GB1568958A - Methods of manufacturing infra-red sensitive devices - Google Patents
Methods of manufacturing infra-red sensitive devices Download PDFInfo
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- GB1568958A GB1568958A GB30799/75A GB3079975A GB1568958A GB 1568958 A GB1568958 A GB 1568958A GB 30799/75 A GB30799/75 A GB 30799/75A GB 3079975 A GB3079975 A GB 3079975A GB 1568958 A GB1568958 A GB 1568958A
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- infra
- anodising
- treatment
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- wafer
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- 238000000034 method Methods 0.000 title claims description 57
- 238000004519 manufacturing process Methods 0.000 title claims description 32
- 239000010410 layer Substances 0.000 claims description 102
- 238000007743 anodising Methods 0.000 claims description 61
- 239000000463 material Substances 0.000 claims description 55
- 238000011282 treatment Methods 0.000 claims description 54
- 239000002344 surface layer Substances 0.000 claims description 48
- 229910000661 Mercury cadmium telluride Inorganic materials 0.000 claims description 41
- MCMSPRNYOJJPIZ-UHFFFAOYSA-N cadmium;mercury;tellurium Chemical compound [Cd]=[Te]=[Hg] MCMSPRNYOJJPIZ-UHFFFAOYSA-N 0.000 claims description 41
- 229920002120 photoresistant polymer Polymers 0.000 claims description 23
- 238000005530 etching Methods 0.000 claims description 16
- 239000003792 electrolyte Substances 0.000 claims description 9
- 230000000873 masking effect Effects 0.000 claims description 8
- 150000004770 chalcogenides Chemical class 0.000 claims description 7
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 6
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 6
- 230000005855 radiation Effects 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 4
- 230000000717 retained effect Effects 0.000 claims description 4
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 claims description 3
- 238000003486 chemical etching Methods 0.000 claims description 3
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 3
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 3
- 239000011736 potassium bicarbonate Substances 0.000 claims description 3
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 3
- 235000011181 potassium carbonates Nutrition 0.000 claims description 3
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 3
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 3
- 235000017550 sodium carbonate Nutrition 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 2
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 claims 1
- 238000005498 polishing Methods 0.000 description 34
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical group [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 22
- 229910052737 gold Inorganic materials 0.000 description 22
- 239000010931 gold Substances 0.000 description 22
- 238000012545 processing Methods 0.000 description 12
- 229910052715 tantalum Inorganic materials 0.000 description 10
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 238000004381 surface treatment Methods 0.000 description 8
- 239000010407 anodic oxide Substances 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 206010070834 Sensitisation Diseases 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 4
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 3
- 229910052794 bromium Inorganic materials 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052793 cadmium Inorganic materials 0.000 description 2
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- WPYVAWXEWQSOGY-UHFFFAOYSA-N indium antimonide Chemical compound [Sb]#[In] WPYVAWXEWQSOGY-UHFFFAOYSA-N 0.000 description 2
- 230000003340 mental effect Effects 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000005215 recombination Methods 0.000 description 2
- 230000006798 recombination Effects 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 238000012956 testing procedure Methods 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical class C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical class [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical class [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000002800 charge carrier Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- LQBJWKCYZGMFEV-UHFFFAOYSA-N lead tin Chemical compound [Sn].[Pb] LQBJWKCYZGMFEV-UHFFFAOYSA-N 0.000 description 1
- 229910052744 lithium Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Chemical class 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000001235 sensitizing effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 229910002058 ternary alloy Inorganic materials 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000001550 time effect Effects 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
- H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
- H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
- H01L25/041—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L31/00
- H01L25/042—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L31/00 the devices being arranged next to each other
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
- H01L31/09—Devices sensitive to infrared, visible or ultraviolet radiation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/1828—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof the active layers comprising only AIIBVI compounds, e.g. CdS, ZnS, CdTe
- H01L31/1832—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof the active layers comprising only AIIBVI compounds, e.g. CdS, ZnS, CdTe comprising ternary compounds, e.g. Hg Cd Te
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Electromagnetism (AREA)
- Manufacturing & Machinery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Light Receiving Elements (AREA)
Description
(54) IMPROVEMENTS IN AND RELATING TO METHODS OF
MANUFACTURING INFRA-RED SENSITIVE DEVICES
(71) We, MULLARD LIMITED, of
Abacus House, 33 Gutter Lane, London
EC2V 8AH, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it iS to be performed, to be particularly described in and by the following statement:
This invention relates to infra-red detector devices and to methods of manufacturing infra-red detector elements for use in infra-red detector devices.
