JPH0413674B2 - - Google Patents

Description

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

When detecting reflected electrons from a sample irradiated with an electron beam using a conventional electron beam microanalyzer or the like to obtain information on the atomic number dependence of the sample surface,
A method was used in which an electron beam detector was attached to the bottom surface of the objective lens. When using this method, it is necessary to prepare a mechanism on the bottom surface of the objective lens to attach a detector for detecting backscattered electrons.
In preparation for detecting backscattered electrons in all directions, it is necessary to be able to attach multiple detectors to the bottom surface of the objective lens, which results in a complex and expensive structure, and it is troublesome to attach and detach the detectors. Ta. The present invention aims to solve the above-mentioned problems of the conventional method 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 is an insulating material provided on the upper edge of the sample holder, and 3 is a sample. 4 is a backscattered electron detection element, which is an electron absorber such as carbon, and the above-mentioned insulating material 2
It is designed to be installed on the top surface of the 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,
9 is an example of reflected electrons emitted from the sample, and 8
enters the detection element 4 and is directly detected. Since electrons 9 pass through the aperture 41 of the detection element 4, they are not 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 reflected electron detection current. Reference numeral 10 indicates secondary electrons emitted from the sample 3, which are 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.

In the above example, the backscattered electron detection element is made of a conductor such as carbon that emits low secondary electrons and does not have an amplification effect itself. 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. Furthermore, since the structure is uniform all around the sample center, it is possible to obtain an extremely good sample structure image without shadows.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of an apparatus according to an embodiment of the present invention;
FIG. 2 is a longitudinal cross-sectional side view of a main part of an apparatus according to another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Sample holder, 2... Insulating material, 3... Sample, 4... Backscattered electron detection element, 12... Objective lens.

Claims (1)

[Claims] 1. A lid-shaped electron detection element with an opening in the center directly above the sample and an electron detection surface on the inside is attached to the upper edge of the sample holder that holds the sample and is taken in and out of the analyzer. A backscattered electron detector characterized in that it is installed in an insulated manner.