evaporated sample of the electron gun evaporation source onto the substrate by placing the substrate facing the electron gun evaporation source, Vacuum deposition method 2, characterized in that the evaporated sample is tilted toward the filament side in accordance with a decrease in the molecular beam intensity detected on the filament side.An electron gun type evaporation source and molecules installed on one side above the evaporation source. In the vacuum evaporation apparatus, the molecular beam monitor is installed above the filament side of an electron gun type evaporation source, and the evaporation source includes a tilting table for supporting the evaporated sample, and a tilting table for supporting the evaporation sample. A vacuum evaporation apparatus characterized in that it has a tilting mechanism for tilting the table, and the tilting mechanism is controlled by a tilting controller that receives an output from a molecular beam monitor.