The manufacture of infra-red detector devices comprises the formation of infra-red detector elements, the mounting of the elements on suitable substrates, the application of electrical connections to the elements, the testing of the elements provided with said connections and the eventual final encapsulation of the elements and applied contacts in a suitable envelope. Infra-red detector devices in some forms comprise only a single infra-red detector element and in other forms comprise a plurality of infra-red detector elements, for example arranged as a linear array. For devices in which the operation is dependent upon the intrinsic photoconductivity of the infra-red sensitive material the manufacture of the elements comprises steps such as material preparation, element definition by a combination of etching and polishing techniques, surface treatments and application of contact layers.
Hitherto in the manufacture of the elements it has been necessary in order to enhance the detectivity D * of the element to perform a treatment on the surface of the sensitive area of the element which has the effect of lowering the surface recombination velocity. In general for the materials commonly employed in infra-red detector elements this surface treatment has been effected by a controlled etching process.
However even when carrying out such an etching process for the sensitisation of the element it has been found for some materials that the detectivity D * of the element is considerably degraded if the element should at some stage either in manufacture or in eventual use or stage be subjected to an elevated temperature. In particular it is found that with an element of cadmium mercury telluride the detectivity is degraded if the element is subjected to a temperature above 70"C.
According to a first aspect of the invention an infra-red detector device comprises at least one element of infra-red sensitive material formed of a ternary intermetallic chalcogenide, wherein at least at one side of the element provided for receiving incident radiation a surface layer produced by electrolytic anodising of the element material is present.
The element material may be of cadmium mercury telluride (Cdl.xHgxTe, where 0 < x < 1) in which the atomic ratio of cadmium to mercury has been chosen to produce a desired infra-red sensitivity with an appropriate cut-off wavelength, for example a cutoff wavelength in the region of 12 microns when the device is for use in the 8 - 12 micron window, or a cut-off wavelength in the region of 4 to 5 microns when the device is for use in the 3 - 5 micron window.
The use in a device comprising a cadmium mercury telluride element of an anodically produced surface layer is found to aid the obtainment of a high detectivity. Furthermore said surface layer also is found to have a protective or passivating effect at least in so far as it has been found that the device can be subjected to elevated temperatures without severe degradation in the detectivity, for example a high detectivity of a cadmium mercury telluride element may be obtained and maintained even after subjecting the element to a temperature of 90"C. The reasons for the obtainment of the high detectivity are not clear but it has been found that when applying the anodic surface treatment to a material such as cadmium mercury telluride there is formed a very hard oxide layer at the surface. However it is a matter of some surprise that a surface layer produced by electrolytic anodising of a ternary alloy such as cadmium mercury telluride yields the said enhanced properties because previous attempts to apply such material treatments to an infra-red sensitive material of the binary
III-V compound indium antimonide have resulted in certain instabilities in the detector device, particularly when the device has been subjected to short wavelength radiation. This has hitherto been attributed to trapping effects in the anodically produced layer at the surface of the indium antimonide body. It can be postulated that on account of the enhanced detectivity properties obtained with cadmium mercury telluride elements such trapping effects are absent or occur to a considerably lesser degree in the anodically produced surface layer but it is emphasised that the precise physical composition of the surface layer has not been determined and reasons for the enhanced detectivity and stability properties cannot readily be formulated.
