JPH0575828B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a thin film manufacturing apparatus employing, for example, the MBE (molecular beam epitaxial) method.

<Conventional technology> A thin film manufacturing apparatus using the MBE method is configured to obtain a thin film by epitaxial growth on the surface of a substrate by irradiating the surface of a sample such as a substrate with a molecular beam of a film forming material in a vacuum chamber. has been
In this type of apparatus, the crystallinity of a film has conventionally been monitored during film formation using the RHEED (reflection high energy electron diffraction) method.

This RHEED method irradiates the thin film formation surface of the substrate with an electron beam during film formation, and captures the diffracted reflected electron beam that is diffracted or reflected by the thin film formation surface with a fluorescent screen, and the beam that appears on the screen. A method of observing periodic changes in the light intensity of the brightest spot in the pattern (generally called the specular beam).
By observing the RHEED vibration, it is possible to monitor the quality of the crystallinity of the film being formed.

<Problems to be Solved by the Invention> By the way, the area that can be observed using the RHEED method is approximately several hundred Å square at most, and conventionally, it has been impossible to monitor crystallinity over a wide range of the entire film during film formation. It was possible. Further, according to conventional thin film manufacturing apparatuses, RHEED vibration is not used to actively control the crystallinity of the film.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film manufacturing apparatus that allows crystal growth to proceed normally over the entire surface of a substrate during the film forming process, and that can obtain a thin film with good crystallinity. .

<Means for Solving the Problems> The configuration for achieving the above object will be explained with reference to FIGS. 1 and 2 corresponding to the embodiment. By irradiating the surface of the sample S with evaporated particles of the film material,
In the apparatus that forms a thin film on the surface of the sample S,
During film formation, in order to change the electron beam source (electron gun) 6 that irradiates the thin film formation surface of the sample S with an electron beam from a predetermined direction and the irradiation position of the electron beam on the thin film formation surface,
A scanning means for scanning the electron beam (for example, the deflection magnet 7) and at least two electron beam irradiation positions on the thin film forming surface of the sample S (for example, points A, B, and C).
beam intensity measuring means (e.g., fluorescent glasses 8a, 8b, and 8c, and photomultiplier tubes 9a, 9b, and 9c) for individually and momentarily measuring the intensity of each diffracted reflected electron beam, and based on each measurement value. control means for determining the intensity of each vibration, and changing the conditions for irradiating the surface of the sample S with the evaporated particles during film formation in order to eliminate the phase difference when there is a phase difference between the vibrations. (for example, shutters 4 and 5 equipped with drive control devices 4a and 5a and a computer 11 that controls them).

Here, the control means may be means for controlling the collision energy of the evaporated particles with the sample S, etc.

<Function> By scanning the electron beam, it becomes possible to monitor the crystallinity at, for example, three different locations on the thin film forming surface of the substrate S, points A, B, and C.

Here, during film formation, for example, each point A on the substrate S,
If the progress state of the crystal growth in B and C is different, for example, as shown in FIG. 3, a shift occurs in the phase of the intensity oscillation of each of the diffracted reflected electron beams in A, B, and C. When such a phase shift occurs, the control means changes the lamination process on the surface of the substrate S by, for example, closing only the shutter 5 for a predetermined time,
Next, for example, control is performed such as closing only the shutter 4 for a predetermined period of time to change the lamination process, and by repeating such control in a trial and error manner until the phases of each vibration match each other, the substrate The progress state of crystal growth at each point A, B, and C of S can be made uniform.

<Example> Examples of the present invention will be described below based on the drawings.

Fig. 1 is a longitudinal sectional view of the film forming function section of the embodiment of the present invention and a block diagram of its control system.
The figure is a cross-sectional view taken along the - arrow direction of the film forming function section, and shows an example in which the present invention is applied to an apparatus using the MBE method.

Two evaporation sources 2 and 3 that generate molecular beams of a film-forming material are arranged in a vacuum chamber 1.
The molecular beams from the evaporation sources 2 and 3 are configured to both reach the same substrate S surface.

A drive control device 4a is provided between the evaporation source 2 and the plate S.
A shutter 4 having a Intermittent progression can be controlled. Similarly, a shutter 5 including a drive control device 5a is disposed between the evaporation source 3 and the substrate S.

On the other hand, on the side of the vacuum chamber 1, an electron gun 6 is provided that can irradiate the thin film forming surface of the substrate S with an electron beam from a predetermined direction. This electron gun 6 is provided with a deflection magnet 7. The deflection magnet 7 is excited by a magnet power supply 7a driven in response to a command signal from the computer 11, and the deflection magnet 7 directs the electron beam at a predetermined period within a range on the thin film forming surface of the substrate S. , for example, scans two-dimensionally at a period of 100 ms.

