US-12618987-B2 - Radiation detection element, radiation detector, radiation detection device, and method for manufacturing radiation detection element

US12618987B2US 12618987 B2US12618987 B2US 12618987B2US-12618987-B2

Abstract

A radiation detection element includes: a semiconductor part including an incidence surface to which radiations to be detected are incident; a first electrode provided on the incidence surface; and a second electrode that is provided on the incidence surface and is disposed at a position surrounding the periphery of the first electrode. The radiation detection element is a silicon drift-type radiation detection element, and is provided with an insulating protective film that covers the second electrode.

Inventors

Koji Ishikura

Assignees

HORIBA, LTD.

Dates

Publication Date: 20260505
Application Date: 20220818
Priority Date: 20210825

Claims (11)

1 . A radiation detection element, comprising: a semiconductor part including an incidence surface to which radiations to be detected are incident; a first electrode provided on the incidence surface; a second electrode that is provided on the incidence surface and is disposed at a position surrounding the periphery of the first electrode; an oxide film that covers the incidence surface; and a metal electrode that extends through the oxide film and is connected to the second electrode, wherein the radiation detection element is a silicon drift-type radiation detection element, and the radiation detection element is provided with an insulating protective film that covers the oxide film and the metal electrode.
2 . The radiation detection element according to claim 1 , wherein the second electrode is an electrode configured to prevent dielectric breakdown between the first electrode and other portions.
3 . The radiation detection element according to claim 1 , further comprising: a metal film that overlaps the first electrode.
4 . The radiation detection element according to claim 1 , wherein the incidence surface includes an incidence region to which radiations to be detected are incident, the first electrode is provided in a region of the incidence surface which includes the incidence region, and the protective film does not overlap the incidence region.
5 . The radiation detection element according to claim 4 , wherein the oxide film covers the incidence region of the incidence surface and is disposed between the protective film and the semiconductor part in a region outside of the incidence region.
6 . A radiation detector, comprising: the radiation detection element according to claim 1 ; and a circuit board on which the radiation detection element is mounted.
7 . The radiation detector according to claim 6 , further comprising: a housing that accommodates the radiation detection element and the circuit board, wherein the housing includes an opening that is not blocked, and the radiation detection element is disposed with the incidence surface facing the opening.
8 . The radiation detector according to claim 6 , further comprising: a collimator that is disposed on the radiation detection element mounted on the circuit board; and a resin mold that covers a part of a surface of the collimator, a side surface of the collimator, a side surface of the radiation detection element, and a side surface of the circuit board, wherein the radiation detection element, the circuit board, the collimator, and the resin mold are not accommodated in the housing.
9 . A radiation detection device, comprising: an irradiation unit that irradiates a sample with radiations; the radiation detector according to claim 6 ; a spectrum generation unit that generates a spectrum of radiations detected by the radiation detector; and a display unit that displays the spectrum generated by the spectrum generation unit.
10 . A method for manufacturing a radiation detection element having a semiconductor part including an incidence surface including an incidence region to which radiations to be detected are incident, a first electrode that is provided in a region including the incidence region of the incidence surface, and a second electrode that is provided on the incidence surface and is disposed at a position surrounding the periphery of the first electrode, the method comprising: forming an insulating protective film that covers the first electrode and the second electrode; removing a portion of the protective film which overlaps the incidence region while leaving a portion of the protective film which covers the second electrode; and forming a metal film that overlaps the first electrode after removing the portion of the protective film which overlaps the incidence region.
11 . The method for manufacturing a radiation detection element according to claim 10 , wherein a metal layer that is connected to the first electrode is formed on the oxide film that overlaps the first electrode, the protective film is formed to overlap the metal layer, a portion of the protective film which overlaps the incidence region is removed while leaving the metal layer, a portion of the metal layer which overlaps the incidence region is removed after removing the portion of the protective film which overlaps the incidence region, and a metal film that overlaps the first electrode and the oxide film is formed after removing the portion of the metal layer which overlaps the incidence region.

Description

CROSS REFERENCE TO RELATED APPLICATION This Application is a 371 of PCT/JP2022/031152 filed on Aug. 18, 2022 which, in turn, claimed the priority of Japanese Patent Application No. 2021-137296 filed on Aug. 25, 2021, both applications are incorporated herein by reference. FIELD The present invention relates to a radiation detection element, a radiation detector, a radiation detection device, and a method for manufacturing a radiation detection element. BACKGROUND As a radiation detector that detects radiations such as X-rays, there is known a radiation detector including a radiation detection element using a semiconductor. A radiation detection element using a semiconductor has a plate-like shape, is mounted on a circuit board, and is disposed inside a housing provided in the radiation detector. The housing includes a window formed from a window material through which radiations are transmitted, and the radiation detection element is disposed so that one surface faces the window. The surface facing the window in the radiation detection element is an incidence surface to which the radiations are incident, and an electrode disposed on a rear surface of the incidence surface is covered with a protective film and is in contact with the circuit board through the protective film. International Publication WO 2019/117272 discloses a radiation detector which does not include the window formed from the window material and in which a portion corresponding to the window of the housing is opened. In the radiation detector, radiations with low energy are likely to be incident to the radiation detection element, and detection sensitivity of the radiations is improved. SUMMARY In the radiation detection element in the related art, an incidence surface is not covered with a protective film. Therefore, characteristics of the radiation detection element may fluctuate due to external influences from the outside such as adhesion of water to an electrode provided on the incidence surface. Particularly, a radiation detector which does not include a window and in which a housing is opened is susceptible to influences from the outside, and characteristics of the radiation detection element are likely to fluctuate. Due to fluctuation in the characteristics of the radiation detection element, accuracy of radiation detection using the radiation detector may be unstable. The disclosure has been made in consideration of such circumstances, and an object thereof is to provide a radiation detection element in which accuracy of radiation detection is stabilized, a radiation detector, a radiation detection device, and a method for manufacturing a radiation detection element. A radiation detection element according to an aspect of the present disclosure, is characterized by comprising: a semiconductor part including an incidence surface to which radiations to be detected are incident; a first electrode provided on the incidence surface; and a second electrode that is provided on the incidence surface and is disposed at a position surrounding the periphery of the first electrode, wherein the radiation detection element is a silicon drift-type radiation detection element, and the radiation detection element is provided with an insulating protective film that covers the second electrode. In an aspect of the present disclosure, in the radiation detection element, the second electrode that is disposed at a position surrounding the periphery of the first electrode provided on the incidence surface of the semiconductor part is covered with the insulating protective film. Foreign matters are less likely to adhere to the second electrode, and a fluctuation in the characteristics of the radiation detection element due to an influence of the adhered foreign matters is less likely to occur. In the radiation detection element according to an aspect of the present disclosure, it is characterized in that the second electrode is an electrode configured to prevent dielectric breakdown between the first electrode and other portions. In an aspect of the present invention, the second electrode that prevents dielectric breakdown between the first electrode and other portions is covered with the insulating protective film. A deterioration in the function of preventing the dielectric breakdown due to adhesion of foreign matters, and the fluctuation in the characteristics of the radiation detection element are prevented by the protective film. The radiation detection element according to an aspect of the present disclosure, is characterized by further comprising a metal film that overlaps the first electrode. In an aspect of the present disclosure, the metal film overlaps the first electrode. Suppression of contamination of a surface and light-shielding are performed by the metal film. In the radiation detection element according to an aspect of the present disclosure, it is characterized in that the incidence surface includes an incidence region to which radiatio