Photomultiplier tube, image sensor, and an inspection system using a PMT or image sensor
A system for inspecting a sample including a detector, either a photomultiplier tube or an electron-bombarded image sensor, that is positioned to receive light from the sample. The detector includes a semiconductor photocathode and a photodiode. Notably, the photodiode includes a p-doped semiconductor layer, an n-doped semiconductor layer formed on a first surface of the p-doped semiconductor layer to form a diode, and a pure boron layer formed on a second surface of the p-doped semiconductor layer. The semiconductor photocathode includes silicon, and further includes a pure boron coating on at least one surface.
1. A system for inspecting a sample, the system comprising:
a laser system for generating light;
first components for directing the light to the sample;
one or more detectors; and
second components for directing light from the sample to the one or more detectors,
wherein said one or more detectors include a photomultiplier tube, the photomultiplier tube comprising:
a semiconductor photocathode; and
a photodiode including:
a p-doped semiconductor layer;
a n-doped semiconductor layer formed on a first surface of the p-doped semiconductor layer to form a diode; and
a pure boron layer formed on a second surface of the p-doped semiconductor layer,
wherein the semiconductor photocathode comprises silicon, and
wherein the semiconductor photocathode further comprises a pure boron coating on at least one surface.
2. The system of claim 1 , wherein the semiconductor photocathode comprises a reflection-mode photocathode.
3. The system of claim 1 , wherein the semiconductor photocathode comprises a transmission-mode photocathode.
4. The system of claim 3 , wherein the photocathode further includes an anti-reflection layer.
5. The system of claim 1 , wherein the photomultiplier tube further comprises a window configured to admit the light directed from the sample to the one or more detectors, the window including a UV anti-reflection coating on at least one surface.
6. The system of claim 1 , wherein the first components are configured to direct the light to the sample at an oblique angle of incidence.
7. The system of claim 1 , wherein the at least one detector comprises two detectors configured such that a first detector is responsive to light scattered or reflected from the sample in a first direction, and a second detector is responsive to light scattered or reflected from the sample in a second direction, the second direction being different from the first direction.
8. A system for inspecting a sample, the system comprising:
a laser system for generating light;
first components for directing the light to the sample;
one or more detectors; and
second components for directing light from the sample to the one or more detectors,
wherein said one or more detectors include an electron-bombarded image sensor, the electron-bombarded image sensor comprising:
a semiconductor photocathode; and
a solid-state image sensor comprising:
a p-doped epitaxial semiconductor layer;
a gate dielectric layer formed on a first surface of the p-doped epitaxial semiconductor layer; and
a pure boron layer formed on exposed portions of a second surface of the p-doped epitaxial semiconductor layer,
wherein the semiconductor photocathode comprises silicon, and
wherein the semiconductor photocathode further comprises a pure boron coating on at least one surface.
9. The system of claim 8 , wherein the photocathode further includes an anti-reflection layer.
10. The system of claim 8 , wherein the electron-bombarded image sensor further comprises a window configured to admit the light directed from the sample to the one or more detectors, the window including a UV anti-reflection coating on at least one surface.
11. The system of claim 8 , wherein the first components are configured to direct the light to the sample at an oblique angle of incidence.
12. The system of claim 8 , wherein the at least one detector comprises two detectors configured such that a first detector is responsive to light scattered or reflected from the sample in a first direction, and the second detector is responsive to light scattered or reflected from the sample in a second direction, the second direction being different from the first direction.