Diffraction that is diffracted or reflected at three points A, B, or C on the thin film forming surface of the substrate S is reflected by fluorescent glasses 8a, 8b, and 8c coated with a fluorescent agent, respectively, in the traveling direction of the reflected electron beam. It is arranged. Each of the fluorescent glasses 8a, 8b, and 8c generates light according to the intensity of the electron beam when it is incident thereon. In addition, each fluorescent glass 8a, 8b, 8
c may be large enough to capture only the specular spot of the diffracted and reflected electron beam.

At the rear of each fluorescent glass 8a, 8b and 8c, optical fibers 9a, 9b and 9c are provided in close proximity to their respective light emitting surfaces, so that the light generated in each fluorescent glass 8a, 8b and 8c is are transmitted by respective optical fibers 9a, 9b, 9c to photomultiplier tubes 10a, 10b and 10c, respectively.

Each photomultiplier tube 10a, 10b and 10c
converts the transmitted light into an electrical signal and outputs it. Each output is sent to an A/D converter 12a,
The data is taken into the computer 11 via 12b or 12c.

In addition to controlling the drive of the magnet power supply 7a described above, the computer 11 also controls each photomultiplier tube 10a,
The intensity oscillations of the diffracted and reflected electron beams are calculated based on the electric signals from 10b and 10c, and each shutter 4
and 5, and is configured to output control signals regarding opening and closing of the drive controllers 4a and 5 to their respective drive control devices 4a and 5a.

During film formation, the progress state of crystal growth at each point A, B, and C on the substrate S is different, for example, as shown in FIG. When a phase shift occurs in the vibrations, the computer 11 may, for example, first control the shutter 5.
Then, only the shutter 4 is closed for a predetermined time to control the lamination process on the surface of the substrate S.
Such control is repeated by trial and error until the phases of the intensity oscillations at each point A, B, and C match each other. As a result, each point A, B,
In other words, crystals can be grown uniformly over almost the entire surface of the substrate S.

It goes without saying that crystal growth can be controlled more precisely by increasing the number of monitoring points on the thin film forming surface of the substrate S.

The above describes an example in which the present invention is applied to a thin film manufacturing apparatus using the MBE method, but the present invention is not limited to this, and the present invention may, for example, ionize evaporated particles, accelerate the ions, and irradiate the substrate surface. It is also applicable to devices that form thin films by. In this case, the ionization rate of the evaporated particles or the acceleration thereof may be controlled.

<Effects of the Invention> As explained above, according to the present invention, during the film formation process, the thin film formation surface is irradiated with an electron beam and scanned, and the intensity of the diffracted reflected electron beam from multiple parts of the thin film formation surface is adjusted. is measured moment by moment, and if there is a phase shift of each intensity vibration based on these measured values, the film lamination conditions are changed during film formation in order to eliminate the phase shift. As a result of making it possible to make the crystal growth signal state uniform over the entire surface of the sample, a thin film with good crystallinity can be obtained. Moreover, since the thin film itself to be put into practical use is monitored during the film formation process and the lamination conditions are controlled, the yield is extremely high.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the film forming function section of the embodiment of the present invention and a block diagram of its control system.
The figure is a sectional view taken along the - arrow of the film forming function section of the example. FIG. 3 is a diagram for explaining the operation of the present invention. 1... Vacuum chamber, 2, 3... Evaporation source, 4,
5...Shutter, 4a, 4b...Shutter 4, 5
drive control device, 6...electron gun, 7...bending magnet, 8a, 8b, 8c...fluorescent glass, 10
a, 10b, 10c...photomultiplier tube, 11...
computer.

Claims (1)

[Claims] 1 In an apparatus that forms a thin film on a sample surface by irradiating the sample surface with evaporated particles of a film-forming material in a vacuum chamber, an electron beam is applied to the thin-film forming surface of the sample from a predetermined direction during film formation. an electron beam source for irradiating the electron beam, a scanning means for scanning the electron beam in order to change the irradiation position of the electron beam on the thin film formation surface, and diffraction at at least two positions of the electron beam irradiation position on the thin film formation surface. A beam intensity measurement means that measures the intensity of each reflected electron beam individually and moment by moment, and oscillations of each intensity are determined based on each measurement value, and if there is a shift in the phase of each oscillation, the phase is determined. A thin film manufacturing apparatus comprising a control means for changing the conditions for irradiating the sample surface with the evaporated particles during film formation in order to eliminate the deviation.