JPS63145767A - Sensor for monitoring vapor deposition - Google Patents

Abstract

PURPOSE:To prevent degradation in monitoring accuracy by the light of a filament for generating an electron beam, by providing a magnetic field to the passage of the electron beam at the time of monitoring the light emitted by the electron beam of the flow of a material to be evaporated for vapor deposition in a vacuum deposition device. CONSTITUTION:This monitoring sensor 10 for vacuum deposition monitors a vapor deposition speed by casting the electron beam (e) generated from the filament 25 to the metal vapor flow 20 in the vacuum deposition device, taking the emitted light specific to said vapor out of a hole 22 and converting the same to an electric signal by a photodetector. The magnetic field B orthogonal with the electric field between the filament 25 which is the cathode of such sensor and an anode 27 for accelerating the electron beam (e) is formed of a magnet 3 to curve the route of the electron beam (e). viewing of the light from the filament 25 from a place where the electron beam (e) bombards the material to be evaporated and generates the emitted light is thereby prohibited and the accuracy of the above-mentioned photodetection signal by the light of the filament is improved.

Description

Detailed Description of the Invention (Industrial Application Field) This invention is a vacuum evaporation method that detects electron impact light generated by evaporated matter excited by electron impact without being bothered by noise. Regarding monitoring sensors.

(Prior art) An example of an apparatus for measuring the evaporation rate by exciting the evaporated material by bombarding it with electrons and detecting the intensity of the electron impact light generated when the excited evaporated material returns to a metastable state is shown in FIG. (U.S. Pat. No. 4,036,167).

The EIE S (Electron
Impact Emission 5pect
The sensor 10 exhibits the shape of a rectangular parallelepiped, and includes a bottom plate 12, a corresponding top plate (removed to show the inside), and two opposing side plates 14, 15 (1
5, most of which have been removed to reveal the interior). The bottom plate 12 and the top plate are provided with a vapor flow path 20 for passing a portion M of the evaporated matter to be monitored. is provided.

The side plate 15 is provided with a hole 2 for providing an optical path perpendicular to the steam flow M passing through the steam flow path 20.

The excitation electron beam e is generated by heating the filament 25 shown at the right end of FIG. They are accelerated to produce relatively low energy electrons. The anode 27 is disposed in a portion of the end plate 6 on the other side of the steam flow path 20,
The excitation electrons e generated by the filament 25 are configured to travel across the vapor flow M.

Positively charged focusing electrodes 28, 29 are arranged in the electron beam path e to form an excitation beam with a restricted shape.

The steam flow M that has passed through the steam flow path 20 passes through the filament 25
, focusing electrodes 28 and 29 are used to generate and accelerate the excitation electrons e, and when the excited electrons return to a metastable state, the light emission p peculiar to the substance of the vapor is emitted from the hole 22. It is taken out to the outside through. The extracted light p passes through an optical filter or a monochromator, and then is converted into an electrical signal by a photodetector such as a photomultiplier, and is used for monitoring and controlling the deposition rate.

(Problems to be Solved by the Invention) Since the conventional vacuum evaporation monitoring sensor configured as shown in FIG. 2 uses a high-temperature filament 25 as the cathode, the light emission of the filament itself is superimposed on the light emission of the vapor. When the luminescence p of the vapor is weak, the luminescence p
This has the disadvantage that it is buried in the noise and cannot be detected.

For example, in MBE equipment, GaAs, InP, InGaAs
When forming a thin film of an m-v group such as P, or an n-VI group such as Zn5e, ZnS, etc., a four-atom molecular beam is generated for the V group, and a diatomic molecule is generated for the ■ group.

For example, when a molecular beam of As is generated, the light emitted from the molecule is on the long wavelength side of 300 nm or more.

Now, when I plotted a graph of the measured values of the light emission of the As molecular beam using a conventional sensor for monitoring vacuum evaporation using a hot filament, it turned out to be a curve like that shown in Figure 3. Analysis revealed that the intensity of light with a wavelength of 300 nm or more is 10% of the expected luminescence amount of As vapor.
It was almost 0 times. This is clearly because the light emission from the filament was superimposed. Naturally, the light emitted from As was completely buried in it and could not be detected.

(Objective of the Invention) The purpose of the present invention is to provide a monitoring center for vacuum evaporation that can remove noise caused by filament light emission and stably detect vapor emission even when the vapor emission is weak. do.

(Means for Solving the Problems) The present invention provides a method in which the electrons emitted from the cathode travel toward the anode and are placed between the anode and the cathode in at least a part of the electron beam path until they impact the evaporated matter. Set the magnetic field orthogonal to the electric field.

(Function) By passing the electron beam through the magnetic field set as above, the electron beam path is curved sharply, and from the place where the electrons impact the evaporated material and generate light emission, the electron beam is passed through the filament of the electron source. to prevent noise from being mixed in from the source.

(Example) Next, the present invention will be explained in detail by way of an example using figures.

2A and 2B are a plan sectional view and a front view of FIG. 2, and correspondingly, embodiments of the present invention can be shown as in FIGS. 1A and 1B. . Identical members are designated by the same reference numerals, and therefore their explanations will be omitted.

In this embodiment, a magnetic field B is applied using a magnet 3 in a direction perpendicular to the electron beam, ie, the electric field.

30 is a yoke that connects the two magnets 3. Because of this magnetic field, the electron beam takes a curved path as shown in the figure, and from the emission point where the electron beam e intersects the evaporator M,
The filament 25 is hidden and cannot be seen. Therefore, the conventional problem that the light from the filament 25 is mixed into the emitted light p and detected as noise is eliminated.

Curve B in FIG. 3 is a graph of the measured values of the light emission of the As molecular beam, which was measured using the apparatus of this example under the same conditions. The filament was emitting noise 3
It can be seen that because the light of 0.00 nm or more disappeared, the light emitted from the As vapor escaped the burial and appeared and was clearly recorded.

Similar good results were obtained for evaporated substances other than As.

(Effects of the Invention) Since the present invention has the configuration and operation as described above, noise caused by light emission of the filament is removed,
Provided is a vacuum deposition monitoring center that can stably detect vapor emission even when the vapor emission is weak.

[Brief explanation of the drawing]

FIG. 1A is a plan sectional view of one embodiment of the vacuum deposition monitoring sensor of the present invention. FIG. 1B is a front view thereof. FIG. 2 is a perspective view of a conventional vacuum deposition monitoring sensor. Figures 2A and 2B are similar to the first figure [JA,B]. FIG. 3 is a graph of measured values of light emission of molecular beams of As, where curve B is that of the device of the present invention and curve A is that of the conventional Ha
Show things. 10...Sensor, 12...Bottom plate, 14.1
5...Side plate, 16.17...End plate, 20...
Steam flow path, 22... Hole, 25... Filament, 28.29... Focusing electrode, 30... Yoke,
3... Magnet, e... Electron beam, M... Evaporated matter, p... Luminescence. Patent Applicant Nichiden Anelva Co., Ltd. Agent Patent Attorney Kenji Murakami 41 Nine Steps - Tongue [mw]

Claims (1)

[Claims] (1) Monitoring of vacuum evaporation configured to measure the evaporation rate of the evaporated material by detecting the emission intensity of electron impact light generated when the evaporated material excited by electron impact returns to a metastable state In the sensor, from the cathode that generates electrons to bombard the evaporated matter
Vacuum evaporation characterized in that a magnetic field orthogonal to the electric field between the anode and the cathode is set in at least a part of the electron beam path from where the electrons travel toward the anode to the region where the evaporated material is irradiated. monitoring center.