JPH06103948A - Sample inclining operation method for transmission type electron microscope - Google Patents

Abstract

PURPOSE:To simplify the sample inclining operation by finding the relation of the initial crystal bearing and the standard bearing of the sample observing position from the rotating angle of a rotation mechanism, calculating the rotating angle to the object bearing from the above relation of bearings, and operating the sample inclining. CONSTITUTION:In the inclining operation method of a sample by a biaxial sample rotating mechanism, the relation of bearings between the initial bearing of the crystalline sample and the standard bearing is found from the rotating components of the electric motors of the biaxial sample rotating mechanism. Then, the rotating components of the biaxial sample rotating mechanism in order to incline the sample to the object crystal bearing is found by a calculator from the relation between the initial bearing, the standard bearing, and the object bearing, and by driving the biaxial sample rotating mechanism simultaneously as the rotating components, the sample is inclined. As a result, a desired sample inclining is carried out in a short time, and the sample inclining operation can be carried out simply in a series of operations of a transmission type electron microscope. Consequently, a diffraction image observation of sample, and the operating efficiency to observe a sample in such a condition can be improved more efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample tilting operation method for a transmission electron microscope having a biaxial sample tilting mechanism excellent in operability.

[0002]

2. Description of the Related Art In observation with a transmission electron microscope, a thin sample such as a thin film sample or an extracted replica sample through which an electron beam can be transmitted is prepared, mounted on a sample holder, and placed in the body of an electron microscope. After that, the observation position of the sample is moved to a position where the electron beam is transmitted, and the image formed on the fluorescent plate or the like by the electron beam transmitted through the sample is observed. The sample holder used in the transmission electron microscope is described, for example, in a document (Shigeo Sakata: “Technology of Electron Microscope”, Asakura Shoten 1982, p. 19).

Usually, in observation, even at the same observation location, the contrast of the image differs depending on the relationship between the direction of the electron beam and the orientation of the specimen, so it is necessary to incline the specimen in various directions for observation. In particular, when observing a crystalline sample, while observing the diffraction pattern and transmission image obtained by the diffraction phenomenon of the crystal, the sample is tilted to a desired crystal orientation by a sample tilting device having a uniaxial or biaxial rotation mechanism. , Observe the transmission image and diffraction pattern under the inclined condition. In that case, the diffraction pattern showing the crystal orientation of the sample and the observation of the transmission image under the tilted state, that is, the crystal diffraction condition are alternately performed. In order to obtain a clear contrast of the transmitted image and clarify the correspondence with the diffraction condition in this way, the inclination of the sample is essential. In this sample tilting method, in the conventional technique, the sample holder is rotated by only one axis, or the two-axis rotating mechanism of the sample is controlled by two separate operation devices, and the sample is tilted by each rotating mechanism. Was there.

In the case of a tilting device having a uniaxial rotating mechanism, the rotating axis is generally perpendicular to the longitudinal direction of the transmission electron microscope, that is, the direction of the electron beam, and the sample orientation is changed in the direction perpendicular to the rotating axis to form an image. Can be observed. The tilting device of the sample holder having the biaxial rotation mechanism can be tilted in any direction. As the two-axis rotation method, there are a sample tilting device having a rotating shaft in the direction of the electron beam and a rotating shaft perpendicular thereto, and a sample tilting device having two rotating shafts substantially perpendicular to the direction of the electron beam. For example, in the latter case, a rod-shaped sample holder is inserted laterally with respect to the longitudinal direction of the mirror body of the transmission electron microscope. The tilting of the sample using this sample holder is performed in the longitudinal axis (X
Rotation around the axis) and the axis perpendicular to the sample holder (Y
It is carried out by two rotating mechanisms of rotation about an axis.
At this time, the rotation directions of the X-axis and Y-axis rotation mechanisms need to be changed in both directions. Therefore, in order to rotate the motor in both directions around the X-axis and the Y-axis, the conventional technique has adopted a method of driving two electric motors using control switches that rotate in the respective directions.

