Method of manufacturing a spectral filter for green and shorter wavelengths
First Claim
1. A method of making a spectral filter comprising:
- providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface,etching the substrate wafer to provide a structured macroporous layer having pores with controlled depths defined at least partially therethrough,coating the pores wit at least one layer of a material substantially transparent within the pass-band of said spectral filter, said material having a thickness of at least 10 nm, andremoving at least one un-etched portion of the substrate wafer to thereby provide a spectral filter.
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Accused Products
Abstract
The UV, deep UV and/or far UV (ultraviolet) filter transmission spectrum of an MPSi spectral filter is optimized by introducing at least one layer of substantially transparent dielectric material on the pore walls. Such a layer will modify strongly the spectral dependences of the leaky waveguide loss coefficients through constructive and/or destructive interference of the leaky waveguide mode inside the layer. Increased blocking of unwanted wavelengths is obtained by applying a metal layer to one or both of the principal surfaces of the filter normal to the pore directions. The resulting filters are stable, do not degrade over time and exposure to UV irradiation, and offer superior transmittance for use as bandpass filters. Such filters are useful for a wide variety of applications including but not limited to spectroscopy and biomedical analysis systems.
17 Citations
41 Claims
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1. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, etching the substrate wafer to provide a structured macroporous layer having pores with controlled depths defined at least partially therethrough, coating the pores wit at least one layer of a material substantially transparent within the pass-band of said spectral filter, said material having a thickness of at least 10 nm, and removing at least one un-etched portion of the substrate wafer to thereby provide a spectral filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 41)
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21. A method of making a spectral filter, said method comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, etching the substrate wafer to provide a macroporous structured layer having pores with controlled depths defined at least partially therethrough, removing at least one un-etched part of the substrate wafer, and coating the pores with at least one layer of a material substantially transparent within the pass-band of said spectral filter material and having a thickness of at least 10 nm to thereby provide a spectral filter, wherein said semiconductor substrate wafer is a silicon wafer, and wherein said etching comprises electrochemical etching and includes connecting the substrate as an electrode, contacting the first surface of the substrate with an electrolyte, setting a current density which will influence etching erosion, and continuing etching to form said pores extending to a desired depth substantially perpendicular to said first surface. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 33)
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30. A method of making a spectral filter, said method comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, etching the substrate wafer to provide a macroporous structured layer having pores with controlled depths defined at least partially therethrough, removing at least one un-etched part of the substrate wafer, and coating the pores with at least one layer of a material substantially transparent within the pass-band of said spectral filter material and having a thickness of at least 10 nm to thereby provide a spectral filter, wherein said semiconductor substrate wafer is a silicon wafer, and wherein said silicon wafer is of <
100>
-orientation, andwherein said silicon wafer comprises an n-type doped wafer. - View Dependent Claims (31, 32)
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34. A method of making a spectral filter, said method comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, etching the substrate wafer to provide a macroporous structured layer having pores with controlled depths defined at least partially therethrough, removing at least one un-etched part of the substrate wafer, and coating the pores with at least one layer of a material substantially transparent within the pass-band of said spectral filter material and having a thickness of at least 10 nm to thereby provide a spectral filter, wherein said semiconductor substrate wafer is a silicon wafer, and wherein said silicon wafer is of <
100>
-orientation, andwherein said silicon wafer is a p-type doped wafer, and wherein the electrolyte additionally contains at least one organic additive. - View Dependent Claims (35, 36, 37, 38)
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39. A method of making a spectral filter, said method comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, etching the substrate wafer to provide a macroporous structured layer having pores with controlled depths defined at least partially therethrough, removing at least one un-etched part of the substrate wafer, and coating the pores with at least one layer of a material substantially transparent within the pass-band of said spectral filter material and having a thickness of at least 10 nm to thereby provide a spectral filter, wherein said semiconductor substrate wafer is of material chosen from the full possible range of alloys and compounds of zinc, cadmium, mercury, silicon, germanium, tin, lead, aluminum, gallium, indium, bismuth, nitrogen, oxygen, phosphorus, arsenic, antimony, sulfur, selenium and tellurium, and wherein said etching is electrochemical etching and includes connecting the substrate as an electrode, contacting the first surface of the substrate with an electrolyte, setting a current density which will influence etching erosion, and continuing etching to form said pores extending to a desired depth substantially perpendicular to said first surface. - View Dependent Claims (40)
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Specification