The infra-red detector element having the anodically produced surface layer may be provided in various forms. In some forms the element is substantially wafer-shaped having at one major side of the body at least one active surface area defined between a pair of oppositely located ohmic contact layers, the anodically produced surface layer being present over at least part of the or each active surface area. In such a device in which the operation is dependent upon the intrinsic photoconductivity of the infra-red sensitive material the provision of an anodically produced surface layer at the or each active surface area is found to aid the obtainment of a high detectivity and to provide good protection for maintaining said high detectivity.
Within the scope of the invention, in addition to devices in which the operation is based on the intrinsic photoconductivity of infra-red sensitive material there are also devices in which the operation is based on a photo-voltaic effect, the latter devices comprising at least one element of the said infrared sensitive material having ap-n junction, at least part of the element surface via which the incident radiation passes to the detecting p-n junction for the generation of free charge carriers comprising a surface layer produced by electrolytic anodising of the element material. Thus within the scope of the invention are photo-voltaic infra-red detectors in which the or each element is of cadmium mercury telluride and an anodically produced surface layer is present at the side of the element provided for receiving incident radiation.
In one of the said wafer-shaped forms with the active surface area defined between the contact layers the element is of substantially rectangular outline and comprises a single active surface area at the one major side, the active surface area and the oimic contacts extending across the body surface in one direction at the one major side, the anodically produced surface layer occupying the whole active surface area and further extending on the side surfaces of the body adjoining the active surface area.
In said wafer-shaped forms with the active surface area defined between the contact layers it is found that further enhanced protection and stability is obtained when at the opposite major side of the body there is also a surface layer produced by the electrolytic anodising of the element material.
According to a second aspect of the invention there is provided a method of manufacturing an infra-red detector element, wherein as a step in the manufacture at least part of the surface of a body of infra-red sensitive material formed of a ternary intermetallic chalcogenide is subjected to an electrolytic anodising treatment.
This method may be advantageously employed when the infra-red sensitive material is of cadmium mercury telluride (CdxHg 1-xTe, when 0 < x < 1).
When the infra-red sensitive material is of cadmium mercury telluride and the anodising treatment is effected in such manner that the body of cadmium mercury telluride is totally immersed in the electrolyte and a conductive connection to the body, or at least to a metal surface later on a supporting body, may be made in the electrolyte via another body of cadmium mercury telluride.
For the anodising of cadmium mercury telluride the acidic solutions commonly used in anodising processes are not entirely suitable due to the fact that they are found to redissolve the anodically produced surface layer. It has been found that various salts of sodium, potassium and lithium may be advantageously employed as the electrolyte, for example sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.
In a method in accordance with the invention for the treatment of a cadmium mercury telluride body the anodising treatment may be effected for a period as to produce a surface layer of at least 100 A thickness, for example a layer having a thickness of approximately 500 A.
It has been found that for some materials it is advantageous to subject the element after the anodising treatment to a treatment at elevated temperature, for example in the case of some cadmium mercury telluride elements, subjecting the elements to a baking treatment at a temperature in the range of 60"C to 70"C for an extended period may be desirable.
In a method in accordance with the second aspect of the invention the surface layer produced by the electrolytic anodising may be at least in part retained in the further manufacturing steps and therefore result in an element suitable for use in a detector device in accordance with the invention. However within the scope of the method in accordance with the second aspect of the invention there is also the case where the surface layer produced by electrolytic anodising in the said step is only temporarily retained and is removed at a later stage in the manufacture.
For example the said surface layer may be replaced at least in part by a further passivating layer at a later stage in the manufacture.
In one form of the method in accordance with the second aspect of the invention, immediately prior to the electrolytic anodising treatment at least said part of the surface of the body is subjected to an etching treatment. This etching treatment is normally carried out for sensitisation purposes in order to lower the surface recombination velocity when the said part of the surface includes one or more active surface areas of one or more elements to be formed in the body. However within the scope of the method in accordance with the second aspect of the invention there is also the case where for treatment of the surface either at the active surface area and/or a another part of the body the anodic treatment may not necessarily be immediately preceded by an etching treatment for sensitisation purposes.
The electrolytic anodising treatment may be effected in the presence of a masking layer on the body of infra-red sensitive material, for example a masking layer of photoresist.
In one form of the method the manufacture comprises forming simultaneously in a single wafer-shaped body of infra-red sensitive material a plurality of elemental body portions each comprising at one major side an active surface area defined between a pair of applied ohmic contact layers, at least the surface parts of the wafer-shaped body comprising the active surface areas of the elemental body portions being subjected to the electrolytic anodising treatment.
In such a form the wafer-shaped body may be adhered to a supporting body and the elemental body portions are defined in the wafer-shaped body while present on the supporting body by a process including a chemical etching material-removal treatment, the anodising treatment being thereafter effected on the elemental body portions present on the supporting body and prior to the application of the contact layers. This form has the advantage that if etching were to be employed for element definition after the anodising treatment then for some materials, for example cadmium mercury telluride, the problem arises that the anodised surface layer is etched considerably faster than the element material thus rendering impractical the use of a chemical etching process for such element definition after anodising. Of course, it may nevertheless, if desired, be possible to use other methods of material removal, for example sawing, sandblasting or sputter etching, subsequent to an anodising treatment. However a further advantage resides in that by effecting the anodising treatment after the definition of the elemental body portions the side surfaces of the elemental body portions adjoining the active surface areas can additionally be subjected to the anodising treatment. Furthermore it is desirable to effect the anodising treatment before application of the contact layers because due to the high resistivity of the anodic layer initially formed at the surface of the infra-red sensitive material the anodising current will be taken preferentially by the metal contact layers and thus the desired anodising of the infra-red sensitive material will not proceed beyond an initial covering and also the metal contact layers may be eroded possibly even to the point of their removal.
In one particular form of the last described method, the supporting body, for example of ceramic material, comprises an electrically conductive surface layer of a material, for example tungsten or tantalum, which can remain substantially unaffected by the anodising treatment at least in so far as it will not be attacked at a greater rate than the infra-red sensitive material, and after the said definition of the elemental body portions each elemental body portion remains adhered to the supporting body in such manner that it is substantially electrically isolated from the underlying electrically conductive surface layer present at the surface of the supporting body, a plurality of conductive layer interconnections thereafter being provided between the upper surfaces of the elemental body portions and exposed parts of said electrically conductive surface layer which for the subsequently effected anodising treatment is employed as part of a common supply conductor to the elemental body portions. In this form the anodising of parts of the surfaces of the elemental body portions comprising the active surface areas may be readily effected, said parts being defined for example by masking layer portions of photoresist on the elemental body portions.
For a full description of the various advantages in preparing and handling a plurality of elemental body portions, including the subsequent application of contact layers thereon, reference is invited to our copending Patent Application No. 30800/75 (Serial No. 1559473) (PHB 32508).
Prior to adhering the wafer-shaped body to the supporting body, at least the surface of the wafer-shaped body which is to be adhered to the supporting body may be subjected to an electrolytic anodising treatment.
In this manner the surfaces of the elemental body portions opposite the active surface areas will be provided with an anodically produced surface layer. This as already mentioned is found to further enhance the detectivity D * and the stability.
