JPH02168548A - Charged particle beam irradiation type X-ray analyzer - Google Patents

Abstract

PURPOSE:To make measurement with good S/N ratio by arranging the X-ray incident surface of a sensing element, wherein a through hole is provided in the center of the X-ray incident surface, so as to face the specimen surface, and permitting a charged particle beam to penetrate this through hole. CONSTITUTION:A charged particle beam BB penetrates a through hole (h) provided in the center of a disc-shaped semiconductor X-ray sensing element D. X-ray emitted from a specimen S is irradiated onto the sensing element D, which generates panel current with an intensity proportional to the energy for the incident X-ray light quantum. The pulse current signal is amplified by a preamplifier PA and a proportional amplifier LA, and the pulse signals in a wave height range corresponding to the energy of characteristic X-ray to be measured are taken out and counted by a counter C. This constitution enables approach of the X-ray sensing surface to the specimen surface, allows easy enlargement of the stereophonic angle formed by the specimen surface with respect to the beam irradiation point O, accomplishes good X-ray incident efficiency, and enchances the analytical sensitivity and the accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to the application of charged particles (
The X! l! This invention relates to i1 spectral detection means.

(Prior art) In the above-mentioned analysis device, X-ray spectroscopy uses a wavelength dispersion method using a spectroscopic crystal, or a proportional counter or semiconductor detector that outputs a pulse with a wave height proportional to the photon energy of incident X-rays. An energy dispersive method is used, but conventionally, with either method, the X-ray spectroscopic detection means was installed so that it looked at the beam irradiation point on the sample from a direction different from the sample irradiation beam. .

Such conventional X-ray spectroscopy detection means are located far from the beam irradiation point on the sample, and the solid angle with respect to the sample beam irradiation point is small, resulting in low X-ray incidence efficiency, and the radiation from the sample is small. When measuring characteristic X-rays, the ratio of the intensity of the characteristic X-rays to the continuous X-ray intensity due to the bremsstrahlung radiation of sample irradiation particles, which serves as the background, is maximum in the direction opposite to the irradiation direction of the irradiation beam, and increases as the distance from the vertical direction increases. However, in the conventional method, X-rays are detected in a direction far away from this irradiation beam, resulting in a low measurement S/N ratio.

(Problems to be Solved by the Invention) The present invention improves the incidence efficiency of X-rays and improves the S/N ratio in a device that irradiates a sample surface with a charged particle beam and spectrally detects the X-rays emitted from the sample. The present invention aims to provide a standardized X-ray spectroscopic detection device.

(Means for Solving the Problem) An X-ray detection element having a through hole in the center of the X-ray entrance surface is arranged so that the charged particle beam that irradiates the sample passes through the hole, and the X-ray entrance surface is made to face the sample surface. It was placed towards.

(Function) According to the present invention, the X-ray detection element is arranged surrounding the charged particle beam that irradiates the sample, and the X-ray incident surface is directed toward the sample, so the X-ray extraction angle from the sample surface is 90°. Therefore, characteristic X-rays can be detected with a good S/N ratio, and there are fewer structural restrictions on the arrangement of the The solid angle formed with respect to the beam irradiation point of the sample on the surface can be made larger than before, and the X-ray incidence efficiency can be increased.

(Embodiment) The figure shows an apparatus according to an embodiment of the present invention. In the figure, B is the charged particle beam that irradiates the sample, L is the objective lens, and S is the sample. D is an X-ray detection element according to the present invention, which is a semiconductor X-ray detection element formed in a disk shape, and has a hole in the center so that the charged particle beam B can pass through. X-rays emitted from the sample enter the X-ray detection element as shown by arrows X in the figure. In response to incident X-ray photons, a semiconductor X-ray detection element generates a pulse current whose strength is proportional to the energy of the incident X-ray photons. This pulse current signal is the preamplifier P
After being amplified by the A proportional amplifier LA, the pulse height analyzer PICA
A pulse signal having a wave height range corresponding to the energy of the X-ray to be measured is extracted and counted by a counter C.

(Effects of the Invention) Conventional devices of this type emit X-rays in the direction shown by the chain line in the figure, but in the present invention, as is clear from the figure, the X-rays are emitted in the opposite direction to the incident direction of the sample irradiation beam. Since X-rays are detected, the ratio of the characteristic X-ray intensity of the sample to the background is higher than that of the conventional example, and S/
Good N-ratio measurements can be made, and since the xvA detection element is placed surrounding the sample irradiation beam and close to it,
There are few structural restrictions on the arrangement of the radiation detection element, and it is possible to bring the X-ray detection surface closer to the sample surface and easily increase the solid angle with respect to the beam irradiation point O on the sample surface. Because of this, the X-ray incidence efficiency is good, the analytical sensitivity is 9.2 times higher than that of the conventional analyzer, and the structure is simpler.

[Brief explanation of the drawing]

The drawing is a side view of an apparatus according to an embodiment of the present invention. B...Charged particle beam, L...Objective lens, S...
・Sample, D...X-ray detector, h...Through hole, PHA・
... Wave height analyzer, C... Counter. Agent Patent Attorney Kosuke Agata

Claims (1)

[Claims] An X-ray detection element with a through hole in the center of the X-ray incident surface is
A charged particle beam irradiation type X-ray analyzer characterized in that the ray incidence surface is directed toward the sample and the charged particle beam irradiating the sample surface is arranged so as to pass through the through hole.