JPS63205551A - Auger electron spectroscopic device - Google Patents

Abstract

PURPOSE:To obtain a current Auger electron image by constituting a titled device in such a manner that an Auger electron detection signal is standardized by the signal detected by a reflected electron detector and said signal is introduced to a display device to observe the Auger electron image of a sample. CONSTITUTION:A scanning signal generator 9 supplies two-dimensional scanning signals to deflectors 8x, 8y and supplies the synchronized signals to deflectors 11x, 11y of a display device 10 as well. The reflected electron detector 12 is disposed between an incident slit 5a of a cylindrical mirror analyzer 3a and the sample 2. The detection signal of the detector 12 is supplied as a signal Sb via an amplifier 13 to a divider 14. On the other hand, the signal Sb of an Auger electron detector 6 is supplied to a divider 14 as well by which a signal ratio Sa/Sb is determined. The signals determined in such a manner are supplied as signals for modulating luminance of a device 10. The signal which is canceled in a surface shape effect is obtd. when the signal Sa is divided by Sb. The signal standardized by the signal of the reflected electrons is introduced as a luminance signal to the device 10, by which the correct Auger electron image is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is for improving Auger electron spectrometers, particularly for obtaining sample images using Auger electrons having a specific energy, and for obtaining line spectra using Auger electrons having a specific energy. This invention relates to an Auger electron spectrometer that eliminates the effects of unevenness on the surface of a sample.

[Prior art] Auger electron spectroscopy uses an energy analyzer to analyze the energy of electrons backscattered from a sample when the sample is irradiated with a focused electron beam, thereby performing qualitative and quantitative analysis of the sample. However, since Auger electrons have low energy and are only generated from the extreme surface layer of a sample, Auger electron spectroscopy has recently been in the spotlight as a technique for analyzing the surface of samples, and is rapidly becoming popular.

Figure 3 is a schematic diagram showing the main parts of a conventional general Auger electron spectrometer. 1 is a focusing lens, which narrowly focuses the electron beam from an electron gun (not shown) and irradiates it onto the sample 2. do. 3 is a cylindrical mirror analyzer configured by coaxially arranging cylinders (or semi-cylinders) 3a and 3b, the inner cylinder 3a is at ground potential, and the outer cylinder 3b is a variable DC? ! m4
A negative voltage -Vo is applied from. The inner cylinder 3a has an annular slit 5a for the incidence of Auger electrons and an annular slit 5b for output, and the Auger electrons generated from the sample 2 enter between the inner cylinder 3a and the outer cylinder 3b through 5a and are formed therein. The energy of the electrons is analyzed by the analysis electric field, and electrons having a specific energy are extracted from the emission slit 5b and enter the detector 6. The output signal of this detector is amplified by an amplifier 7, subjected to appropriate signal processing, and then introduced to a display device such as a cathode ray tube or a recording device. 8x, 8V
is an electron beam deflector, and is used to scan or move the electron beam on the sample as desired.

A display device such as the cathode ray tube is synchronized with this electron beam deflector, and when a detection signal is introduced into the cathode ray tube as a luminance signal, an Auger electron image of the sample is formed on the cathode ray tube. Furthermore, since the energy of Auger electrons emitted from the emission slit 5b changes when the voltage Vo applied to the outer tube 3b is changed, a line spectrum of Auger electrons can be obtained by sweeping the voltage over a certain range.

[Problems to be Solved by the Invention] However, when the surface of the sample 2 is uneven as shown in FIG. As shown in FIG. 5, the spectral intensity becomes strong, and conversely, the spectral intensity becomes small on the surface (2) inclined toward the side opposite to the analyzer. In FIG. 5, the vertical axis represents the detected intensity, and the horizontal axis represents the energy of Auger electrons. Therefore, even if an attempt was made to obtain an Auger electron image (element distribution image) using a conventional apparatus, a correct compositional image could not be obtained with a sample having an uneven surface due to the influence of the surface shape.

In view of the above-mentioned points, an object of the present invention is to provide an Auger electron spectrometer capable of obtaining an accurate compositional image regardless of the surface condition of a sample.

[Means for Solving the Problem] The present invention provides a means for irradiating a sample with a focused electron beam, a deflection system for arbitrarily scanning and moving the electron beam on the sample, and a means for irradiating a focused electron beam onto a sample. An apparatus comprising an energy analyzer for dispersing the energy of Auger electrons, a detector for detecting the Auger electrons separated by the energy analyzer, and a display device or a recording device into which the detection signal is introduced. A backscattered electron detector is placed in front, and the ratio S a of the Auger electron signal Sa, which is spectrally spectrally analyzed by the energy analyzer and detected by the detector, and the detection signal Sb of the backscattered electrons.
The Auger electron spectroscopy apparatus is characterized in that it is equipped with a means for determining Sa/Sb and introduces the signal Sa/Sb into the display device or recording device.

[Function] In the present invention, in addition to the Auger electron detector, a backscattered electron detector is placed in front of the energy analyzer, and the Auger electron detection signal and the anti-IJ4i! ! The ratio of the analogous detection signals is calculated, and the analogous signal is introduced into the display device to eliminate the influence of the sample surface on Auger electrons incident on the energy analyzer.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention.
The same reference numerals as in FIG. 3 indicate similar components. In the figure, 9 is a scanning signal generator that supplies two-dimensional scanning signals to the electron beam deflectors Qx and ay, and
A synchronized signal is also supplied to the deflectors 11X and 11V of the display device 10. Between the entrance slit 5a of the inner cylinder 3a of the cylindrical mirror analyzer and the sample 2 (in front of the energy analyzer), there is a detector 12 that detects electrons reflected from the sample surface when the sample 2 is irradiated with an electron beam. It is located. As this detector, for example, a semiconductor detector (P-N junction detector) that can be formed into a small size is used.
The detection signal is supplied to a divider 14 via an amplifier 13 as a signal sb. Signal S of the Auger electron detector
a is also supplied to the divider 14, and the reflected electron detection signal S
The ratio Sa/Sb with b is determined. The signal obtained in this manner is supplied as a brightness modulation signal to the display device 10. An image of a specific energy (specific element) is formed on a display device.

In such a device, the anti-t detected by the detector 12
Since the JJ electron signal sb is placed in the Auger electron detection direction (in front of the energy analyzer), the JJ electron signal sb is subject to the same sample surface shape effect as the Auger electron detection signal Sa. Dividing the signal Sa by the signal sb of the reflected electrons results in a signal in which the surface shape effect is canceled. By introducing a signal normalized by the reflected electron signal into a display device as a luminance signal, an Auger electron image almost unaffected by the surface shape can be obtained.

FIG. 2 shows the main part of another embodiment of the present invention, in which logarithmic amplifiers are used as the amplifier 7 of the Auger electron detector and the backscattered electron detector 13, respectively.

The signals Sa, log, and 9b are obtained, and the subtraction circuit 15 performs subtraction (I oa, Sa-l, oQ, Sb), and the result is converted into an antilog by the antilog amplifier 16, and Sa/S
This is configured to obtain the signal b, and the result is exactly the same as that of the divider shown in FIG.

[Effect 1 As explained above, in the present invention, a backscattered electron detector is installed at the entrance of the Auger electron energy analyzer, the Auger electron detection signal is normalized by the signal detected by this detector, and the signal is displayed on the display device. Since the structure is such that the Auger electron beam of the sample is observed by introducing the sample into can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention. 2 is a block diagram of the main parts showing another embodiment of the present invention, FIG. 3 is a diagram showing the main parts of a conventional Auger electron spectrometer, and FIGS. FIG. 1: Focusing lens 2: Sample 3 Nijilintrical mirror analyzer 3a: Inner cylinder
3b: Outer cylinder 4: DC electric It! 5a: entrance slit 5b
= Output slit 6: Auger electron detector 7: Amplifier Bx, sy: Deflector 9: Scanning signal generator 10: Display device 11X, 11V: Display device deflector 12: Backscattered electron detector 13: Amplifier 14: Division Device 15: Subtractor 16 Two-log amplifier

Claims (1)

[Claims] means for irradiating a sample with a focused electron beam; a deflection system for arbitrarily scanning and moving the electron beam on the sample; an energy analyzer for dispersing the energy of Auger electrons generated from the sample by irradiation with the electron beam; In this device, which has a detector for detecting Auger electrons spectrally spectrolated by the energy analyzer, and a display device or a recording device into which the detection signal is introduced, a backscattered electron detector is disposed in front of the energy analyzer, and Auger electron signal Sa spectrally analyzed by the analyzer and detected by the detector
and the detection signal Sb of the reflected electrons, the Auger electron spectrometer comprising means for determining the ratio Sa/Sb of the reflected electrons and the reflected electron detection signal Sb, and is configured to introduce the signal Sa/Sb into the display device or the recording device.