[0005]

However, when the sample is operated by the conventional technique for operating the sample by the sample tilt operation method having the uniaxial rotation mechanism, the direction of rotation of the sample is limited and the orientation of the sample is poor in selectivity. I was only able to get the correct bearing. In addition, although the sample tilt can have any orientation in the sample tilt having the biaxial rotation mechanism, in the conventional sample tilt operation method, the two electric motors of the rotation mechanism are operated separately and rotated. That is, in the conventional technique, the X axis,
Since the transmission image and the diffraction pattern of the sample were observed while operating the two electric motors with respect to each rotation direction and the degree of rotation about the Y axis, a series of operations required skill. In particular, these conventional methods lack simplicity when observing the sample while checking the diffraction pattern of the sample to obtain a desired crystal orientation.

The present invention overcomes the problem of operability of rotation by two electric motors in a biaxial sample tilting device,
An object of the present invention is to provide a sample tilting operation method that simplifies the sample tilting operation in a series of operations of a transmission electron microscope.

[0007]

In order to solve the above-mentioned problems of the prior art, the present invention provides a method for tilting a sample for a transmission electron microscope by a biaxial sample rotating mechanism, in which an initial orientation and a reference of a crystalline sample are used. The azimuth relationship of the azimuth is obtained from the rotation components of the respective motors of the biaxial sample rotation mechanism, and then the rotation component of the biaxial sample rotation mechanism for inclining the sample to the target crystal orientation is the initial azimuth, A method for tilting a sample of a transmission electron microscope, characterized in that the sample is tilted by calculating the relationship between a reference direction and a target direction by a computer, and simultaneously driving the biaxial sample rotating mechanism by the rotation component thereof. .

[0008]

The present invention will be described in detail with reference to the flowchart of FIG. Since most of the usual samples have a cubic crystal structure, the crystal orientation is described here using the Miller index (hkl). Further, here, a case will be described in which the directions of the two rotation axes (X axis, Y axis) of the commonly used biaxial sample tilting device and the direction of the electron beam are at right angles in the initial state.

First, a single crystal or polycrystal sample is inserted into an electron microscope, and the sample is moved to the field of view of the crystal to be observed. The initial crystal orientation of the observed crystal in the non-tilted state is (h ₀ k ₀ l ₀ ). This orientation (h ₀ k ₀ l ₀ ) is an unknown orientation that has not yet been indexed.

The sample is tilted to a reference crystal orientation (h ₁ k ₁ l ₁ ) which has good symmetry so that the index of the crystal orientation can be determined by observing the diffraction pattern. The rotation angles x ₁ and y ₁ due to the rotation around the X axis and the Y axis at that time are read from the angle scale attached to the rotation mechanism. Further, reference crystal orientations (h ₂ k ₂ l ₂ ), (h ₃
The sample is tilted to k ₃ l ₃ ) and the X axis and Y at each time are tilted.
Read the rotation angles x ₂ , y ₂ and x ₃ , y ₃ about the axis. These three operations satisfy the following relationship.

[0011]

[Equation 1]

Therefore, the known orientation (h ₁ k
₁ l ₁ ), (h ₂ k ₂ l ₂ ), (h ₃ k ₃ l ₃ ) and the measured rotation angles x ₁ , y ₁ , x ₂ , y ₂ , x ₃ , y ₃ are given by equation (1), By substituting the equations (2) and (3), the unknown azimuth (h ₀ k ₀ l ₀ ) can be obtained.

Next, a method for tilting the sample to the target crystal orientation (h ₄ k ₄ l ₄ ) will be described. The rotation angles x ₄ and y ₄ of the biaxial rotation mechanism for rotating in that direction are obtained. The rotation angles x ₄ and y ₄ satisfy the following formula.

