Method of making an interferometer-based bolometer
First Claim
1. A method for manufacturing an infrared radiation detection device comprising:
- providing top and bottom plates of silicon, each plate having upper and lower surfaces;
forming a concavity in the lower surface of said top plate and coating said lower surface, including the concavity, with a layer of material that renders said lower surface fully reflective;
roughening the lower surface of said bottom plate;
forming a first layer of silicon oxide on the upper surface of said bottom plate;
coating said first layer of silicon oxide with a layer of material having non-zero transmittance and a reflectance that is slightly less than unity;
depositing a second layer of silicon oxide on said reflecting material then patterning and etching said second layer of silicon oxide into a rectangular shape that is slightly larger than said concavity;
depositing a first layer of silicon nitride then heating said bottom plate to achieve stress relief;
depositing a layer of resistive material on said first layer of silicon nitride and then patterning and etching said resistive layer to form a resistor having two ends;
depositing, patterning, and etching a layer of conductive material to form contact pads to said resistor, one pad for each end of the resistor;
depositing a second layer of silicon nitride for protective purposes;
patterning and etching said first and second layers of silicon nitride to form a support platform for the resistor and supportive legs for said platform;
selectively removing said second layer of silicon oxide, thereby limiting thermal contact to the platform to said supportive legs;
forming support spacers on the upper surface of said bottom plate;
aligning the center of the concavity with the center of the platform and then attaching the lower surface of the top plate to the support spacers thereby forming an enclosure for said concavity and platform; and
evacuating said enclosure and then sealing it under vacuum.
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Accused Products
Abstract
An infrared detector device is described. It is based on an infrared analog of the Fabry Perot interferometer, using one curved, fully reflecting, plate and one planar, mainly reflecting, but partially transmitting, plate. The space between these plates behaves as a resonant cavity which can be built to respond to either a broad or a narrow band of wavelengths in the general range between 1 and 15 microns. It is also possible to combine several detectors of different narrow bands in a single device. Actual detection of the radiation is based on use of thin film resistors, having a high thermal coefficient of resistance, that are thermally isolated from the other parts of the structure. Details relating to the manufacture of the devices are given.
43 Citations
13 Claims
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1. A method for manufacturing an infrared radiation detection device comprising:
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providing top and bottom plates of silicon, each plate having upper and lower surfaces; forming a concavity in the lower surface of said top plate and coating said lower surface, including the concavity, with a layer of material that renders said lower surface fully reflective; roughening the lower surface of said bottom plate; forming a first layer of silicon oxide on the upper surface of said bottom plate; coating said first layer of silicon oxide with a layer of material having non-zero transmittance and a reflectance that is slightly less than unity; depositing a second layer of silicon oxide on said reflecting material then patterning and etching said second layer of silicon oxide into a rectangular shape that is slightly larger than said concavity; depositing a first layer of silicon nitride then heating said bottom plate to achieve stress relief; depositing a layer of resistive material on said first layer of silicon nitride and then patterning and etching said resistive layer to form a resistor having two ends; depositing, patterning, and etching a layer of conductive material to form contact pads to said resistor, one pad for each end of the resistor; depositing a second layer of silicon nitride for protective purposes; patterning and etching said first and second layers of silicon nitride to form a support platform for the resistor and supportive legs for said platform; selectively removing said second layer of silicon oxide, thereby limiting thermal contact to the platform to said supportive legs; forming support spacers on the upper surface of said bottom plate; aligning the center of the concavity with the center of the platform and then attaching the lower surface of the top plate to the support spacers thereby forming an enclosure for said concavity and platform; and evacuating said enclosure and then sealing it under vacuum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification