JPH0432142A - Crystal surface observation device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a crystal surface observation device used for analysis and evaluation of crystal surfaces.

(Prior Art) FIG. 3 shows the configuration of a conventional crystal surface observation apparatus using high-energy electron diffraction.

In the figure, 1 is a high-energy electron gun, 2 is a crystal sample to be observed, 3 is a fluorescent screen, and 4 is a high vacuum chamber. The detailed structure of the fluorescent screen 3 is shown in FIG. In the figure, 5 is lead glass that blocks radiation, 6 is a grounded conductive film that releases arriving electrons to the ground, and 7 is a phosphor film that emits visible light when electrons with energy above a certain level collide with it.

The electron beam accelerated and focused by the electron gun 1 is reflected and diffracted once by the sample 2, and then reaches the fluorescent screen 3. By measuring the emission intensity distribution of the phosphor film 7 on the screen 3 and its time change, the angular distribution and time change of the intensity of the electron beam reflected by the crystal surface can be measured. The intensity of the electron beam reflected by the crystal surface is highly sensitive to the state of the crystal surface. The crystal surface observation device described above utilizes this property and has a function of observing the surface state of the crystal from the emission intensity on the screen.

(Problems to be Solved by the Invention) In the crystal surface observation device described above, the intensity of the reflected electron beam is indirectly determined by the emission intensity of the phosphor film 7. The emission intensity of the phosphor film 7 and the intensity of the incident electron beam do not have a perfect linear relationship, and in order to measure the emission intensity, a separate measurement system with new nonlinearity and noise is required. This device has a problem in that it is not possible to quantitatively determine the angular distribution and time change of the reflected electron beam intensity.

The present invention has been made to solve the above problems.

An object of the present invention is to provide a quantitative crystal surface observation device that does not have any of the factors that cause nonlinearity or noise as described above, by measuring the intensity of the electron beam itself that has reached the fluorescent screen 3 as a current. be.

(Means for Solving the Problems) In order to achieve the above object, the present invention irradiates a crystal surface with a high-energy electron beam from an electron gun in a high vacuum, and emits the electron beam that is reflected and diffracted by the crystal surface. In a crystal surface observation device that observes the state of a crystal surface by detecting it with a fluorescent screen located axially symmetrical to the electron gun with respect to an axis perpendicular to the surface, an electrode is attached to the conductive film of the fluorescent screen that detects the electron beam. The gist of the invention is a crystal surface observation device characterized by observing the state of a crystal surface by providing a current detection system between an attached electrode and ground.

(Function) In order to achieve the above-mentioned object, the present invention disconnects the conductive film of a fluorescent screen that detects reflected electron beams from the ground, and measures the current flowing between the electrode attached thereto and the ground. Its main feature is to measure electron beam intensity.

That is, instead of measuring the reflected electron beam intensity indirectly by the emission intensity of the phosphor, the electron beam intensity itself is measured as a current, so it is possible to quantitatively measure the reflected electron beam intensity.
Furthermore, it has the effect of making it possible to observe the crystal surface in detail.

(Example) Next, an example of the present invention will be described. Note that the embodiments are merely illustrative, and it goes without saying that various changes and improvements can be made without departing from the spirit of the present invention.

FIG. 1 shows a structural diagram of an embodiment of a fluorescent screen and measurement system according to the present invention. In Figure 1, 8 is lead glass;
9 is a conductive film insulated from the ground, 10 is an electrode connected to the conductive film 9, 11 is a phosphor film, and 12 is an ammeter connected between the electrode 10 and the ground.

The electrons that have reached the screen flow from the electrode 10 through the ammeter 12 to ground. Thereby, in this embodiment, the electron beam intensity is directly measured by the ammeter 12. As a result, it becomes possible to quantitatively measure the reflected electron beam intensity, which is impossible with conventional techniques. Furthermore, since a measuring system for measuring the luminescent intensity of the phosphor, which was conventionally necessary, is not used, the signal-to-noise ratio is improved by more than one order of magnitude.

Although the conductive film on the fluorescent screen was not divided in the above example, it is also possible to measure the angular distribution of reflected electrons by dividing the conductive film into small pieces and extracting the current from each part. FIG. 2 is a diagram showing the structure of an embodiment in which the conductive film is divided, in which ■ is an electron gun, 2 is a crystal sample, 4 is a high vacuum chamber, 13.
, 14 and 15 are electrically independent conductive films. By separately measuring the currents flowing from the conductive films 13 and 14.15 to the ground, it is also possible to measure the angular distribution of the reflected electron beam. Further, in the above embodiment, a phosphor film 11 coated on the conductive film 9 was used, but the role of this phosphor film 11 is not essential to the present invention.
It is also possible to use a screen that is not coated with a phosphor film.

(Effects of the Invention) As described above, according to the present invention, in a crystal surface observation device, an electrode is attached to the conductive film of a fluorescent screen for detecting an electron beam, and a current detection system is provided between the electrode and the ground. The intensity of the electron beam that is reflected and diffracted at the surface can be quantitatively measured, which has the effect of enabling more detailed analysis and evaluation of the crystal surface.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of an embodiment of the fluorescent screen and measurement system according to the present invention, Fig. 2 is a diagram showing an embodiment in which the conductive film is divided in the present invention, and Fig. 3 is a diagram showing the structure of an embodiment of the fluorescent screen and measurement system according to the present invention. A structural diagram of a crystal surface observation apparatus using line diffraction. FIG. 4 shows a structural diagram of a conventional fluorescent screen used in this crystal surface observation apparatus. l...High energy electron gun 2...Crystal sample 3...Fluorescent screen 4...High vacuum chamber 8...Lead glass 9...Conductivity Membrane 10... Electrode 11... Phosphor film 12... Ammeters 13-15... Electrically independent conductive film box 1 Figure 2 Patent applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] A high-energy electron beam is irradiated onto the crystal surface from an electron gun in a high vacuum, and the electron beam reflected and diffracted by the crystal surface is transmitted to a fluorescent screen located axially symmetrically to the electron gun with respect to an axis perpendicular to the crystal surface. In a crystal surface observation device that observes the state of the crystal surface through detection, the state of the crystal surface is observed by attaching an electrode to the conductive film of the fluorescent screen that detects the electron beam and providing a current detection system between the electrode and ground. A crystal surface observation device characterized by: