JPS645746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus capable of high-resolution energy analysis over a wide energy range.

For example, in a transmission electron microscope, an apparatus is in practical use in which an electron beam transmitted through a sample is guided to an energy analyzer to obtain a spectrum of energy loss due to the sample. An example of this device is shown in FIG. In the figure, 1 is a sample, and the sample is irradiated with an electron beam 2 emitted from an electron gun (not shown) and focused by a focusing lens. The sample 1 is thin and easy for electrons to pass through, and the electrons that have passed through the sample and suffered energy loss are imaged by a wire-connection lens system 3 such as an objective lens. The electrons after the image formation are introduced into an energy analyzer 4,
The energy is analyzed and focused onto the slit 5 of the detector. The electron beam passing through the slit is detected by a detector 6, and its output is supplied to a display device or recorder 8 via an amplifier 7. Excitation coil 9 of the energy analyzer
An energy sweep signal is supplied from a power supply 10 to the detector, and electrons of different energies are made to enter the detector one after another. A part of the output from the power source is also sent to the display device 8, on which an energy spectrum based on the signal from the detector is obtained.

In such an apparatus, electrons that pass through the sample and undergo little energy loss are imaged by the imaging lens system at position a (solid line) in the figure, whereas electrons with energy loss are imaged at position b (dotted line), for example. ). The electron beam with these points as the incident point is split into spectra by the analyzer 4, and at the same time
Images are formed on a′ and b′. As can be seen from the figure, a' is focused exactly on the slit 5, but b' is focused much further forward, so the magnetic field strength is changed by the sweep signal from the power supply 10, and the dotted line indicates Even if the shown electrons pass through the slit 5, the electron beam has already begun to be dispersed, so that part of it is blocked by the slit, and at the same time, electrons of different energies begin to be incident. Therefore, the resolution of energy analysis is extremely low. Moreover, the resolution differs depending on the energy, making analysis difficult.

The present invention aims to eliminate the drawbacks of the above-mentioned conventional apparatus, and consists of a means for irradiating a sample with a focused charged particle beam, a means for irradiating a sample with a focused charged particle beam, and a means for irradiating a sample with a focused charged particle beam; A lens system for imaging a particle beam, an analyzer for energy analysis of the charged particle beam from the lens system, a detector for detecting the charged particle beam separated by the analyzer, means for sweeping the analyzer, and an output of the detector. In an apparatus comprising a display or recording device synchronized with said sweep into which a signal is introduced, the excitation intensity of said imaging lens system is adjusted in response to said sweep of said analyzer such that charged particles of a selected energy are always present on said detector. It is characterized by a charged particle beam energy analyzer that is controlled to be focused onto a slit.

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 2 shows one embodiment of the present invention.
The same reference numerals as in the figures indicate the same components. 1
Reference numeral 1 denotes a circuit that controls the direct current from the power source 12 of the imaging lens system, and is controlled by a signal from the amplifier 13. The output of the sweep power supply of the energy analyzer is fed to the amplifier, so that the lens current is varied in proportion to the sweep of the analyzer. That is, when there is no or little energy loss of the electron beam, if the energy loss increases, the excitation intensity of the imaging lens system is weakened to lower the imaging point b, as shown in Figure 3. The electrons, which have been focused in front of the slit 5, now focus exactly on the slit, and are no longer incident on the slit during the dispersion process as in the prior art.

As described above, in the present invention, no matter how the energy analyzer is swept, the excitation intensity of the imaging lens system is varied accordingly, and the electrons with the selected energy are always focused on the slit 5, thereby reducing energy loss. The drawback of conventional devices in which the resolution gradually decreases as the size increases is completely eliminated.

It should be noted that the above is an example of the present invention, and it goes without saying that various modifications are possible. For example, although the case of an electron beam applied to a transmission electron microscope has been described above, the charged particle beam may also be an ion beam. Further, the energy analyzer is not limited to the shape shown in the drawings.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional device.
FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a diagram for explaining the operation of FIG. 1: Sample, 2: Irradiation electron beam, 3: Imaging lens system, 4: Energy analyzer, 5: Detector slit, 6: Detector, 7: Amplifier, 8: Display or recording device, 9: Excitation coil, 10 :Sweep power supply, 1
1: Control circuit, 12: Lens power supply, 13: Amplifier.

Claims (1)

[Claims] 1. A means for irradiating a sample with a focused charged particle beam, a lens system that forms an image of the charged particle beam that has undergone energy loss due to the sample, an analyzer that analyzes the energy of the charged particle beam from the lens system, and separation by the analyzer. A device comprising a detector for detecting a charged particle beam, a means for sweeping the analyzer, and a display or recording device synchronized with the sweep into which an output signal of the detector is introduced,
Charged particle beam energy analysis characterized in that the excitation intensity of the imaging lens system is controlled in response to the sweep of the analyzer so that charged particles of a selected energy are always focused onto the slit of the detector. Device.