JPH05222534A - Vapor deposition device - Google Patents

Abstract

PURPOSE:To provide the vapor deposition device which is applicable to a method for precise formation of thin films, adds carbon at a precise addition ratio into the films and produces the films at the extremely small thickness of the formed films with high accuracy. CONSTITUTION:This vapor deposition device accelerates the electrons released from a hot filament 2 in a vacuum, deflects the electrons by a magnetic field or electric field and irradiates a material 6 to be evaporated with these electrons as an electron beam 9, thereby heating and evaporating this material. The material to be evaporated is the carbon. A crucible 3 housing this carbon, the surface of the circumferential part of this crucible and hearth parts 5A, 5B for deflecting the orbit of the electrons are respectively coated with a carbon material 7. Further, a thermocouple 10 which comes into contact with the surface of the circumferential part of the crucible housing the material to be evaporated and a control means which is inputted with the output signal of this thermocouple and controls the power feed rate to the hot filament so as to maintain the output value of the thermocouple at a prescribed value are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition apparatus, and more particularly to improvement of an electron gun type vapor deposition apparatus for doping carbon.

[0002]

2. Description of the Related Art A conventional electron gun type vapor deposition apparatus for adding carbon basically has a crucible for containing carbon, which is a vaporizing substance, a surface around the crucible including the crucible, and a vaporizing substance for vaporizing the vaporizing substance. The hearth portion for bending the electron beam with which the vaporized material is irradiated is formed. Usually, the crucible is made of copper, the surface including the crucible is also made of copper, and the hearth portion is made of nickel. In such a configuration, the evaporation material contained in the crucible is provided with an electron beam having a required energy amount to evaporate the evaporation material. The evaporated carbon moves upward and is mixed as an impurity in the surface film of the substrate arranged above.

[0003]

In the conventional vapor deposition apparatus for carbon addition, an electron beam generated by a hot filament is controlled by a magnetic field or an electric field to irradiate a vapor deposition material (carbon) or scan the vapor deposition material. I was going to do it. In this case, the electron beam (primary beam) may be applied to a portion other than the evaporated substance. When the electron beam is applied to a portion other than the vaporized substance, substances other than the vapor-deposited material are mixed in the vapor, and impurities are mixed in the vapor deposition film. That is, copper and nickel other than carbon are mixed as impurities. In addition, the electron beam applied to the vapor deposition material may subsequently collide with the surface around the crucible and the hurst portion due to the reflection action, and the impurities may evaporate from the collision portion to cause the contamination of the impurities. Therefore, with respect to a precise thin film growth method, for example, a molecular epitaxy method capable of controlling a monoatomic layer and an impurity concentration, the electron gun type vapor deposition apparatus has a problem that impurities are mixed as described above. The mold vaporizer could not be used. Instead, an evaporation source called a molecular beam cell with temperature control was used. Further, when manufacturing a P-type doped semiconductor, a highly toxic element called beryllium must be used as an impurity in a GaAs film. Further, as another problem in the electron gun type vapor deposition device, there is a problem of controlling the evaporation amount of the evaporation material. Conventionally, the amount of evaporation is controlled by directly measuring the thickness of a film produced by a film thickness monitor using a crystal oscillator. This film thickness monitor cannot be generally used with a film thickness of several microns, and it is impossible to measure the film thickness at the angstrom level.
There was also a problem that the film thickness monitor had to be replaced frequently.

An object of the present invention is to provide a vapor deposition apparatus which can be applied to a precise thin film growth method and which can add carbon into a film at a precise addition ratio. Another object of the present invention is to provide a vapor deposition apparatus provided with an evaporation amount control mechanism that can produce a film to be produced with extremely small accuracy.

