JPH03159989A - Vacuum deposition apparatus - Google Patents

Abstract

PURPOSE:To enable the evaporation of an evaporation source over a long period in high efficiency by heating a crucible at a temperature higher than the heating temperature of the evaporation source with a heater attached to the upper part at a side of the crucible for evaporating the evaporation source. CONSTITUTION:The objective vacuum deposition apparatus is provided with a crucible 2 for evaporating an evaporation source 1, a furnace 3 to heat the crucible 2, a liquid nitrogen shroud 4 for cooling the circumference of the furnace 3, a substrate holder 6 for holding a substrate 5 to be subjected to vacuum deposition with the evaporation source 1, a chamber 7 for holding the furnace 3, the liquid nitrogen shroud 4 and the substrate holder 6, an evacuation system 8 to evacuate the chamber 7 to high vacuum, a shutter 11 for controlling the intensity of molecular beam evaporated from the evaporation source 1 and a means for depositing the material evaporated from the evaporation source 1 to the surface of the substrate 5. In the above construction, a heater 9 for heating the crucible at a temperature higher than the heating temperature of the evaporation source is attached to the upper part at a side of the crucible 2.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to the structure of a crucible in a vacuum evaporation apparatus, and aims to prevent the evaporation source from climbing up to the top of the crucible and to efficiently evaporate the evaporation source for a long time. a crucible for evaporating the crucible, a furnace for heating the crucible, and a liquid nitrogen shroud for cooling the circumference of the furnace. a substrate holder for holding a substrate on which the deposition source is to be deposited, and a chamber for housing the furnace, liquid nitrogen shroud, and substrate holder.
A vacuum evaporation apparatus comprising: an evacuation system that draws the chamber to a high vacuum; a shutter that controls the amount of molecular beams evaporated from the evaporation source; and a means for depositing the evaporation source onto the surface of the substrate; A heater that heats at least a temperature higher than the heating temperature of the vapor deposition source is provided above the vapor deposition source.

[Industrial application field]

The present invention relates to the shape of a crucible for a vacuum evaporation apparatus.

recent years. Vacuum deposition equipment. Especially in MBE length equipment,
There is a need for a technology to stably evaporate a deposition source such as AI2 for a long time.

For this reason, various improvements to crucibles are required.

[Conventional technology]

FIG. 4 is an explanatory diagram of a conventional example.

Conventionally, molecular beam epitaxial (Molecular B
eamEpitaxy: Heat-resistant boron nitride (pyrolyt) used in high vacuum evaporation equipment such as MBE
tic Boron Nitride: PBN) Crucible 12 is. As shown in FIG. 4, it has an open conical trumpet shape and is heated by a heater 15 installed inside the furnace 13.

When performing compound semiconductor crystal deposition, the evaporation source 1l on the substrate should be . As a crystal source, gallium (Ga),
Arsenic (As), Indium (In)I Aluminum (AI!.), Boron (B) as a dopant source,
Various materials such as silicon (St) are used.

Aluminum as the evaporation source 11 melts in a vacuum, and also forms a fresh molten surface near the evaporation temperature, but this liquid surface is extremely active and improves wetting with the surface of the pBN crucible 12.

Therefore. It creeps up the wall of the crucible 12 due to capillary action, and in the worst case, it overflows outside the crucible 12.

The upper part of the crucible 12 is covered with a liquid nitrogen shroud 14 for cooling. Afi solidifies in the upper part of the crucible 12, and the opening on the upper surface of the crucible 12 becomes narrower, thereby hindering the molecular beam evaporation of Al.

This phenomenon damages the vacuum equipment, especially the furnace l3 part. In the worst case scenario, the shutter cannot be opened or closed, leaving Affi unattended for a long time. This makes stable vapor deposition difficult.

[Problem to be solved by the invention]

Therefore, a problem has arisen in which Al cannot be effectively deposited.

The present invention is based on AI! ．． This is provided for the purpose of suppressing vapor deposition sources such as those from creeping up to the top of the crucible and allowing efficient vapor deposition over a long period of time.

[Means to solve the problem]

FIG. 1 is an explanation of the principle of the present invention.

FIG. 2 is a diagram of the structure of a molecular beam epitaxial apparatus (MBE).

In the figure, ■ is a deposition source, 2 is a crucible, and 3 is a furnace. 4 is liquid nitrogen shroud. 5 is a substrate, 6 is a substrate holder, and 7 is a chamber. 8 is the exhaust system. 9 is a heater.
10 is a heater, and 1.1 is a shutter.