An embodiment of the invention will now be described, by way of example, with reference to the diagrammatic drawings accompanying the Provisional Specification, in which:
Figure 1 is a cross-sectional view of a wafer of cadmium mercury telluride mounted on a polishing block and at a stage in the manufacture after effecting a surface treatment;
Figure 2 shows in cross-section the wafer after mounting on a further polishing block;
Figure 3 shows in cross-section the residual wafer on the further polishing block after a thickness reduction step;
Figures 4 and 5 show in plan view and cross-section respectively the wafer on the further polishing block after a further step in the processing, Figure 5 being a section on the line V-V in Figure 4;
Figure 6 shows in cross-section the wafer on the further polishing block after a further thickness reduction step;
Figure 7 shows in plan view a portion of the wafer after a further step in the processing, and
Figures 8 and 9 are cross-sectional views taken along the line VIII-VIII and IX-IX respectively of Figure 7;
Figures 10 to 12 show in cross-section part of the wafer at further stages of the processing;
Figures 13 and 14 show in cross-section and plan view respectively the same part of the wafer at a further stage in the processing after effecting an anodic surface treatment,
Figure 14 being a cross-section along the line
XIV-XIV in Figure 13;
Figures 15 and 16 show in cross-section the same part of the wafer at further stages in the processing;
Figures 17 and 18 show in cross-section and plan view respectively the same part of the wafer at a stage in the processing after individual elemental body portions of the wafer have been provided with contact layers, Figure 17 being a cross-section along the line XVII-XVII in Figure 18;
Figure 19 is an enlarged plan view of one elemental body portion with applied contact layers as present on the polishing block, and
Figures 20 and 21 are cross-sectional views taken along the line XX-XX and XXI-XXI respectively of Figure 19.
The Figures in the drawings accompanying the Provisional Specification are not to scale and consequently the relative dimensional proportions are totally distorted, particularly in a practical embodiment the thickness of the various layers in relation to their lateral extent will be much smaller thar may otherwise be apparent from the drawings.
The embodiment now te be described comprises the manufacture of a large plurality of, in the region of two thousand, infrared detector elements of cadmium mercury telluride. In this embodiment the material composition, that is the atomic ratio of cadmium to mercury, is such as to produce a cut-off wavelength in the region of 12 microns in order that the elements may be used in infra-red detectors suitable for use in the 8 - 12 micron window.
The starting material is a disc-shaped wafer of the cadmium mercury telluride of approximately 10 mm diameter and 0.5 mm thickness.
The wafer 1 is mounted on a ceramic polishing block 2 with a layer of wax 3. The polishing block has raised shoulders of 200 microns height. Polishing of the surface of the wafer projecting beyond the shoulders is effected by a rotary machine using a base lap and an abrasive slurry. The polishing is a multi-stage process with progressively less damage being produced in the crystal structure as the thickness is reduced to the desired value of 200 microns. This progressive reduction in damage is achieved by the use of progressively finer abrasive particles and base laps. This polishing is continued until the surface of the wafer lies flush with the surfaces of the shoulders of the polishing block 2. To remove the remainder of the surface damage an etching treatment is effected with an etchant comprising bromine in methanol.
An anodic surface treatment is then effected with the wafer 1 still remaining adhered to the polishing block 2 so that treatment is effected on the exposed upper and side surfaces. This is effected in this example in a solution of sodium bicarbonate by connecting the positive electrode a D.C.
supply of 30 volts to the wafer using another piece of cadmium mercury telluride in the solution to form the contact to the wafer 1 and using a cathode of gold connected to the negative electrode of the supply. The current, which initially is approximately 150 milliamps, is allowed to pass for approximately 30 seconds, a constant voltage being maintained across the electrodes during this period. As a confirmation of the formation of an anodic oxide layer on the exposed surfaces of the wafer and having the desired thickness observation is made of the colour of the surface which in the present example should be a deep blue. Figure 1 shows the wafer 1 of 200 microns thickness having an anodically produced surface layer 4.
The wafer 1 is now removed from the polishing block 2 and is adhered via the anodised major surface to a further polishing block 5 of high density alumina. The supporting body formed by the polishing block 5 has outer shoulders of 25 microns in height and within the shoulders the surface has a layer 6 of tantalum thereon. The wafer 1 is adhered to the tantalum layer 6 with a layer of wax 7.
Although the previously formed anodic oxide surface layer 4 is shown in Figure 2 in the following Figures it is omitted for the sake of convenience of illustration. A multistage polishing operation is effected with a rotary lapping machine using an alumina slurry, the particle size and base laps being chosen such that the damage produced is progressively reduced in successive stages.
This polishing is effected until the polished surface of the wafer 1 is substantially coplanar with the raised shoulders of the polishing block 5. Figure 3 shows the wafer 1 after this thickness reduction step, the wafer 1 now having a thickness of approximately 25 microns.
