JPS5830698B2 - electron spectrometer - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in electron spectroscopy devices.

In general, in Auger electron spectrometers and the like, the internal structure of a sample is frequently analyzed by irradiating the sample with accelerated ions to repel atoms on the surface of the sample and etching them.

The atoms repelled by this etching adhere to the entrance slit of the energy analyzer and the inner wall of the electrostatic electrode that constitutes the analyzer.

If the sample to be analyzed at this time is a conductive material, problems such as leakage will not occur, but if the sample is an insulating material, the following problems will occur.

That is, the insulator attached to the inside of the energy analyzer is irradiated with secondary ions from the sample during etching, resulting in charge-up.

This charge-up disturbs the electric field of the energy analyzer or changes the electric field intensity, causing a decrease in spectral intensity and/or a shift in energy position.

In order to prevent such inconveniences, an apparatus has been proposed in which a negative bias voltage of approximately several tens of volts is applied to the sample to prevent secondary ions from entering the energy analyzer from the sample.

However, in such an apparatus, Auger electrons generated from the sample by electron beam irradiation are accelerated by a negative bias voltage applied to the sample, so the energy position of the spectrum is shifted by the potential, making it difficult to identify elements. The disadvantage is that it causes trouble.

The present invention aims to solve such inconveniences, and will be explained in detail below with reference to the drawings.

The attached drawings are schematic diagrams showing an embodiment of the present invention, and 1
is an electron gun.

The electron beam 2 generated by the electron gun is narrowly focused by a focusing lens 3 and irradiated onto a sample 4.

Auger electrons e generated from the sample by the electron beam irradiation are introduced into a cylindrical energy analyzer 6 consisting of an outer cylinder 5a and an inner cylinder 5b arranged coaxially, and a sweep power supply 7 connects the outer cylinder and the inner cylinder. The electric field formed between the cylinders deflects and focuses the beam according to its energy and is detected by the detector 8.

Therefore, the spectrum of Auger electrons can be obtained by varying the voltage of the power source 7 and sweeping the potential difference between the outer cylinder 5a and the inner cylinder 5b.

Reference numeral 9 denotes an ion generation source placed to face the sample 4, and by accelerating ions (1) generated from the ion generation source and irradiating the sample 4 with the accelerated ions, the surface of the sample can be etched.

Reference numeral 10 denotes a variable pie-sumi source for applying a negative bias voltage of, for example, several +V to the sample 4 in order to prevent secondary ions reflected on the sample 4 from entering the energy analyzer 6.

Now, the energy value of the Auger electron to be measured is Ei, and the outer fm5a of the energy analyzer 6 and the inner cylinder 5 at that time are
When the potential difference between b and b is 1, the following relationship holds between the two.

Ei2 AV・・・・・・・・・・・・・・・・・・
(1) In S, A is a constant determined by the shape of the energy analyzer used.

Therefore, when a negative bias voltage of v2 is applied to the sample 4 by the bias power supply 10, the Auger electrons e having energy of Ei are transferred to the energy analyzer 6 due to this negative bias voltage. becomes an electron, and the actual measured value is V2eV
Just shift.

Therefore, when applying a bias voltage to the sample 4 and at the same time applying a bias voltage ■3 to the energy analyzer 6 from the variable bias power supply 11, E i +V2=A (V
1+V3)−”·(2) holds true.

Therefore, if the bias voltage v3 applied to the energy analyzer at this time is set as ■3 knee ■2, the relationship between the energy value Ei unique to the Auger electron spectrum and the sweep potential of the energy analyzer always satisfies equation (1), and the energy The value never shifts.

As a result, elements can be identified more accurately than conventional devices.

The bias power supplies 10 and 11 may be interlocked as shown by the dotted line in the figure.

Furthermore, when negative secondary ions are generated from a sample, it is no longer the case that a positive bias voltage is applied to the sample and the energy analyzer.

[Brief explanation of the drawing]

The accompanying drawings are schematic diagrams showing an embodiment of the present invention. In the figure, 1 is an electron gun, 2 is an electron beam, 3 is a focusing lens,
4 is a sample, 6 is a cylindrical energy analyzer consisting of an outer tube 5a and an inner tube 5b, γ is a power source, 8 is a detector, 9 is an ion source, and 10 and 11 are bias power sources.

Claims (1)

[Claims] 1. A means for irradiating a sample with radiation to generate electrons having a specific energy from the sample, an energy analysis means for energy analysis of the electrons generated by the means, and irradiating the sample with ions. An electron spectroscopy apparatus comprising means for applying a bias voltage to the sample and to the electron beam incidence section of the energy analysis means, and also applying a bias voltage to the energy analyzer.