Photocathode including silicon substrate with boron layer
AssigneeKLA-Tencor Corporation
InventorsYung-Ho Alex Chuang, John Fielden
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Abstract
A photocathode is formed on a monocrystalline silicon substrate having opposing illuminated (top) and output (bottom) surfaces. To prevent oxidation of the silicon, a thin (e.g., 1-5 nm) boron layer is disposed directly on the output surface using a process that minimizes oxidation and defects. An optional second boron layer is formed on the illuminated (top) surface, and an optional anti-reflective material layer is formed on the second boron layer to enhance entry of photons into the silicon substrate. An optional external potential is generated between the opposing illuminated (top) and output (bottom) surfaces. The photocathode forms part of novel electron-bombarded charge-coupled device (EBCCD) sensors and inspection systems.
Claims18
A transmission photocathode comprising:
- a silicon substrate having opposing first and second surfaces;
- and
- a first layer consisting essentially of boron disposed directly on the second surface of the silicon substrate,
- a second layer consisting essentially of boron disposed directly on the first surface of the silicon substrate,
- wherein the transmission photocathode is configured to absorb photons that enter the silicon substrate through the first surface such that photo-electrons are generated in response to said absorbed photons, and to emit said photo-electrons through the second surface and through the first layer.
A transmission photocathode comprising:
- a silicon substrate having opposing illuminated and output surfaces;
- and
- a first layer consisting essentially of boron disposed directly on the output surface of the silicon substrate,
- a second layer consisting essentially of boron disposed directly on the first surface of the silicon substrate,
- wherein a thickness of said silicon substrate between said illuminated and output surfaces and a dopant concentration of said silicon substrate are configured such that said silicon substrate generates photo-electrons in response to photons that enter said silicon substrate through the illuminated surface, and such that said generated photo-electrons are emitted said through the output surface.
A photocathode comprising:
- a silicon substrate having opposing first and second surfaces;
- a first layer consisting essentially of boron disposed directly on the second surface of the silicon substrate, and
- a second layer consisting essentially of boron disposed directly on the first surface of the silicon substrate,
- wherein the first and second layers comprise pin-hole free boron layers having respective thicknesses in the range of 1-5 nm.
Dependencies are inferred from the claim text.