With the wafer 1 of reduced thickness still adhered via the wax layer 7 to the tantalum layer 6 on the polishing block 5 a layer of photoresist is applied on the upper surface of the wafer 1. A photomasking and developing process is then effected to define a plurality of substantially parallel strip-shaped openings in the photoresist layer. An etching treatment is then effected using a suitable etchant for cadmium mercury telluride to form in the wafer a first plurality of substantially parallel extending channels 8 which define on the polishing block a plurality of substantially parallel extending strip portions 9 of cadmium mercury telluride. Figures 4 and 5 show the channels 8 and the strips 9. In this example the channels 8 are of
approximately 50 microns in width and the stnps are all of approximately 200 microns in width.
The next stage in the processing is the removal of the parts of the photoresist layer remaining on the strip portions 9. Thereafter a thickness reduction is effected in order to reduce the thickness of the strip portions 9 to approximately 8 microns and at the same time effect a curvature of the exposed upper longitudinal edges of the strip portions 9.
This is effected by first polishing with a lapping machine using a fine grade pad and a fine abrasive until the residual thickness of the strip portions 9 is approximately 12 microns and thereafter etching the strip portions 9 to remove material of a thickness in the region of 4 to 5 microns. The etchant used comprises bromine and methanol. In this manner the upper longitudinal edges of the
strip portions are rounded and this effect is utilised in order to enable the external contacting of the elements when finally produced. Furthermore the etching is found to have a sensitising effect which yields an enhanced detector performance. Figure 6 shows in cross-section the strip portions 9 after the etching process. Due to the distortion of the relative dimensions in the drawing the rounding of the longitudinal edges does not appear to be significant but in practice it is found that the curvature extends in the cross-section over a distance of at least 15 microns from the bottom surface at each longitudinal edge. It is also noted that during the polishing to effect the said reduction in thickness from 12 microns to 7 to 8 microns the exposed wax layer parts in the channels 8 are removed. Thus in the section of Figure 6 the wax layer 7 is now present only below each strip portion 9.
The next stage in the processing is the application of a layer of photoresist on the upper surfaces of the strip portions. Using a conventional photomasking and developing process a plurality of substantially parallel extending strips situated normal to the strip portions 9 are removed from the photoresist layer and etching of the exposed material of the strip portions 9 is effected using a suitable etchant for cadmium mercury telluride to obtain a plurality of substantially parallel extending channels 10 in the wafer material of the strip portions to define on the polish- ing block an array of substantially rectangular elemental body portions 11 of cadmium mercury telluride. Figure 7 is a plan view of part of the wafer after forming the channels 10 and thus defining the elemental body portions 11, the remaining parts of the photoresist layer used for the masking having been removed. Figures 8 and 9 are cross-sections along the lines VIII-VIII and IX-IX respectively of Figure 7. Figure 8 shows the rounding of the edges of the elemental body portions 11 on two opposite sides in contrast to the near vertical edges (Figure 9) on the other two sides of the elemental body portions. In this example the width of the channels 10 as finally etched is approximately 30 microns and the final surface area of the elemental body portions 11 as shown in Figure 7 is 200 microns x 50 microns.
The next step in the processing is the application of a further layer 12 of photoresist to the surface of the elemental body portions 11 and the exposed surface portions of the wax layer 7 and the tantalum layer 6 on the polishing block 5. By a photomasking and developing step the photoresist layer 12 is defined so that openings 13 (Figure 10) are formed therein, said openings being in the form of strips of approximately 50 microns width extending parallel to the channels 8 and exposing the elemental body portions 11 at one end thereof at which a rounded edge is present and also exposing the adjoining part of the tantalum layer 6 on the polishing block 5 from which part the wax layer 7 was previously removed in the thickness reduction polishing step. Figure 10 is a cross-section, corresponding to the section of Figure 8, showing the photoresist layer 12 and the openings 13 therein.