[0004]

A vapor deposition apparatus according to the present invention accelerates electrons emitted from a hot filament in a vacuum and deflects them by a magnetic field or an electric field to irradiate an evaporated substance as an electron beam and heat it. In the vapor deposition apparatus for evaporating by the above, the vaporized substance is carbon, and the crucible containing the carbon, the surface of the peripheral portion of the crucible, and the hearth portion for deflecting the orbit of electrons are each covered with a carbon material. To do. In the above configuration, preferably, the thermocouple in contact with the carbon material and the output of the thermocouple are input, and the power supply amount to the hot filament is controlled so that the output value of the thermocouple is maintained at a predetermined value. A control means is provided. Further, the vapor deposition apparatus according to the present invention is an vapor deposition apparatus for accelerating electrons emitted from a hot filament in a vacuum and deflecting the electrons by a magnetic field or an electric field to irradiate an evaporation substance as an electron beam, and heating and evaporating the same. Input the thermocouple in contact with the surface of the surrounding part of the crucible containing the vaporized substance and the output signal of this thermocouple, and supply the power to the hot filament so that the output value of the thermocouple is maintained at a predetermined value. It is characterized in that a control means for controlling is provided.

[0005]

In the vapor deposition apparatus according to the present invention, the surface of the crucible in which carbon, which is a vaporized substance, and the peripheral portion thereof, and the hearth portion are covered with the carbon material, so that carbon is added as an impurity in a predetermined film. At this time, impurities other than carbon can be prevented from being added, and the impurity concentration can be controlled with high accuracy. Therefore, the vapor deposition device according to the present invention can be applied to a precise thin film forming method, for example, a molecular beam epitaxy method. In addition, since the amount of evaporation of evaporative substances can be grasped via temperature using a thermocouple, an electron beam is given to the evaporative substance by using the detection value of the thermocouple so that the output of the thermocouple becomes constant. By controlling the amount of power supplied to the hot filament, the amount of evaporation can be controlled accurately.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, 1 is an electron gun type vapor deposition device,
2 is a hot filament. The vapor deposition device 1 has a crucible 3
And a recess 4 having a surface provided with the crucible 3 and hearths 5A and 5B forming walls on both sides of the recess 4. Inside the crucible 3, carbon 6 which is an evaporated substance is arranged. A carbon plate 7 is provided on each of the inner surface of the crucible 3, the recessed surface that is the peripheral portion of the crucible 3, and the inner surfaces of the hearths 5A and 5B so as to cover these surfaces. In the illustrated example, the carbon plate 7 is shown integrally, but in reality,
It is desirable to separately provide the carbon plate for the hearth surface and the carbon plate for the surface including the crucible.

The arrangement position of the hot filament 2 is set to a position at a predetermined distance from the vapor deposition device 1, and receives a predetermined electric power from the power source 8 to generate heat and generate thermoelectrons. The generated thermoelectrons are converged in a vacuum environment and irradiated as an electron beam 9 on the carbon 6 in the crucible 3. The electron beam 9 emitted from the hot filament 2 is changed by the device for changing the trajectory of the electron beam provided in the hearths 5A and 5B.
The orbit is controlled so that the carbon in the crucible 3 is effectively irradiated.

The carbon evaporated from the vapor deposition apparatus 1 by heating with the electron beam 9 advances upward in the state of vapor and vapor-deposits or forms a film on the surface of a substrate (not shown) located above the vaporization apparatus 1. Added in.

According to the above construction, the carbon plate 7 is configured to completely cover the crucible 3 formed of a metal substance other than carbon, the surface of the peripheral portion of the crucible 3 and the surfaces of the hearths 5A and 5B. Therefore, since the carbon material covers all the places where the primary electron beam and the reflected electron beam may collide, only carbon from the vapor deposition apparatus 1 will fly to the substrate to be vapor deposited. .. That is, it is possible to completely prevent the copper forming the crucible 3 and the like and the nickel forming the hearths 5A and 5B from being evaporated and mixed as impurities.

As another structure, as shown in FIG. 1, the thermocouple 1 is in contact with the surface of the carbon plate 7 near the crucible 3.
0 is placed. The thermocouple 10 measures the temperature of the carbon plate 7. The temperature of the carbon plate 7 is substantially the same as the temperature of the carbon 6 which is the evaporated substance. Therefore, the output signal of the thermocouple 10 is utilized to configure the control system shown in FIG.

In FIG. 3, the output of the thermocouple 10 is input to the control means 11. The control means 11 has a temperature setter 12. The temperature setter 12 gives a signal regarding the predetermined temperature T0 to the control means 11. This temperature setter 12
Provides a reference temperature for setting the vaporized material to a desired temperature. Assuming that the output signal of the thermocouple 10 represents the temperature T, the control means 11 takes the difference between the temperature T0 and the temperature T by the built-in comparison means. Control means 11
Controls the amount of power supply to the hot filament 2 in the power supply 8 based on the temperature difference so that the temperature difference becomes zero. By such a control system, carbon 6 which is an evaporated substance
However, temperature control is performed so that the temperature is always maintained at the temperature set by the temperature setter 12. When the temperature of the evaporation material is constantly set to a predetermined temperature, the amount of evaporation from the evaporation material is maintained at a constant value in proportion to the set temperature. As a result, the vapor deposition amount on the substrate can be controlled with high accuracy. In other words, the thickness of the film to be produced can be produced with extremely thin precision.

From another technical point of view, it is possible to precisely control the electron flow density of the electron beam 9 given to the carbon 6 from the hot filament 2 and thereby prolong the life of the main body of the electron gun type vapor deposition apparatus. be able to.

The evaporation amount control mechanism is not limited to the carbon-added type vapor deposition apparatus of the above-mentioned embodiment,
Of course, it can be generally applied to other vapor deposition devices.

[0014]

As is apparent from the above description, according to the present invention, impurities other than carbon are not mixed and the amount of evaporation can be controlled with high precision, so that the present invention can be applied to a precise thin film growth method such as a molecular epitaxy method. can do. Further, carbon can be added to the film at a precise addition ratio. Also GaA
A safe P-type doped semiconductor can be produced by a molecular beam epitaxy method such as s without using a poison such as beryllium. Further, since the temperature of the evaporation substance is directly measured using a thermocouple and the evaporation amount is controlled based on the temperature, the thickness of the vapor deposition film to be produced can be produced with extremely small accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a vapor deposition device according to the present invention.

FIG. 2 is a transverse cross-sectional view showing a main part of a vapor deposition device.

FIG. 3 is a block diagram showing a control system of an evaporation amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electron gun type vapor deposition apparatus 2 ... Thermal filament 3 ... Crucible 5A, 5B ... Hearth 6 ... Carbon (evaporated substance) 7 ... Carbon plate 8 ... Power source 9 ... Electron beam 10 ... Thermocouple 11 ... Control means

Claims (3)

[Claims] 1. An evaporation apparatus in which electrons emitted from a hot filament are accelerated in a vacuum and deflected by a magnetic field or an electric field to irradiate an evaporated substance as an electron beam, and the evaporated substance is heated and evaporated. The substance is carbon, and the vapor deposition apparatus is characterized in that the crucible containing the carbon, the surface of the peripheral portion of the crucible, and the hearth portion that deflects the orbit of electrons are covered with a carbon material. 2. The vapor deposition apparatus according to claim 1, wherein the thermocouple in contact with the carbon material and the output of the thermocouple are input, and the output value of the thermocouple is held at a predetermined value. A vapor deposition apparatus comprising a control means for controlling a power supply amount to the hot filament. 3. An evaporation apparatus in which electrons emitted from a hot filament are accelerated in a vacuum and deflected by a magnetic field or an electric field to irradiate an evaporated substance as an electron beam, and the evaporated substance is heated and evaporated. A thermocouple in contact with the surface of the surrounding portion of the crucible containing the substance and an output signal of the thermocouple are input, and power is supplied to the hot filament so that the output value of the thermocouple is maintained at a predetermined value. An evaporation apparatus comprising a control means for controlling the amount.