Image intensifier with thin layer transmission layer support structures
View Patent ↗A light intensifier includes a semiconductor structure to multiply electrons and block stray particles. A thin gain substrate layer includes an electron multiplier region that is doped to generate a plurality of electrons for each electron that impinges on an input surface of the gain substrate layer and blocking structures that are doped to direct the plurality of electrons towards emission areas of an emission surface of the gain substrate layer. Respective ribs of a first plurality of ribs on the input surface of the gain substrate layer are vertically aligned with respective blocking structures, and respective blocking structures are vertically aligned with respective ribs of a second plurality of ribs at the emission surface. This alignment directs electrons along a path through the gain substrate layer to reduce noise. The support ribs provide mechanical strength to the gain substrate layer, improving robustness of the light intensifier while minimizing noise.
1. An apparatus, comprising:
a semiconductor structure that includes:
a gain substrate layer doped to generate a plurality of electrons for each received electron that impinges on an input surface of the gain substrate layer;
a first plurality of ribs disposed at an input surface of the gain substrate layer;
a blocking structure disposed within the gain substrate layer that is doped to repel the plurality of electrons towards an emission area of an emission surface of the gain substrate layer;
a shielding region doped to absorb stray particles that impinge on the emission surface of the gain substrate layer, wherein the stray particles include one or more of stray photons and stray ions; and
a second plurality of ribs disposed at the emission surface of the gain substrate layer.
2. The apparatus of claim 1 , wherein:
each rib of the first plurality of ribs is vertically aligned with respective ribs of the second plurality of ribs.
3. The apparatus of claim 1 , wherein:
each rib of the first plurality of ribs is vertically aligned with a respective blocking structure and with a respective rib of the second plurality of ribs that direct electrons along a respective channel through the gain substrate layer.
4. The apparatus of claim 1 , wherein:
a gap distance between a photocathode and the first plurality of ribs is between about 100-500 μm.
5. The apparatus of claim 1 , wherein:
the shielding region is doped to convert the stray particles to respective pairs of stray electrons and stray holes, and to recombine the stray electrons with the stray holes.
6. The apparatus of claim 1 , wherein:
blocking structures and a background region are doped with a p-type dopant, wherein the blocking structure is more highly doped than the background region of the gain substrate layer; and
the shielding region is doped with an n-type dopant.
7. The apparatus of claim 1 , wherein:
the blocking structure extends from the emission surface of the gain substrate layer towards the input surface of the gain substrate layer; and
the shielding region is within the blocking structure.
8. The apparatus of claim 1 , wherein:
the gain substrate layer includes a plurality of blocking structures, each doped to repel the plurality of electrons towards respective adjacent emission areas of the emission surface of the gain substrate layer; and
each blocking structure includes a shielding region disposed next to the emission surface, with each shielding region doped to absorb stray particles that impinge the emission surface of the gain substrate layer; and
the second plurality of ribs surround the emission areas.
9. The apparatus of claim 1 , wherein:
the gain substrate layer comprises channels that extend from the emission surface of the gain substrate layer toward the input surface of the gain substrate layer; and
a width of the channel is greater at the input surface than at the emission surface.
10. The apparatus of claim 9 , comprising:
multiple rows of channels including first rows and second rows, wherein the first rows of channels are perpendicular to the second rows of blocking channels.
11. The apparatus of claim 1 , wherein:
the gain substrate layer is configured as an array of cells configured similar to each another; and
a first cell of the array of cells includes the blocking structure, the shielding region, and the emission area.
12. The apparatus of claim 1 , wherein:
the emission surface of the gain substrate layer includes a 2-dimensional array of blocking structures;
the emission surface includes a 2-dimensional array of emission areas, each emission area within a respective one of the blocking structures; and
the shielding region encompasses a remaining portion of the emission surface, and wherein the second plurality of ribs are disposed on the shielding region.
13. The apparatus of claim 1 , further including:
a photocathode to convert photons to electrons and to direct the electrons toward the input surface of the gain substrate layer; and
an anode to receive the plurality of electrons from the semiconductor structure.
14. A method, comprising:
generating a plurality of electrons for a received electron that impinges on an input surface of a gain substrate layer within an electron multiplier region of the gain substrate layer, wherein a first plurality of ribs is disposed at the input surface of the gain substrate layer and a second plurality of ribs is disposed at an emission surface of the gain substrate layer to provide mechanical strength to the gain substrate layer;
repelling the plurality of electrons from blocking structures of the gain substrate layer that are doped to repel electrons, towards emissions areas of an emission surface of the gain substrate layer; and
absorbing stray particles that impinge on the emission surface of the gain substrate layer within shielding regions of the gain substrate layer that are doped to absorb photons, wherein the stray particles include one or more of stray photons and stray ions.
15. The method of claim 14 , further comprising:
fabricating the first plurality of ribs and the second plurality of ribs such that respective ribs of the first plurality of ribs are vertically aligned with respective ribs of the second plurality of ribs.
16. The method of claim 14 , further comprising:
fabricating the first plurality of ribs, blocking structures, and the second plurality of ribs such that respective ribs of the first plurality of ribs are vertically aligned with respective blocking structures, and respective blocking structures are vertically aligned with respective ribs of the second plurality of ribs; and
directing a flow of electrons along a respective channel through the gain substrate layer.
17. The method of claim 14 , further comprising:
doping blocking structures and a background region with a p-type dopant, wherein the blocking structures are more highly doped than the background region of the gain substrate layer; and
doping the shielding regions with an n-type dopant.
18. The method of claim 17 , further comprising:
doping each of a plurality of blocking structures in the gain substrate layer to repel the plurality of electrons towards respective adjacent emission areas of the emission surface of the gain substrate layer;
doping each shielding region disposed next to the emission surface, to absorb stray particles that impinge emission areas of the gain substrate layer; and
surrounding the emission areas with the second plurality of ribs.
19. The method of claim 18 wherein:
a plurality of blocking regions include multiple rows of blocking channels that extend from the emission surface of the gain substrate layer toward the input surface of the gain substrate layer.
20. The method of claim 14 , wherein:
the emission surface of the gain substrate layer includes a 2-dimensional array of blocking structures;
the emission surface includes a 2-dimensional array of emission areas, each emission area within a respective one of the blocking structures; and
the shielding region encompasses a remaining portion of the emission surface, and wherein the second plurality of ribs are disposed on the shielding region.