A layer of gold of 0.5 micron thickness is now applied by sputtering. The gold is thus deposited on the photoresist layer 12 and in the openings 13. The photoresist layer 12 is then dissolved in a suitable solvent and the deposited gold thereon is thereby removed by a lift-off technique. Figure 11 shows a section, corresponding to the section of Figure 10, with gold layer strips 14 of approximately 50 microns width forming contact between the upper surfaces of the elemental body portions 11 and the tantalum layer 6 on the polishing block 5. The gold layer portions 14 are required to establish this electrical connection for a subsequent process because due to the combination of the anodic oxide layer previously provided and located at the lower surfaces of the elemental body portions and the separation of the said body portions from the tantalum layer 6 by the wax layer 7 the elemental body portions 11 would otherwise all be effectively isolated.
A further layer 15 of photoresist is applied on the upper surface of the assembly and by a photomasking and developing step apertures 16 in the form of rectangular strips of approximately 80 microns width are formed in the photoresist layer 15. Figure 12 is a crosssection, corresponding to the section of Figure 11, showing the strip apertures 16 which are located centrally on the surfaces of the elemental body portions 11. These strip apertures 16 have a width in the direction of the larger cross dimensions of the elemental body portions, that is in the direction of the section of Figure 11 which is slightly larger than the desired final dimension of the active surface areas of the elemental body portions.
In the presence of the defined photoresist layer 15 the exposed surface portions are subjected to a sensitisation treatment by etching in bromine and ethylene glycol to remove material over at most 1 micron thickness. There is then effected an anodic surface treatment in a solution of sodium bicarbonate. The connection of the elemental body portions 11 to the positive terminal of the supply is via the gold layer portions 14, the tantalum layer 6 and a further connection in the solution to the tantalum layer 6 provided in this example by another body of cadmium mercury telluride or a tungsten wire. Anodising is effected, using a cathode of gold in the solution, with a constant applied voltage of 30 volts at an initial current of approximately 150 milliamps for a period of a few minutes. This anodic treatment produces a surface layer which is found to consist mainly of an oxide of the elemental constituents. Figure 12 diagrammatically shows in broken outline the anodic oxide layer 17 produced at the exposed surfaces of the elemental body portions 11.
The residual parts of the photoresist layer 15 are now dissolved and Figures 13 and 14 respectively show in plan view and section the assembly thus formed with the gold layer strips 14 still present and the elemental body portions 11 having surface parts provided with an anodic oxide layer 17. The gold strips 14 are shown shaded in the plan view of
Figure 13 for clarity of illustration. It is to be noted that as the photoresist layer was removed from parts of the channels 10 between the elemental body portions 11 along the strip apertures 16 parts of the longitudinal side surfaces of the elemental body porti
sputtering and Figure 16 is a section, corres ;ponding to the section of Figure 15, showing
the gold layer 20 covering the surface of the
photoresist layer part 18 and the exposed
surface parts of the elemental body portions
11. It is noted that due to the removal of the
anodised surface layer along the strip por
tions 19 (Figure 15) by a polishing process
the gold layer 20 contacts the surfaces of the
elemental body portions 11 at no location
where there is present any such anodised
layer part, that is to say the edges of the gold
contact layer 20 are in true registration with
the edges of the residual part of the anodised
surface layer.
Following the deposition of the gold layer
20 the remaining portions of the photoresist
layer 18 are dissolved and the portions of the
gold layer 20 thereon are thus removed by a lift-off effect. This leaves on each elemental
body portion 11 a pair of gold contact layers
21 and 22 defining therebetween an active
surface area of 50 microns x 50 microns. The
contact layers 21 extend over the rounded
edge at one side of the elements and the
contact layers 22 extend in part on the
residual portions of the gold strips 14 cover
ing the rounded edge at the other side of the
elements. Thus a certain asymmetry occurs
in so far as the contact layers 22 are in part
thicker on one side than the contact layers 21
on the other side.