Since the creeping up of the vapor deposition source 1 to the upper part of the inner wall of the crucible 2 has the property of proceeding from the higher temperature side to the lower temperature side, it is necessary to reduce the temperature distribution on the inner wall of the crucible 2 or to lower the temperature at the upper part of the crucible 2. By setting the height higher than the deposition source 1, the creeping up of the deposition source 1 can be suppressed.

That is. The above problems are caused by the crucible 2 for evaporating the deposition source 1 of the present invention, the furnace 3 for heating the crucible 2, and the liquid nitrogen shroud 4 for cooling the surroundings of the furnace 3. a substrate holder 6 for holding a substrate 5 on which the vapor deposition source 1 is to be vapor deposited; a chamber 7 that accommodates the furnace 3, the liquid nitrogen shroud 4, and the substrate holder 6; and an exhaust system 8 that draws the chamber 7 to a high vacuum;
In a vacuum evaporation apparatus comprising: a shank 11 for controlling the amount of molecular beam evaporated from the evaporation source 1; and means for depositing the evaporation source 1 onto the surface of the substrate 5. This problem can be solved by providing a heater 9 above the side surface of the crucible 2, which heats the crucible to a temperature higher than at least the heating temperature of the vapor deposition saw 1.

[Operation] In the present invention, as shown in FIG. By heating the upper part of the crucible with a heater, it is possible to prevent l from creeping up to the upper part, and therefore, efficient and long-term vapor deposition is possible without narrowing the effective diameter of the crucible.

〔Example〕

FIG. 3 is an explanatory diagram of an embodiment of the present invention.

In the figure, 2 is a crucible, and 9A, 9B, and 9C are heaters for each crucible.

Using the MBE apparatus shown in FIG. 2, AnG was deposited on the substrate 5.
A case will be described in which a compound semiconductor crystal of aIn is crystallized.

The device has 8 molecular beam epitaxial deposition sources 11
can be installed. In the example,
Three types of evaporation sources are used: AI2, Ga, and In.

The chamber 7 is heated to 10-" by the ion pump of the exhaust system 8.
After drawing a high vacuum of ~10-'' Torr, the evaporation source l loaded in the crucible 2 is heated by the heater 10 in the furnace 3, and the molecular beam is released by opening and closing the shutter 11 provided in the front of the crucible 2. Molecular beam evaporation is performed by controlling the

At this time, in order to prevent each part of the chamber 7 from being heated and generating gas and reducing the degree of vacuum, each part of the chamber 7, including the area around the furnace 3, is cooled by the liquid nitrogen shroud 4.

A1 of vapor deposition source I was heated to 900-1+000°C, Ga to 700 to 900°C, and In to 500 to 700°C. All! Although a GaIn compound semiconductor is used, the heating temperature of the vapor deposition source 1 is determined within the heating temperature range according to the composition ratio of the ternary metal compound.

AI! ．． The crucible 2 containing the vapor deposition source 1 is shown in FIG.
As shown in a). A belt-shaped sheet heater 9A wrapped only around the upper part of the outer wall of crucible 2 was used, but as shown in Fig. 3 (
As shown in b), a linear heater 9B is spirally wound around the upper part of the outer wall of the crucible 2, or as shown in FIG. 3(c), a heater 9C is attached to the entire outer wall of the crucible 2. A structure in which the entire crucible 2 is directly heated using the furnace 3 can also be effectively used.

〔Effect of the invention〕

As explained above. According to the invention. The evaporation source can be prevented from climbing up the inner wall without damaging the effective evaporation aperture of the evaporation source, without damaging the vacuum equipment. Stable deposition can be continued for a long time.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the principle of the present invention. Figure 2 is a configuration diagram of the MBE device. FIG. 3 is an explanatory diagram of an embodiment of the present invention. FIG. 4 is an explanatory diagram of a conventional example. In the figure, 1 is vapor deposition source 3 is the furnace 5 is the board 5 7 is the chamber 9 is a heater 2. Crucible. 4 is liquid nitrogen shroud 6 is the board holder 8 is the exhaust system, 10 is a heater 9

Claims (1)

[Scope of Claims] A crucible (2) for evaporating the vapor deposition source (1), a furnace (3) for heating the crucible, a liquid nitrogen shroud (4) for cooling the surroundings of the furnace, and a crucible for evaporating the vapor deposition source (1). a substrate holder (6) that holds a substrate (5) to be deposited; a chamber (7) that accommodates the furnace, liquid nitrogen shroud, and the substrate holder; an exhaust system (8) that draws the chamber to a high vacuum; A vacuum evaporation apparatus comprising: a shutter (11) for controlling the amount of molecular beam evaporated from the evaporation source; and means for evaporating the evaporation source onto the surface of the substrate; A vacuum evaporation apparatus characterized by being provided with a heater (9) that heats to a temperature higher than the heating temperature.