X-ray detector and method for forming the same
The present disclosure relates to an X-RAY detector including a base substrate and a plurality of detection units arranged on the base substrate. Each detection unit includes a light conversion element and a switching transistor, the light conversion element is configured to convert an optical signal into an electrical signal, and the switching transistor is configured to output the electrical signal to a reading signal line. Each detection unit further includes a radiation shielding structure located at a light-entering side of the detection unit, and an orthogonal projection of the radiation shielding structure onto the base substrate fully covers an orthogonal projection of the switching transistor onto the base substrate. The present disclosure further relates to a method for forming the X-RAY detector.
1. An X-RAY detector, comprising a base substrate and a plurality of detection units arranged on the base substrate, wherein each detection unit comprises a light conversion element for converting an optical signal into an electrical signal and a switching transistor for outputting the electrical signal to a reading signal line, wherein each detection unit further comprises a radiation shielding structure located at a light-entering side of the detection unit, and an orthogonal projection of the radiation shielding structure onto a plane where the base substrate is located fully covers an orthogonal projection of the switching transistor onto the plane where the base substrate is located; wherein the plane where the base substrate is located is perpendicular to a direction from the light-entering side of the base substrate to a light-exiting side of the base substrate;
wherein the switching transistor and the light conversion element are located at two opposite sides of the base substrate respectively, a via hole is provided in the base substrate, and the switching transistor is coupled to the light conversion element through the via hole.
2. The X-RAY detector according to claim 1 , wherein the light conversion element is located at the light-entering side of the base substrate, the switching transistor is located at the light-exiting side of the base substrate, and the radiation shielding structure is arranged between the light conversion element and the base substrate, or between the base substrate and the switching transistor.
3. The X-RAY detector according to claim 2 , wherein the radiation shielding structure is a planar structure arranged on the base substrate in an entire layer manner, and the via hole is provided penetrating the base substrate and the radiation shielding structure.
4. The X-RAY detector according to claim 2 , wherein the radiation shielding structure comprises a patterning shielding layer, and the patterning shielding layer comprises a light-shielding region corresponding to the switching transistor, and a light-transmitting region located outside the light-shielding region.
5. The X-RAY detector according to claim 1 , wherein the light conversion element comprises a first electrode, a direct conversion material layer and a second electrode laminated one on another sequentially in a direction away from the base substrate;
or, the light conversion element is a PIN diode or an NIP diode or an Avalanche Photo Diode (APD).
6. The X-RAY detector according to claim 1 , wherein the light conversion element is a PIN diode or an NIP diode.
7. The X-RAY detector according to claim 1 , wherein the switching transistor is of a bottom-gate structure, a top-gate structure or a Complementary Metal Oxide Semiconductor (CMOS) structure.
8. The X-RAY detector according to claim 1 , wherein each detection unit further comprises an X-RAY conversion layer arranged at the light-entering side of the detection unit, and the X-RAY conversion layer is configured to convert X rays into a visible optical signal.
9. A method for forming the X-RAY detector according to claim 1 , comprising:
forming a radiation shielding layer on a base substrate; and
forming a light conversion element and a switching transistor at opposite sides of the base substrate respectively;
wherein the forming the light conversion element and the switching transistor at opposite sides of the base substrate respectively, comprises:
forming the switching transistor at a light-exiting side of the base substrate;
forming a via hole in the base substrate penetrating the base substrate and the radiation shielding layer; and
forming the light conversion element at a side of the radiation shielding layer away from the base substrate, wherein the light conversion element is coupled to the switching transistor through the via hole.
10. The method according to claim 9 , wherein prior to forming the switching transistor at the light-exiting side of base substrate, the method further comprises:
forming a first connection metal layer at the light-exiting side of the base substrate, wherein the first connection metal layer is coupled to a source electrode of the switching transistor;
prior to the forming the light conversion element at the side of the radiation shielding layer away from the base substrate, the method further comprises:
forming a second connection metal layer at the side of the radiation shielding layer away from the base substrate, wherein the second connection metal layer is coupled to the first connection metal layer through the via hole.
11. The X-RAY detector according to claim 1 , wherein the switching transistor is of a bottom-gate structure, a top-gate structure or a Complementary Metal Oxide Semiconductor (CMOS) structure.