X-ray sensor having a field limiting ring configuration

Patent metadata

Field	Value
Publication number	US-11888015-B2
Application number	US-201917610383-A
Country	US
Kind code	B2
Filing date	May 14, 2019
Priority date	May 14, 2019
Publication date	Jan 30, 2024
Grant date	Jan 30, 2024

Abstract

Disclosed is an X-ray sensor having an active detector region including detector diodes on its surface. The X-ray sensor further includes a junction termination surrounding the surface region including the detector diodes. The junction termination includes a guard arranged closest to the end of the surface region, a field stop outside the guard and at least two field limiting rings, FLRs arranged between the guard and the field stop. A first FLR is arranged at a distance Δ 1 from the guard selected from the interval [4 μm; 12 μm], a second FLR is arranged at a distance Δ 2 from the first FLR selected from the interval [6.5 μm; 14 μm], and wherein the distance Δ 2 is larger than the distance Δ 1 . The proposed technology also provides a method for constructing such an X-ray sensor and an X-ray imaging system including an X-ray detector system that includes such X-ray sensor.

First claim

The invention claimed is:

1. An X-ray sensor having an active detector region comprising a plurality of detector diodes arranged on a surface region of the X-ray sensor, said X-ray sensor further comprising a junction termination surrounding said surface region comprising said plurality of detector diodes, said junction termination comprising a guard arranged closest to the end of said surface region, a field stop arranged outside said guard and at least two field limiting rings, FLRs arranged between said guard and said field stop, wherein a first FLR is arranged at a distance Δ 1 from the guard selected from the interval [4 μm; 12 μm], and a second FLR is arranged at a distance Δ 2 from the first FLR selected from the interval [6.5 μm; 15 μm] and wherein the distance Δ 2 is larger than the distance Δ 1 .

2. The x-ray sensor according to claim 1 , wherein said distance Δ 1 is 10±0.5 μm, said distance Δ 2 is 13±0.5 μm.

3. The x-ray sensor according to claim 1 , wherein said junction termination comprises at least three FLRs, a first FLR arranged at a distance Δ 1 from the guard selected from the interval [7 μm; 11 μm], a second FLR is arranged at a distance Δ 2 from the first FLR selected from the interval [10 μm; 14 μm], and a third FLR that is arranged at a distance Δ 3 from the second FLR selected from the interval [13 μm; 17 μm], and wherein the distance Δ 3 is larger than the distance Δ 2 .

4. The x-ray sensor according to claim 3 , wherein said distance Δ 1 is 9±0.5 μm, said distance Δ 2 is 12±0.5 μm, and said distance Δ 3 is 15±0.5 μm.

5. The x-ray sensor according to claim 1 , wherein said junction termination comprises at least four FLRs, a first FLR arranged at a distance Δ 1 from the guard selected from the interval [6 μm; 10 μm], a second FLR is arranged at a distance Δ 2 from the first FLR selected from the interval [9 μm; 13 μm], a third FLR is arranged at a distance Δ 3 from the second FLR selected from the interval [12 μm; 16 μm] and a fourth FLR arranged at a distance Δ 4 from the third FLR selected from the interval [15 μm; 19 μm], and wherein the distance Δ 2 is larger than the distance Δ 1 , the distance Δ 3 is larger than the distance Δ 2 , and the distance Δ 4 is larger than the distance Δ 3 .

6. The x-ray sensor according to claim 5 , wherein said distance Δ 1 is 8±0.5 μm, said distance Δ 2 is 11±0.5 μm, said distance Δ 3 is 14±0.5 μm and said fourth distance Δ 4 is 17±0.5 μm.

7. The X-ray sensor according to claim 1 , wherein the junction termination comprises at least five FLRs, a first FLR arranged at a distance Δ 1 from the guard selected from the interval [5 μm; 9 μm], a second FLR arranged at a distance Δ 2 from the first FLR selected from the interval [8 μm; 12 μm], a third FLR arranged at a distance Δ 3 from the second FLR selected from the interval [10.5 μm; 14.5 μm], a fourth FLR arranged at a distance Δ 4 from the third FLR selected from the interval [13.5 μm; 17.5 μm], and a fifth FLR arranged at a distance Δ 5 from the fourth FLR selected from the interval [16 μm; 20 μm], and wherein the distance Δ 2 is larger than the distance Δ 1 , the distance Δ 3 is larger than the distance Δ 2 , the distance Δ 4 is larger than the distance Δ 3 and the distance Δ 5 is larger than the distance Δ 4 .

8. The x-ray sensor according to claim 7 , wherein said distance Δ 1 is 7±0.5 μm, said distance Δ 2 is 10±0.5 μm, said distance Δ 3 is 12.5±0.5 μm, said fourth distance Δ 4 is 15.5±0.5 μm and said distance Δ 5 is 18±0.5.

