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EP0061803A2
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Infra-red radiation imaging devices and methods for their manufacture
Assignee: BAE Systems Electronics Ltd
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Filing: 1982-03-11
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Granted: —
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Expires: 2002-03-11
Abstract
Abstract An array of photovoltaic infra-red radiation detector elements (10) are formed in a body (11), e.g. of cadmium mercury telluride. The body (11) is present on a circuit substrate (1) which may comprise e.g. a silicon CCD for processing signals from the detector elements (10). An array of regions (13) which form the p-n junctions (12) of each detector element (10) with an adjacent body part (14) extend through the thickness of the body (11) at side-walls of an array of apertures (20) each of which is associated with a detector element (10) and is preferably formed by ion etching. These regions (13) are electrically connected to substrate conductors (2, 3) in a simple and reliable manner by a metallization layer (23) in the apertures (20) without rendering a significant area of the detector non-sensitive to radiation imaged onto the upper surface of the body (11). At least the back surface of the detector body (11) has a passivating layer (17) at least over the area around and between the apertures (20) to enhance detector element performance, and this back surface is secured to the circuit substrate (1) by a layer (21) of electrically insulating adhesive. The main body part (14) is connected to a substrate conductor (4) by metallization (24) at a surface portion which is outside of the area of the back surface between the apertures (20). Using such a securement, ion-etching and connection technique, a closely-packed array of high performance detector elements (10) can be obtained on the circuit substrate (1) with a spacing of 100 micrometres or less between adjacent apertures (20).
Inventors
- 👤 Ian Martin Baker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 06:58
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/10; H10F39/12; H10F39/15; H10F39/153; H10F39/1538; H10F39/157; H10F39/1575
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
272 words
An infra-red radiation imaging device comprising infra-red radiation detector elements formed in a body of infra-red radiation sensitive material, and a substrate having a major surface on which the body is mounted and comprising circuit elements for processing signals derived from the detector elements, each detector element comprising a region of one conductivity type which forms with an adjacent part of the body a p-n junction for detecting charge-carriers generated in the material by the infra-red radiation, said regions of the one conductivity type being electrically connected to the circuit elements via a conductor pattern present at said major surface of the substrate, characterized in that the body is separated from the substrate by a layer of electrically insulating adhesive which secures one major surface of the body to the substrate, in that a plurality of apertures extends through the thickness of the body and also through the adhesive layer to reach the conductor pattern of the substrate, each of said apertures being associated with a detector element, in that said regions of said one conductivity type extend through the thickness of the body at the side-walls of the apertures and are electrically connected to the conductor pattern of the substrate by a metallization layer in the apertures, in that the part of the body of the opposite conductivity type has an electrical connection formed by metallization at a surface portion of the body which is outside of the area of said one major surface between said apertures, and in that a passivating layer is present at said one major surface of the body over the area around and between the apertures.
Claim 2
Dependent Claim
272 words
An infra-red radiation imaging device comprising infra-red radiation detector elements formed in a body of infra-red radiation sensitive material, and a substrate having a major surface on which the body is mounted and comprising circuit elements for processing signals derived from the detector elements, each detector element comprising a region of one conductivity type which forms with an adjacent part of the body a p-n junction for detecting charge-carriers generated in the material by the infra-red radiation, said regions of the one conductivity type being electrically connected to the circuit elements via a conductor pattern present at said major surface of the substrate, characterized in that the body is separated from the substrate by a layer of electrically insulating adhesive which secures one major surface of the body to the substrate, in that a plurality of apertures extends through the thickness of the body and also through the adhesive layer to reach the conductor pattern of the substrate, each of said apertures being associated with a detector element, in that said regions of said one conductivity type extend through the thickness of the body at the side-walls of the apertures and are electrically connected to the conductor pattern of the substrate by a metallization layer in the apertures, in that the part of the body of the opposite conductivity type has an electrical connection formed by metallization at a surface portion of the body which is outside of the area of said one major surface between said apertures, and in that a passivating layer is present at said one major surface of the body over the area around and between the apertures.
Claim 3
Dependent Claim
39 words
An imaging device as claimed in Claim 1, further characterized in that the whole of said p-.n junction for detecting the radiation-generated charge-carriers is provided by the p-n junction formed by said regions at the side-walls of the apertures.
Claim 4
Dependent Claim
35 words
An imaging device as claimed in Claim 1, further characterized in that said regions of said one conductivity type each have a part which extends along the surface of the body remote from the substrate.
Claim 5
Dependent Claim
25 words
An imaging device as claimed in any of the preceding Claims, further characterized in that the body has a thickness of less than 20 micrometres.
Claim 6
Dependent Claim
48 words
An imaging device as claimed in any of the preceding Claims, further characterized in that, as measured parallel to said surface, the radiation-sensitive area of each detector element is at least ten times as large as the non-sensitive area formed by the metallization layer in the associated aperture.
Claim 7
Dependent Claim
30 words
An imaging device as claimed in any of the preceding Claims, further characterized in that the spacing between centres of adjacent apertures in the body is at most 100 micrometres.
Claim 8
Dependent Claim
25 words
An imaging device as claimed in any of the preceding Claims, further characterized in that each of said apertures is less than 30 micrometres wide.
Claim 9
Dependent Claim
31 words
An imaging device as claimed in any of the preceding Claims, further characterized in that said apertures each have a width which is less than twice the thickness of the body.
Claim 10
Dependent Claim
48 words
An imaging device as claimed in any of the preceding Claims, further characterized in that the electrical connection to said opposite conductivity part of the body is formed by metallization which extends at the periphery of the body and in contact with the outer side-walls of said body.
Claim 11
Dependent Claim
26 words
An imaging device as claimed in any of the preceding Claims, in which said body is of cadmium mercury telluride and said substrate is of silicon.
Claim 12
Independent Claim
133 words
A method of manufacturing infra-red radiation detector elements in a body of infra-red radiation sensitive cadmium mercury telluride for an imaging device as claimed in any of the preceding Claims, characterized in that the apertures associated with the detector elements are formed by localized ion-etching through the thickness of the body at least a portion of which has conductivity characteristics of g-type material at the operating temperature of the detector, and in that said ion-etching also serves to convert said g-type material adjacent the etched side-walls of the apertures into material having conductivity characteristics of n-type material at said detector operating temperature thereby forming at least a part of the regions of said one conductivity type as n-type material which extends through the thickness of the body at the side-walls of the apertures.
Claim 13
Dependent Claim
29 words
A method as claimed in Claim 11, further characterized in that said ion-etching is effected after securing said body to the substrate by the layer of electrically insulating adhesive.
Claim 14
Independent Claim
154 words
A method of manufacturing an imaging device as claimed in any of Claims 1 to 10, characterized in that, after securing the body of infra-red radiation sensitive material to the substrate by the layer of electrically insulating adhesive, one photolithographic step is used to provide on the body surface a masking layer having windows located above parts of the conductor pattern below the body, the apertures are formed using localized ion-etching through the thickness of the body at said windows, the metallization layer is provided in the apertures by depositing metal on the masking layer and on exposed parts of the conductor pattern at said apertures and then removing the masking layer to leave said metallization layer in said apertures, and another photolithographic step is used to determine the area of the surface portion of the body at which electrical connection is made to the part of the body of the opposite conductivity type.
Claim 15
Dependent Claim
17 words
An infra-red radiation imaging device manufactured by a method claimed in any of Claims 11 to 13.
References Cited (Backward Citations)
No citation records indexed.
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