JPS61104075A - Device for controlling ionizing vaporization velocity - Google Patents

Abstract

PURPOSE:To obtain the titled device capable of supplying a requisite amt. of particles to the surface to be vapor-deposited by ionizing vaporized particles from a vaporization source for making a vapor-deposited thin film with a flow of thermoelectrons, controlling the vaporization velocity by using a part of the ion current, and keeping the vaporization velocity constant. CONSTITUTION:A vaporization substance 4 in a vaporization source 5 is heated by an electron gun 6 and a control electric power source 15 in a bell jar 1 which is made vacuous by an evacuation system 2, and vaporized at a constant velocity. The whole vaporized particles are ionized in a specified ratio and uniformly with a flow of thermoelectrons from the filament 7 of a thermoelectron emitting electrode provided at a position where the particles pass, and vapor-deposited on a sample 3 by opening a shutter 8. In the vacuum vapor- deposition thin film forming device, the ions in the vicinity of electrode 7 is made into an ion current by the electrode 7, the current is detected by an ammeter 12, and the amt. of vaporization substance 4 to be vaporized is automatically controlled by the control electric power source 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for coating the surface of a sample with a thin film in vacuum by ionizing evaporated particles as a method of keeping the evaporation rate constant and determining the thickness of the film by increasing the deposition time. death,
This invention relates to a device that uses a flow of ions to maintain a constant evaporation rate.

Conventional methods for controlling the thickness of a thin film include a method of determining the thickness from the deposited film and a method of determining the thickness of the film based on the deposition time while keeping the evaporation rate of the evaporation source constant. The former is commonly used, such as a crystal film thickness meter or an optical interference film thickness meter, but the electrical signal obtained as the film thickness is not the evaporated atoms or molecules themselves, but the film thickness converted by the frequency or light from the instrument's detector. It is. This method does not control the six atoms themselves and cannot determine the state when a thin film is formed. In addition, the detector has the disadvantage of requiring replacement.In recent years, it has been known that the process of thin film formation has a large effect on crystal growth and all performance, so the latter method is recommended. is required to be produced.

The latter method includes a sputtering method using a Benifugu discharge and a method of measuring using an ion current generated during vacuum evaporation. The sputtering method involves sputtering in a strong magnetic field, resulting in the deposition of only expensive, neutral particles.

In addition, in the method of using the ion current generated during evaporation, the ion current generated is very small at 1a''6 to 1 (r'7 ampere), so it is difficult to automatically control the evaporation rate due to problems such as discharge that occur in a vacuum. The law is impossible to put into practice.

In the method of ionizing particles evaporated from an evaporation source by irradiating them with thermal electrons according to the present invention, an ion current of several tens of amperes can be obtained even in a high vacuum. Furthermore, there is no problem caused by vacuum discharge, and by using a portion of this ion current, it is possible to easily manufacture a device that can keep the evaporation rate of the evaporation particles of the evaporation source constant.

Condition 11 necessary for producing a vapor-deposited thin film is to control the temperature and surface polish of the vapor-deposited surface. The temperature of the evaporation surface cannot be controlled to be constant when high-temperature evaporated particles are flying in without limit, so it is necessary to keep the evaporation rate constant and supply the required amount of particles to the evaporation surface. Since impurities and the like serve as nuclei for forming crystals, the surface is free from impurities and a different metal is supplied as necessary. In this case, the bond between metals is more like an ion/metal than a thermally vibrating layer of atoms.
Since the bonding energy is higher in the state of , it is thought that it is more effective for the production of compounds or alloys having iono bonds to have particles in the io/ state.

The present invention creates a device that has a certain relationship between the ion current and the evaporation particles by uniformly ionizing the evaporation particles at a certain ratio or by ionizing all of the evaporation particles, and uses a part of the ion current to create an evaporation source. The evaporation rate of the evaporated particles was kept constant. Its use is based on the ion blating/deposition method (PAT Application No. 57-1
51892), a method of forming a single crystal on a vapor deposition surface by being able to more accurately control the temperature of the vapor deposition surface, and a method of forming a compound by changing the ratio of ions of a plurality of evaporated particles. Also, creating a compound by changing all of the electrons (FAT application 5)
8-048359 and 58-063209), and is essential for producing materials with new functions.

The details of the present invention will be explained below with reference to the drawings.

Figure 1 shows a block diagram schematically explaining the apparatus of the present invention, in which 1 is a vacuum container, 2 is an exhaust system for creating a vacuum, 3 is a sample for which a thin film is to be deposited, and 4 is for evaporation. 5 indicates a plurality of furnaces for vaporizing various types of substances; 6 indicates an electron gun; 7 indicates a thermionic emission electrode filament having a circular structure J6 for uniformly or completely ionizing the evaporated particles;
The eyelid/door has a structure in which thermoelectrons are kept constant by a control power source 17 via a transformer 16. In the first figure, li
Electric @17 uses a highly accurate constant voltage regulator. What evaporated from evaporation furnace 5? When T4 passes through the center of the electrode filament 7 which emits electrons for ionization, it is ionized by the electrons and most of the ions reach the deposition sample as is. Also, the io/ formed near JJi7 reaches the electrode 7 and becomes an ion? The structure is such that the current becomes an If current and the whistle of evaporation is read by the ammeter 12. Since the control power source 15 automatically controls the indication of the ammeter 12 to a predetermined value, the evaporation rate of the evaporated substance 4 is constant. The evaporated particles 4 are deposited on the sample 3 by polishing the gloss 7 tar 8. The relationship between the amount of evaporation and time is calculated by measuring in advance with a evaporation film thickness measuring device 10.11. , the ammeter 18 determines the ratio of electrons and ions deposited on the sample 3, and the resistor 2
This is a regulator that arbitrarily determines the ratio depending on the combination of 0 and battery 21.

FIG. 2 shows a curve (expressed in ml) of the current flowing through the ammeter 12 when the apparatus shown in FIG.

The horizontal axis indicates the elapsed time of the operation. (A1 shows the state in which the power is first turned on to 17 and thermionic electrons are irradiated from the electrode 7.Next, when the control power source 715 is activated, the evaporated matter 4 is evaporated and the central part of the thermionic emission electrode 7 When it passes through, it becomes ion and most of it reaches the deposition substrate 3.Also, a part of ion reaches the electrode 7 and flows into the ammeter 12, and the control power supply 15 is operated until it reaches the set value of this ammeter, and the ion reaches the evaporation substrate 3. It remains constant in the state.

Figure 3 shows the structure of the thermionic emitting electrode eyelet/door viewed from above. 71 and 72 are electrode rings for supplying power to the eyelet/door, and 72 electrostatically emits thermionic electrons to the center side. It has a semicircular structure in order to direct it towards the target. +73 is 71
, 74 is the electrode of 72, 75 is insulating glass, 76 is an electrode for extracting thermoelectrons from the filament, and a power source 13 is connected between the filament 7 and the electrode 76 through an ammeter 12.
is connected. Electrode 76 is grounded. 16 indicates a transformer that supplies power to the filament 7.

Figure 4 is shown in Figure 3! The density of thermionic electrons in the cross section xx' at the center of the pole and the density of evaporated particles passing through the cross section xx' from the evaporation source are shown. The fd1 curve shows the density of hot electrons and has a structure that always provides a constant current6(c)
The curve shows the density of evaporated particles, which increases or decreases depending on the amount of evaporation.

Firano here/from the door? Electrons irradiated toward the center of the l1m pole evaporate and collide with particles passing through (
or absorption) and ejects electrons, and the particle becomes an iono. - It is known that blue electrons increase each time they collide, causing an electron avalanche, and ionizing a certain percentage or all of the evaporated particles. In this method, if the structure and vacuum pressure do not change, the amount of evaporated particles can be measured by measuring the ion current, so some of the total ions flow into the filament 7 and the surrounding 7rLNi.
Evaporation rate can be controlled by measuring and controlling with [.

As explained above, the present invention has the following characteristics in that it is possible to automatically control the evaporation rate of the evaporation source using a means of ionization, which has been difficult in the past.

■The temperature of the sample can be kept constant. ■It is possible to create deposited films with different components.

Also, @ amount can be added to the sample. ■The initial conditions for vapor deposition can also be controlled. ■Vapor deposition is ionic. ■It can be deposited in the same way even in high vacuum. ■The detector is resistant to dirt in a vacuum and can be used semi-permanently. ■Ionization differs depending on the substance, but it can be deposited in the same way by changing the sensitivity of the amplifier. ■ Film thickness can be controlled in 7 minutes. ■Good reproducibility. @Easy to connect to computer.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, FIG. 2 is a control curve diagram for explaining the operation, and FIG.
The figure is a configuration diagram of the thermionic emission electrode in the same example, and Figure M4 is a characteristic curve diagram showing the density of evaporated particles and the density of emitted thermionic electrons in the xx' cross section in the center of Figure 3. . 1. Pelger, 2 Exhaust system, 3.・
sample, 4 substance, 5 electrode, 6 electron gun,
7.・Filame 7), 8/Yatter,
9 Heater, 10 My, thickness gauge, 11 Film thickness meter, 12 Ammeter, 13 - Battery, 14.
...Transformer, 15 Control TL source, 16 Transformer, 17 Control power supply, 18. - IT ammeter 19 ・Diode, 20 ・Variable resistor, 21
・? IIC pond, 22...Power supply, 71 Electrode/G, 72 Electrode S/G, 73TL pole, 74.
- TL pole, 75...insulator, 76 positive TL pole

Claims (2)

[Claims] (1) In a vacuum evaporation thin film production device that heats and evaporates a substance in a vacuum to create a thin film, the material that evaporates from the evaporation source always has a constant film thickness over time, and the particles that evaporate from the evaporation source At the position where the evaporated particles pass, an electrode is provided that emits a constant thermionic current for the purpose of ionizing the evaporated particles uniformly or all of them, and ionizes the evaporated particles.
An ionization evaporation rate control device that uses a portion of the ion current to maintain a constant evaporation rate. (2) In the ionization evaporation rate control device shown in (1), the thermionic emission electrode is made circular (see Figure 3), and thermionic electrons emitted by the filament and thermionic extraction electrode fly to the center and evaporate from the evaporation source. An ionization evaporation rate control device that has a structure that always ionizes a certain percentage or all of the evaporated particles by having an electron density that matches the distribution density of the particles.