JP2820471B2 - Thin film forming equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thin film forming apparatus in which an evaporation source and a substrate support mechanism are installed opposite to each other in a vacuum vessel, and remains in a thin film forming space after forming a thin film. This makes it possible to remove the evaporant generated.

(Prior Art) Conventionally, an apparatus as shown in FIG. 3 has been used as a thin film forming apparatus for forming a polycrystalline film or a single crystal film.

In the drawing, reference numeral 1 denotes a vacuum container, which constitutes a thin film forming chamber, in which a plurality of evaporation sources 2a, 2b,... 2d and a substrate support capable of rotating and heating the substrate 3 are provided. The member 4 is installed facing the member. The evaporation sources 2a, 2b,... 2d and the substrate support member 4 are surrounded by a liquid nitrogen shroud 5 in order to adsorb impurity gas released when they are heated. In the figure, reference numeral 6 denotes an exhaust device connected to the vacuum vessel 1.

In this apparatus, a plurality of substances are simultaneously emitted from a plurality of evaporation sources 2a, 2b,... 2d to form, for example, a single crystal thin film of a group III and V or a group II and VI element compound on the surface of the substrate 3. Alternatively, a plurality of substances are alternately released to form a superlattice thin film in which a plurality of elemental compounds are alternately thinly stacked.

(Problems to be Solved by the Invention) In forming the superlattice thin film, it is required that each element compound is completely independent at an interface. It was difficult to make the interface completely independent.

For example, when a superlattice thin film (for example, GaAs and GaSb) is formed of two kinds of elements which have the same group III element but different group V elements, the interface between the two kinds of binary compounds has the group V element. There was a problem that a ternary mixed crystal compound (GaAsSb) containing seeds was present.

This was recognized because the group V element (As or Sb) remained near the substrate even after the formation of one thin film and was mixed in when forming the other thin film.

An object of the present invention is to solve such a problem and to provide a thin film forming apparatus capable of removing evaporated substances remaining in a thin film forming space.

(Means for Solving the Problems) According to a thin film forming apparatus of the present invention, a thin film forming apparatus in which a plurality of evaporation sources and a substrate supporting member are opposed to each other in a vacuum vessel is provided. A thin film forming apparatus characterized in that an attachment plate capable of moving inside the vacuum vessel by power from the outside of the vacuum vessel for removing evaporated substances remaining in the space is installed so as to be able to be separated from and brought into contact with the substrate support member. It is.

The adhering plate is reliably coated by a surface coating with a substance having an adhering coefficient of about 1 with respect to the remaining evaporant. Further, a heating mechanism is provided to re-emit and remove the residual evaporant attached to the attachment plate.

(Function) In the thin film forming apparatus of the present invention, the evaporation plate remaining in the thin film formation space can be adhered to the adhesion plate by bringing the adhesion plate close to the substrate support member. Therefore, the superlattice thin film as described above can also be formed independently of the interface between the elemental compounds.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG. 1 and FIG.

A liquid nitrogen shroud 15 is provided inside the vacuum vessel 11, and two group V evaporation sources 12a and 12b and two group III evaporation sources 12c are provided so as to penetrate the lower part of the inside of the liquid nitrogen shroud 15. , 12d are provided, and a substrate support member 14 is provided above the vacuum vessel 11 so as to face these evaporation sources. The substrate supporting member 14 can support the substrate 13 on the lower surface, and also has a function of rotating and heating the supported substrate. Above evaporation source
Each of 12a, 12b,... 12d is provided with shutter plates 17a, 17b, 17c, 17d for opening and closing the evaporant discharge section, and can be operated from outside the vacuum vessel 11.

The shaft 20 of the rotation introducing machine 19 installed on the top wall of the vacuum vessel 11 is introduced into the thin film formation space 18 where the substrate 13 faces the evaporation sources 12a, 12b,. The attachment plate 21 is connected at a right angle, as shown in FIG.
The attachment plate 21 can rotate between A and B.
Further, a heater 22 is provided on the attachment plate 21 so that electric power can be supplied through a lead wire 23 so that the attachment plate 21 can be heated. In the figure, reference numeral 16 denotes an exhaust device for the vacuum vessel 11.

