JPS58115383A - Reflected electron detector - Google Patents

Abstract

PURPOSE:To simplify structure and handling and to obtain an excellent sample structure image free of shadow by fitting a discoid electron-beam detecting element which has a hole in the center to the upper part of a sample holder. CONSTITUTION:The reflected electron detecting element 4 is fitted to the top surface of an insulating material 2 by an electron absorber such as carbon. In the center of the element 4, the opening 41 is made to irradiate a sample 3 with an electron beam from above. A reflected electron 8 from the sample 3 is detected directly by the element 4 and a reflected electron 9 strikes the reverse surface of an objective lens 12 through the opening 41 to radiate a secondary electron 11, which is caused to strike the detecting element 4. A secondary electron 10 from the sample 3 is acquired by the element 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a backscattered electron detector used in an electron beam microanalyzer or the like.

Conventionally, when using an electron beam microanalyzer etc. to detect reflected electrons from a sample irradiated with an electron beam and obtain information on the atomic number dependence of the sample surface, an electron beam detector was attached to the bottom surface of the objective lens. method was used. When using this method, it is necessary to prepare a mechanism on the bottom surface of the objective lens for attaching a detector for detecting backscattered electrons. Since it is necessary to attach the detector to the objective lens on the bottom surface, the structure is complicated and expensive, and it is troublesome to attach and detach the detector. The present invention aims to solve the above-mentioned problems of the conventional example in detecting reflected electrons from a sample.

The present invention provides a backscattered electron detector having a structure in which a disk-shaped electron beam detection element with a hole in the center is attached to the upper part of a sample holder. The present invention will be explained below with reference to Examples.

FIG. 1 shows an embodiment of the invention. 1 is a sample holder, 2
3 is an insulating material provided above the sample holder, and 3 is a sample. Reference numeral 4 denotes a backscattered electron detection element, which is made of an electron absorber such as carbon, and is attached to the upper surface of the insulating material 2. 5 is a shield wire of a signal line led out from the backscattered electron detection element 4 and connected to an amplifier circuit. An opening 41 is provided in the center of the backscattered electron detection element 4, so that the sample can be irradiated with the electron beam 7 from above. 12 is an objective lens. 8 and 9d are examples of reflected electrons emitted from the sample, and 8 is incident on the detection element 4 and directly detected. Since electrons 9 pass through the aperture 41 of the detection element 4, they cannot be directly detected, but they collide with the lower surface of the objective lens 12 and emit secondary electrons 11 from the lower surface of the objective lens 12, which enter the detection element 4. This will provide a backscattered electron detection current. 10 is 2 emitted from sample 3
The second electron is also captured by the backscattered electron detection element 4.

The backscattered electron detection element 4 is basically in the shape of a disk with a hole, but as shown in FIG. The angle is enlarged and even reflected electrons emitted from the sample surface at a low angle can be captured, improving detection sensitivity.

On the upper side, the backscattered electron detection element is made of a conductor such as carbon that emits low secondary electrons and does not have any amplification effect. By using a semiconductor detector as the detection element, the backscattered electron detection element itself can have an amplification effect.

Since the backscattered electron detector of the present invention has the above-described configuration and the backscattered electron detection element is a part of the sample holder, there is no need to provide a mechanism for attaching the backscattered electron detection element to the objective lens, etc. Therefore, it is structurally simple, low cost, and easy to handle. Since the trench has a uniform structure all around the sample center, it is possible to obtain an extremely good sample structure image with no shadows.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of an apparatus according to one embodiment of the present invention, and FIG. 2 is a longitudinal sectional side view of a main part of an apparatus according to another embodiment of the invention. 1... Sample holder, 2... Insulating material, 3... Sample,
4... Backscattered electron detection element, 12... Objective lens. Agent Patent Attorney Kosuke Agata

Claims (1)

[Claims] A backscattered electron detector is a backscattered electron detector in which a disk-shaped electron detection element with an opening in the center directly above the sample and an electron detection surface on the bottom is electrically insulated and mounted on the top of the sample holder.