US-12628446-B2 - Integrated detector device and method of manufacturing an integrated detector device

US12628446B2US 12628446 B2US12628446 B2US 12628446B2US-12628446-B2

Abstract

An integrated detector device for direct detection of X-ray photons includes a CMOS body including a substrate portion and a dielectric portion arranged on a main surface of the substrate portion, an integrated circuit in the CMOS body having implants at or above the main surface for forming charge collectors, and a metal structure in the dielectric portion that extends from the charge collectors to a contact surface of the dielectric portion facing away from the substrate portion. The device further includes an absorber portion arranged on the contact surface of the dielectric portion, the absorber portion including an absorber element that is in electrical contact with the metal structure, and an electrode structure that is in direct contact with the absorber element forming an electrical contact. The absorber element is configured to absorb X-ray photons and generate electrical charges based on the absorbed X-ray photons.

Inventors

Jens Hofrichter

Assignees

AMS INTERNATIONAL AG

Dates

Publication Date: 20260512
Application Date: 20211118
Priority Date: 20201204

Claims (16)

1 . An integrated detector device for direct detection of X-ray photons, the integrated detector device comprising: a CMOS body comprising a substrate portion and a dielectric portion arranged on a main surface of the substrate portion; an integrated circuit in the CMOS body having implants at or above the main surface for forming charge collectors; a metal structure in the dielectric portion that extends from the charge collectors to a contact surface of the dielectric portion facing away from the substrate portion; an absorber portion arranged on the contact surface of the dielectric portion, the absorber portion comprising an absorber element that is in electrical contact with the metal structure; and an electrode structure that is in direct contact with the absorber element forming an electrical contact, wherein the absorber element is configured to absorb X-ray photons and generate electrical charges based on the absorbed X-ray photons; a material of the absorber element is a metal-halide perovskite, in particular, an inorganic metal-halide perovskite such as CsPbBr 3 , and the metal structure is either a via structure or a metallization level present in the backend-of-line, and/or a material of the metal structure at the contact surface is a catalyst acting as a nucleation site of a material of the absorber element or its educts.
2 . The integrated detector device according to claim 1 , wherein the integrated detector device is a monolithic semiconductor device.
3 . The integrated detector device according to claim 1 , wherein a material of the metal structure at the contact surface is a catalyst with respect to a reaction educt of a material of the absorber element.
4 . The integrated detector device according to claim 1 , wherein the absorber element is in direct physical contact with the contact surface.
5 . The integrated detector device according to claim 1 , wherein the absorber portion further comprises a passivation that at least partially surrounds the absorber element and an electrode of the electrode structure is arranged on a surface of the passivation facing away from the contact surface.
6 . The integrated detector device according claim 1 , wherein the contact surface comprises first bond pads and the absorber portion comprises a bonding surface having second bond pads that are in electrical contact with the absorber element; and the first bond pads are bonded to the second bond pads via a direct bonding process.
7 . The integrated detector device according to claim 1 , wherein the integrated detector device is free of connecting elements such as solder bumps between the CMOS body and the absorber portion.
8 . The integrated detector device according to claim 1 , wherein the integrated detector device is free of CdTe and CdZnTe.
9 . A method of manufacturing an integrated detector device for direct detection of X-ray photons, the method comprising: forming a CMOS body by arranging a dielectric portion on a main surface of a substrate portion; forming an integrated circuit in the CMOS body having implants at or above the main surface for forming charge collectors; forming a metal structure in the dielectric portion that extends from the charge collectors to a contact surface of the dielectric portion facing away from the substrate portion; arranging an absorber portion on the contact surface of the dielectric portion by forming an absorber element that is in electrical contact with the metal structure; providing an electrode structure that is in direct contact with the absorber element forming an electric contact, wherein the absorber element is configured to absorb X-ray photons and generate electrical charges based on the absorbed X-ray photons; and a material of the absorber element is a metal-halide perovskite, in particular an inorganic metal-halide perovskite such as CsPbBr 3 ; and forming the metal structure comprises providing a via structure having a top via made of tungsten at the contact surface, and/or forming the absorber element comprises patterning, structuring and/or polishing of a material of the absorber element.
10 . The method according to claim 9 , wherein arranging the absorber portion further comprises forming a passivation that at least partially surrounds the absorber element; and providing the electrode structure comprises arranging an electrode on a surface of the passivation facing away from the contact surface.
11 . The method according to claim 9 , wherein arranging the absorber portion comprises growing, in particular selectively growing, a material of the absorber element on the contact surface, wherein a region of the metal structure at the contact surface acts as a nucleation site.
12 . The method according to claim 9 , wherein arranging the absorber portion comprises performing a direct bonding process between the absorber portion and the CMOS body.
13 . The method according to claim 9 , wherein the manufacturing method is a fully CMOS compatible process.
14 . The method according to claim 9 , wherein arranging the absorber portion comprises depositing a dielectric layer on the contact surface; patterning and structuring the dielectric layer to form a trench within the dielectric layer; and depositing the absorber element within the trench.
15 . The method according to claim 9 , wherein a material of the metal structure at the contact surface is a catalyst acting as a nucleation site of a material of the absorber element or its educts.
16 . An integrated detector device for direct detection of X-ray photons, the integrated detector device comprising: a CMOS body comprising a substrate portion and a dielectric portion arranged on a main surface of the substrate portion; an integrated circuit in the CMOS body having implants at or above the main surface for forming charge collectors; a metal structure in the dielectric portion that extends from the charge collectors to a contact surface of the dielectric portion facing away from the substrate portion; an absorber portion arranged on the contact surface of the dielectric portion, the absorber portion comprising an absorber element that is in electrical contact with the metal structure; and an electrode structure that is in direct contact with the absorber element forming an electrical contact, wherein the absorber element is configured to absorb X-ray photons and generate electrical charges based on the absorbed X-ray photons, a material of the absorber element is a metal-halide perovskite, in particular, an inorganic metal-halide perovskite such as CsPbBr 3 , and the absorber portion further comprises a passivation that at least partially surrounds the absorber element and an electrode of the electrode structure is arranged on a surface of the passivation facing away from the contact surface.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is the national stage entry of International Patent Application No. PCT/EP2021/082118, filed on Nov. 18, 2021, and published as WO 2022/117354 A1 on Jun. 9, 2022, which claims priority to German Application No. 10 2020 132 323.9, filed on Dec. 4, 2020, the disclosures of all of which are incorporated by reference herein in their entireties. FIELD OF THE INVENTION This disclosure relates to integrated detector devices for direct detection of X-ray photons and to a manufacturing method of such detector devices. BACKGROUND OF THE INVENTION State of the art computed tomography, CT, scanners employ scintillators to absorb and convert X-rays that carry medical diagnostic information, for example, to visible light quanta. This visible photons are then, in a second step, detected by conventional silicon photodiodes producing an electrical current. Using the scintillator approach, however, makes it impossible to perform X-ray photon counting, e.g., for determining the X-ray energy spectrum. Direct detectors, on the other hand, where the X-ray photons are directly detected and transformed into charge without involving scintillators and the conversion to visible light, provide a significantly enhanced spatial resolution, and more importantly, also the capability to resolve the energy of the detected X-ray photons. Moreover, it is desirable that the detectors are fast such as to enable photon counting. Typical decay times are less than 1 microsecond. Some detectors have response times of 100 nanoseconds or less. Most direct detectors are based on absorbing materials such as CdTe or CdZnTe. However, these materials are very challenging to grow and thus are typically characterized by small yields in the order of 10%. Moreover, due to brittleness and susceptibility to thermal shock, integration of these materials require low temperature assembly processes. These downsides limit not only the flexibility in the assembly process, but also the integration density, the choice of material, as well as the readout speed due to parasitics. It is an object to provide an improved concept of integrated detector devices for direct detection of X-ray photons and their manufacturing that overcome the limitations of existing detectors. This object is achieved with the subject-matter of the independent claims. Further aspects of the improved concept are the subject-matter of the dependent claims. SUMMARY OF THE INVENTION The improved concept is based on the idea of tightly integrating the direct detection elements onto the backend of line of the readout integrated circuit without employing wire bonds or bumps between the direct detection element and the readout circuit. In particular, the improved concept allows for the use of high temperature assembly steps in excess of 100° C. Furthermore, the improved concept enables photon counting via the improved direct interconnect concept between absorber and back-end-of-line, realizing sufficiently fast direct detection with response times of 100 ns or less. An integrated detector device for direct detection of X-ray photons according to the improved concept comprises a CMOS body comprising a substrate portion and a dielectric portion that are arranged on a main surface of the substrate portion. The integrated detector device further comprises an integrated circuit in the CMOS body having implants at or above the main surface for forming charge collectors. Furthermore, a metal structure in the dielectric portion extends from the charge collectors to a contact surface of the dielectric portion facing away from the substrate portion, and an absorber portion is arranged on the contact surface of the dielectric portion, wherein the absorber portion comprises an absorber element that is in electrical contact with the metal structure. The integrated detector device further comprises an electrode structure that is in direct contact with the absorber element forming an electrical contact. The absorber element is configured to absorb X-ray photons and generate electrical charges based on the absorbed X-ray photons. Throughout this disclosure, the terms X-ray radiation and X-ray photons refer to high-energy ionizing electromagnetic radiation with an energy in excess of 100 eV up to about 150 keV. This translates to wavelengths of X-ray photons ranging from 10 pm to 10 nm. The dielectric portion of the CMOS body can be a back-end of line (BEOL) of the detector device that is arranged on a substrate, e.g., a silicon wafer or a chip. The CMOS body comprises a readout integrated circuit for reading out electrical charges formed within the absorber element and providing an electrical signal based on the electrical charges to a processor unit for further processing. Therein, the dielectric portion comprises a layer of a dielectric, such as a silica that comprises a metal structure that can either be a via structure formed from vias and metal interco