# US 8,785,862 B2 · X-ray detector and medical X-ray device

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- Number: US 8,785,862 B2
- Document ID: US8785862B2
- Status: Granted
- Kind: B2
- Application number: 13/408,560
- Filed: 2012-02-29
- Published: 2012-09-06
- Granted: 2014-07-22
- Earliest claimed: 2011-03-02
- Assignees: Siemens Aktiengesellschaft
- Applicants: Michael Stark
- Inventors: Michael Stark
- Web page: https://patentgrep.com/patent/US8785862B2

## CPC

- G01T 1/1642: {using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras}
- G01T 1/2018: {Scintillation-photodiode combinations}
- G01T 1/24: with semiconductor detectors
- H10F 39/189: {X-ray, gamma-ray or corpuscular radiation imagers}
- H10F 39/802: {Geometry or disposition of elements in pixels, e.g. address-lines or gate electrodes}
- A61B 6/487: {involving fluoroscopy}
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

An X-ray detector having an active array comprising pixel elements for detecting X-ray radiation is provided to enable high-quality X-ray imaging, wherein each pixel element has a scintillator layer for converting X-ray radiation into light and a photodiode produced by means of CMOS technology for converting light into a measurable electrical signal, and wherein the pixel elements are arranged on a silicon substrate and a BOX (buried oxide) layer is sandwiched between the silicon substrate and the photodiode.

## Claims

### Claim 1

An X-ray detector comprising:
an active array of pixel elements for detecting X-ray radiation,
wherein each pixel element has a scintillator layer for converting X-ray radiation into light and a photodiode produced by means of CMOS technology for converting light into a measurable electrical signal, and
wherein the pixel elements are arranged on a silicon substrate and a buried oxide layer is sandwiched between the silicon substrate and the photodiode, the buried oxide layer being sized and configured to prevent X-ray-induced charges generated in the substrate from diffusing to the photodiode.

### Claim 2 (depends on 1)

The X-ray detector of claim 1, wherein the photodiode is embedded in an epitaxial silicon layer.

### Claim 3 (depends on 2)

The X-ray detector of claim 2, wherein the thickness of the epitaxial silicon layer corresponds to the wavelength of the light that can be generated in the scintillator layer.

### Claim 4 (depends on 3)

The X-ray detector of claim 3, wherein the thickness of the epitaxial silicon layer is selected such that between 90% and 98% of the light generated by the scintillator layer can be absorbed.

### Claim 5 (depends on 4)

The X-ray detector of claim 4, wherein the thickness of the epitaxial silicon layer is selected such that about 95% of the light generated by the scintillator layer can be absorbed.

### Claim 6 (depends on 1)

The X-ray detector of claim 1, wherein the buried oxide layer has a thickness of between 40 nm and 100 nm.

### Claim 7 (depends on 1)

The X-ray detector of claim 1, wherein the active array is embodied as an active pixel sensor.

### Claim 8

A medical X-ray device, comprising:
an X-ray source, and
an X-ray detector comprising:
an active array of pixel elements for detecting X-ray radiation,
wherein each pixel element has a scintillator layer for converting X-ray radiation into light and a photodiode produced by means of CMOS technology for converting light into a measurable electrical signal, and
wherein the pixel elements are arranged on a silicon substrate and a buried oxide layer is sandwiched between the silicon substrate and the photodiode, the buried oxide layer being sized and configured to prevent X-ray-induced charges generated in the substrate from diffusing to the photodiode.

### Claim 9 (depends on 8)

The X-ray device of claim 8, wherein the photodiode is embedded in an epitaxial silicon layer.

### Claim 10 (depends on 9)

The X-ray device of claim 9, wherein the thickness of the epitaxial silicon layer corresponds to the wavelength of the light that can be generated in the scintillator layer.

### Claim 11 (depends on 10)

The X-ray device of claim 10, wherein the thickness of the epitaxial silicon layer is embodied in such a way that between 90% and 98% of the light generated by the scintillator layer can be absorbed.

### Claim 12 (depends on 11)

The X-ray device of claim 11, wherein the thickness of the epitaxial silicon layer is selected such that about 95% of the light generated by the scintillator layer can be absorbed.

### Claim 13 (depends on 8)

The X-ray device of claim 8, wherein the buried oxide layer has a thickness of between 40 nm and 100 nm.

### Claim 14 (depends on 8)

The X-ray device of claim 8, wherein the active array is embodied as an active pixel sensor.