JPH0114666B2 - - Google Patents

Description

Detailed Description of the Invention In photoelectron spectroscopy and other various electron spectroscopy analyses, the angular dependence of the kinetic energy of electrons or ions emitted from a sample with respect to the sample surface is investigated to determine adsorption or crystal orientation on the sample surface. There is a way to find out. The present invention relates to an apparatus suitable for this type of charged particle energy analysis.

Conventionally, in order to investigate the angular dependence of charged particles emitted from a sample irradiated with various excitation lines, it is necessary to change the tilt of the sample with respect to the direction of incidence of the charged particles into the energy analyzer, or conversely, to fix the sample. A method was used in which the energy analyzer was rotated. In such conventional examples, when the tilt of the sample is changed, the excitation ray irradiation area of the sample changes and the apparent number of emitted charged particles changes, and when the energy analyzer is rotated, the apparatus becomes larger and more complex. In addition, both methods have the disadvantage that measurement takes time because the slope must be changed over time.

In view of the above-mentioned current situation, it is an object of the present invention to provide a charged particle energy analyzer that can simultaneously detect charged particles emitted at each angle without moving either the sample or the energy analyzer. It was done for a purpose. The present invention provides a charged particle energy analyzer that takes advantage of the fact that the low-pass filter acts as a reflecting mirror for charged particle beams. A charged particle energy analyzer is provided in which charged particles emitted within a three-dimensional angle range are reflected in parallel or substantially parallel and incident on a detection surface. The present invention will be explained below with reference to Examples.

FIG. 1 shows an embodiment of the invention. 1 is a rotating rod surface made of a conductor, 2 is a grid stretched parallel to the front surface, and the rotating rod surface 1 is connected to the grid 2.
is biased to the same polarity as the charged particles to be analyzed, and 1 and 2 form a low-pass filter. A sample S is placed at the focal point of the rotating rod surface 1. An excitation line entrance hole 3 is provided in the center of the rotating rod surface 1, and X
An excitation ray such as a beam, an ion beam, an electron beam, or an ultraviolet ray is made incident on the sample S. The sample S is held at ground potential and electrostatically shielded from the surrounding space by a spherical grid 4 and a shielding box 5 with the sample S at the center. 6, 7, 8 are plane grids, and the parapet surface 1
It is perpendicular to the device optical axis connecting the center of the sample S and
Grids 6 and 7 constitute a high pass filter. In the high pass filter, grid 7 is biased with respect to grid 6 to have the same polarity as the charged particles to be analyzed. grid 2, 4,
6 and the lens barrel 9 are at the same potential. grid 8
is biased to accelerate charged particles passing through grid 7. 10 is a charged particle detector that uses, for example, a fluorescent screen. After the fluorescent screen 10, a two-dimensional detector such as a photographic plate or channel plate, an image intensifier, etc. are arranged to record or visualize a fluorescent image.

In the low-pass filter, an electric field is formed between the grid 2 and the parapet surface 1 that decelerates the charged particles to be analyzed, so that charged particles whose velocity is lower than a certain level, that is, whose energy is low, are reflected in the electric field. When the low-pass filter is in the form of a parapet surface, the sample S, which is the source of the charged particles, is at its focal point, so the reflected low-energy particles form a parallel beam bundle.
This bundle of parallel lines enters the high-pass filter constituted by grids 6 and 7 perpendicularly. Even in a high-pass filter, an electric field is formed in the direction that decelerates the charged particles to be analyzed.
Among the incident charged particles, those with energy lower than a certain level cannot pass through the high-pass filter and are reflected. In this way, only charged particles in a certain narrow energy range pass through the high-pass filter. Since the particles passing through the high pass filter have very low velocities, they are accelerated by the grid 8 and incident on the fluorescent screen 10.

Charged particles emitted from the sample S in a direction at an angle θ with respect to the normal to the sample surface are reflected by a low-pass filter, become parallel, and travel along a cylinder with a radius r. Light is emitted along the cylinder. Therefore, when the density of charged particles of a certain energy emitted from the sample S is a function of the angle θ, a pattern with a concentric concentration distribution is generated on the fluorescent screen 10 as shown in FIG. A function of the angle θ is determined from the pattern.

The charged particle energy analyzer of the present invention has the above-described configuration and can simultaneously detect the angular distribution of charged particles of arbitrary energy emitted from the sample as a concentric concentration distribution, so it takes a shorter time than when performing angular scanning. The analysis can be performed with a good S/N ratio, the excitation area does not change because the sample is not tilted, the device is small and simple because there are no moving parts, and the angular distribution of particles is detected as a concentric concentration distribution. Therefore, it is possible to obtain information regarding crystals on the sample surface, non-uniformity of orientation, etc. from the disorder of the shape of the concentric pattern.

In the above embodiment, the low-pass filter is placed on a spherical surface and the sample is placed at its focal point, but if measurement over a very wide range is not required, the low-pass filter may be placed on a spherical surface at a position that bisects the sample and its radius of curvature. It is possible to approximate the configuration of the above embodiment.

Furthermore, in any case, the sample does not necessarily need to be placed at the focal position, but may be slightly shifted from that position, thereby making it possible to obtain an enlarged or reduced pattern.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view of a pattern obtained by the above-mentioned apparatus. 1... Parameter surface, 2... Grid, 3... Excitation line entrance hole, S... Sample, 6, 7, 8... Plane grid, 10
…Detector.

Claims (1)

[Claims] 1 Consists of a low-pass filter that reflects charged particles with energy lower than a certain value and a high-pass filter that transmits charged particles with energy higher than a certain value. A charged particle energy analyzer characterized in that it is adapted to be installed.