Next, in the above embodiment, two kinds of binary compounds, that is, GaAs and Ga
The case of forming an ultra-thin Sb film will be described.

As for the V-group evaporation source 12a, As is used for the V-group evaporation source 12b.
While the Sb is filled, the group III evaporation source 12c is filled with Ga.

First, it goes without saying that each of the evaporation sources 12a, 12b, 12c and the filled evaporation substance are heated to perform degassing.

After the degassing, the shutter plates 17b and 17c are first opened, and a binary GaAs compound thin film is formed on the substrate 13 for a predetermined time. At this time, it is assumed that the attachment plate 21 is at the position A in FIG.

When the formation of the GaAs thin film is completed, the shutter plates 17b and 17c
Is closed, and the attachment plate 21 is moved from the position A to the position B via the rotation introducing device 19. By the movement of the attachment plate 21, As of the group V element remaining near the substrate 13 can be attached to the attachment plate 21 and removed.

Next, the shutter plates 17a and 17c are opened, and the GaSb
Is formed for a predetermined time.

When the formation of the GaSb thin film is completed, the shutter plates 17a, 17c
Is closed, and the attachment plate 21 is moved from the position B to the position A, whereby Sb of the group V element remaining on the substrate 13 can be attached to the attachment plate 21 and removed.

It is desirable that the adhesion plate 21 has a high adhesion coefficient with respect to the residual element to be removed. In the example, Ga (In may be used) having an adhesion coefficient of 1 is coated on the group V element (As, P, Sb).

As a result, the pressure of the group V element can be reduced to 1/100 or less due to the proximity of the attachment plate 21 to the substrate, and the GaAs of the first layer can be reduced.
In addition, the composition ratio of both GaSb and the second layer could be made approximately 1: 1.

Further, after the formation of the superlattice thin film, by heating the adhesion plate 21 by the heater 22, the group V element (As, Sb) adhered to the adhesion plate can be re-evaporated. The elements remaining in the formation space 18 could be removed.

In the embodiment, the attachment plate 21 is rotated around the axis 20 so that the attachment plate 21 can be separated from and connected to the substrate supporting portion 14. However, the present invention is not limited to this configuration, and may be performed via a linear motion introducing machine or the like. Other structures, such as being detachable, are also possible.

(Effects of the Invention) As described above, according to the present invention, by moving the adhesion plate, the evaporated matter remaining in the thin film forming section can be easily removed, and thus the superlattice thin film having a completely independent interface. Has the effect that it can be manufactured. If the surface is coated with a substance having an adhesion coefficient of about 1 with respect to the residual evaporant, there is an effect that the removal can be ensured. Further, by providing the heating mechanism, there is an effect of facilitating re-emission of the residual evaporant.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an embodiment of the present invention, FIG. 2 is a schematic plan view of the same embodiment, and FIG. 3 is a schematic sectional view of a conventional apparatus. 1, 11 vacuum chamber, 3, 13 substrate 4, 14 substrate support member 12a, 12b, 12c, 12d evaporation source 21 adhesion plate 22, heater

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C23C 14/00-14/58 H01L 21/203

Claims (3)

(57) [Claims] 1. A thin film forming apparatus comprising a plurality of evaporation sources and a substrate supporting member installed in a vacuum vessel so as to face each other, and a vacuum for removing evaporated substances remaining in a space near the substrate supporting member after the thin film is formed. A thin film forming apparatus characterized in that an adhesion plate that can move inside the vacuum container by power from the outside of the container is installed so as to be able to be separated from and connected to the substrate support member. 2. The thin film forming apparatus according to claim 1, wherein the adhesion plate is surface-coated with a substance having an adhesion coefficient of about 1 with respect to the remaining evaporant. 3. The thin film forming apparatus according to claim 1, wherein the attachment plate is provided with a heating mechanism.