[0014]

[Equation 2]

Therefore, (4), (5) and (6)
Substituting the target crystallographic orientation (h ₄ k ₄ l ₄ ) into the equation, x
₄ and y ₄ can be obtained. It is easy to perform the above series of calculations by a computer.

Next, the computer issues a command to the drive power source so that the two motors are driven by the components of the rotation angles x ₄ and y ₄ of the thus calculated two-axis motor. Thereby,
Electric power is supplied from the power supply to the electric motor, and the electric motor is rotated so that the sample has a target crystal orientation with respect to the electron beam. Under this direction, the image of the transmission electron microscope and the diffraction pattern are observed.
When subsequently observing the sample in another crystal orientation, the tilt is repeated in the same procedure.

The rotation angle component of the sample tilt up to the target azimuth can be obtained by using equations (1) to (6), but the present invention is not limited to this, and equation (1) to (6) is used. ) And mathematically equivalent formulas, for example, formulas consisting of different combinations of them, and the rotation angle component can be obtained even if the relative geometric arrangement of the rotation axis and the direction of the electron beam is different. Is.

[0018]

EXAMPLES Examples of the sample tilting operation method of the present invention will be described. A polycrystal of molybdenum having a cubic crystal structure was mounted on a sample holder for a transmission electron microscope having a sample rotation mechanism composed of two rotation axes perpendicular to the direction of the electron beam. The sample is not tilted with the sample still inserted. After inserting the sample holder into the electron microscope, the observation position of the sample was moved to the observation position of the electron beam.

First, the observation mode was changed to a diffraction pattern and the initial orientation was observed. X ₁ = 1 with two rotating mechanisms from that direction
When rotated by 9.1 ° and y ₁ = 0 °, a two-fold symmetrical (011) diffraction pattern was obtained. Then x ₂ = 10.9
When tilted by °, y ₂ = -35.3 °, a four-fold symmetric (001) diffraction pattern is obtained, and x ₃ = 1
When tilted by 0.9 ° and y ₃ = 19.5 °, a three-fold symmetrical (111) diffraction pattern was obtained. When these reference orientations and rotation angles were substituted into the equations (1) to (3) to determine the initial crystal orientation at the time of inserting the sample, (123) was the initial orientation.

Next, the procedure for inclining to the target azimuth (112) will be described. By substituting the target azimuth and the reference azimuth and the previously obtained rotation angle into the expressions (4) to (6), the rotation angle up to the target azimuth can be calculated x ₄ = 10.
9 ° and y ₄ = 0 ° are obtained. When the motor of the biaxial sample tilting device was rotated by this rotation angle component, the sample orientation became the target crystal orientation (112), and the target orientation was obtained.

[0021]

According to the sample tilt control method of the present invention,
The desired sample tilting can be performed in a short time, and the sample tilting operation can be easily performed in a series of operations of the transmission electron microscope.
Therefore, the operability when observing the diffraction pattern of the sample with the transmission electron microscope and observing the image under the condition is further improved.

Therefore, when the transmission image is observed while examining the diffraction conditions in detail, the operation time of the transmission electron microscope is less than half that in the case of operating with the conventional apparatus, and the transmission electron microscope can be operated efficiently. Along with that, the maintenance cost, which is indispensable for the operation of the transmission electron microscope, is reduced, and the economic effect is great.

[Brief description of drawings]

FIG. 1 shows a flow chart of a sample tilt operating method of the present invention.

Claims (1)

[Claims] 1. A method for inclining a sample for a transmission electron microscope by a biaxial sample rotating mechanism, wherein an azimuth relationship between an initial azimuth and a reference azimuth of a crystalline sample is determined by rotating respective motors of the biaxial sample rotating mechanism. Then, the rotation component of the biaxial sample rotation mechanism for tilting the sample to the target crystal orientation is calculated from the relationship between the initial orientation, the reference orientation and the target orientation by a computer, and only the rotation component is A method for tilting a sample in a transmission electron microscope, wherein the sample is tilted by simultaneously driving a sample rotating mechanism of a shaft.