9. The X-ray sensor according to claim 1 , wherein said junction termination comprises six FLRs, a first FLR arranged at a distance Δ 1 from the guard selected from the interval [4 μm; 8 μm], a second FLR arranged at a distance Δ 2 from the first FLR from the interval [6.5 μm; 10.5 μm], a third FLR arranged at a distance Δ 3 from the second FLR selected from the interval [9 μm; 13 μm], a fourth FLR arranged at a distance Δ 4 from the third FLR selected from the interval [11.5 μm; 15.5 μm], a fifth FLR arranged at a distance Δ 5 from the fourth FLR selected from the interval [14 μm; 18 μm] and a sixth FLR arranged at a distance Δ 6 from the fifth FLR selected from the interval [17 μm; 21 μm] and wherein the distance Δ 2 is larger than the distance Δ 1 , the distance Δ 3 is larger than the distance Δ 2 , the distance Δ 4 is larger than the distance Δ 3 , the distance Δ 5 is larger than the distance Δ 4 and the distance Δ 6 is larger than the distance Δ 5 .

10. The X-ray sensor according to claim 9 , wherein said distance Δ 1 is 6±0.5 said distance Δ 2 is 8.5±0.5 said distance Δ 3 is 11±0.5 said distance Δ 4 is 13.5±0.5 μm said distance Δ 5 is 16±0.5 μm and said distance Δ 6 is 19±0.5 μm.

11. The X-ray sensor according to claim 1 , wherein the active detector region comprises a doped material having a doping concentration in the interval 1×10 10 cm −3 to 1×10 12 cm −3 .

12. The X-ray sensor according to claim 1 , wherein the active detector region comprises a doped silicon, having the opposite type of doping as the field limiting rings.

13. The X-ray sensor according to claim 1 , wherein the distance between the detector diode closest to the guard and the guard is selected to lie in the interval [20 μm; 30 μm].

14. The X-ray sensor according to claim 1 , wherein the distance between the FLR closest to the field stop and the field stop is selected from the interval [20 μm; 50 μm].

15. An X-ray imaging system comprising:
an X-ray source configured to emit X-rays;
an X-ray detector system comprising at least one X-ray sensor according to claim 1 ; and
an image processing device.

16. A method for constructing an X-ray sensor, said method comprises the steps of:
providing a plurality of detector diodes on a surface region of a material substrate;
providing said material substrate with a junction termination surrounding said surface region; wherein said junction termination is constructed by:
providing a guard adjacent said surface region;
providing a field stop outside of said guard;
arranging at least two field limiting rings, FLRs between said guard and said field stop, where a first FLR is arranged at a distance Δ 1 from the guard selected from the interval [4 μm; 12 μm], a second FLR is arranged at a distance Δ 2 from the first FLR selected from the interval [6.5 μm; 15 μm], wherein the distance Δ 2 is larger than the distance Δ 1 .

17. A method according to claim 16 , wherein the step of arranging said at least two FLRs further comprises to arrange said first FLR at a distance Δ 1 given by 10±0.5 μm, and arranging said second FLR at a distance Δ 2 from the first FLR given by 13±0.5 μm.

18. A method according to claim 16 , wherein the step of arranging said at least two FLRs comprises to arrange at least three FLRs, a first FLR at a distance Δ 1 from the guard selected from the interval [7 μm; 11 μm], a second FLR at a distance Δ 2 from the first FLR selected from the interval [10 μm; 14 μm], and a third FLR at a distance Δ 3 from the second FLR selected from the interval [13 μm; 17 μm], wherein the distance Δ 3 is larger than the distance Δ 2 .

19. A method according to claim 18 , wherein the step of arranging said at least three FLRs further comprises to arrange said first FLR at a distance Δ 1 given by 9±0.5 μm, arranging said second FLR at a distance Δ 2 from the first FLR given by 12±0.5 μm, and arranging said third FLR at a distance Δ 3 from the second FLR given by 15±0.5 μm.

20. A method according to claim 16 , wherein t

Assignees

• Prismatic Sensors Ab

Inventors

• Bakowski Holtryd Mietek
• Danielsson Mats
• Xu Cheng

Classifications

• H10F39/802

  Geometry or disposition of elements in pixels, e.g. address-lines or gate electrodes · CPC title

• H10F39/80

  Constructional details of image sensors · CPC title

• H10F39/011

  Manufacture or treatment of image sensors covered by group H10F39/12 · CPC title

• H10F39/189 Primary

  X-ray, gamma-ray or corpuscular radiation imagers · CPC title

• H01L27/14658 Primary

  Electricity · mapped topic