Figures 17 and 18 show in cross-section
and plan view respectively part of the assem
bly after dissolving the photoresist layer por
tions 18. The previously effected rounding of
the opposite edges of the elemental body
portions over which the contact layers 21 and
22 are provided enables the elemental body
portions 11 with said applied contact layers
to be employed in the further manufacture of
an infra-red detector device in such manner
that external electrical contact to the element
tal body portions is readily facilitated by a
film deposition process. In this respect refer
ence is invited to our co-pending Patent
Application No. 30806/75 (Serial No.
1559474) (PHB 32509).
At the stage of the processing as shown by
Figures 17 and 18 there is present a large
plurality, in the region of approximately two
thousand cadmium mercury telluride ele
mental body portions 11 with applied contact
layers all remaining adhered to the polishing
block 5 via the wax layer 7. It will be appreci
ated that due to the manner of processing,
that is starting from a slice cut from an ingot,
there may exist some degree of variation in
the characteristics of the elemental body por
tions 11 throughout the whole array as
formed. In order to be able to use the ele
mental body portions 11 effectively without
appreciable wastage the next step in the pro
cessing is to remove individual elemental
body portions 11 from selected positions of the array and subject the elements thus removed to various testing procedures as previously described. In this way a form of 'map' of the elemental characteristics over the whole array can be obtained and this used when selecting one or more of the elemental body portions 11 for removal in the further manufacture of an infra-red detector device.
In particular in the manufacture of a multielement device then a group of adjacently situated elemental body portions in the array on the polishing block will be selected for removal in accordance with the evaluated characteristics of the individual elemental body portions previously removed for the testing procedures.
In the present embodiment the elemental body portions 11 are individually removed from the polishing block mechanically by lifting from the wax with the aid of a fine tool.
Figure 19 shows in an enlarged plan view one elemental body portion 11 when still adhered to the polishing block 5 via the wax layer 7 and Figures 20 and 21 are crosssections taken along the line XX-XX and
XXI-XXI respectively of Figure 19. In Figures 20 and 21 the anodic oxide layer produced before mounting the wafer on the polishing block 5 is indicated by the broken line 4. The anodic oxide layer produced after the sensitisation of the active surface layer after the element definition is indicated by the broken line 17 and from Figure 21 it is seen that this very thin surface layer is also formed along the adjoining parts of the longitudinal side faces of the elemental body portion 11.
The lateral boundaries of the area of the upper surface over which the anodic surface treatment was carried out are shown by the chain lines 24 in Figure 19.
From Figure 20 it is seen that the gold contact layer of 0.5 micron thickness extends over the rounded edge of the elemental body portion 11 on one side thereof. On the rounded edge at the opposite side of the elemental body portion 11 the residual portion of the gold strip 14 of 0.5 micron thickness is present. On this portion of the strip 14 the gold contact layer 22 of 0.5 micron thickness is present, the contact layer 22 further extending in contact with the upper surface of the elemental body portion 11. Thus on one side of the elemental body portion the composite gold contact layer 14, 22 has a thickness of 1 micron whereas on the other side the gold contact layer has a substantially uniform thickness of 0.5 micron.
It will be appreciated that many modifications are possible within the scope of the invention. For example the anodising method may be applied in the manufacture of infra-red detectors in which the infra-red sensitive material is a ternary intermetallic chalcogenide other than cadmium mercury telluride. One such material is lead tin tel luride (Pbl-xSnxTe, where 0 < x < 1).
Although in the embodiment described the method comprises the anodising of active surface areas of elemental body portions of cadmium mercury telluride having a uniform material composition and for use in detectors of which the operation is based on the intrinsic photoconductivity, within the scope of the invention there are also infra-red detector devices comprising at least one element of cadmium mercury telluride having a p-n junction formed therein and constructed for operation as photo-voltaic detectors at least a surface part of the element having a surface layer produced by electrolytic anodising of the element material. Furthermore also within the scope of the invention are methods of manufacturing elements for such detectors in which as a step in the manufacture at least part of the surface of a body of cadmium mercury telluride is subjected to an electrolytic anodising treatment.
WHAT WE CLAIM IS:
1. An infra-red detector device comprising at least one element of infra-red sensitive material formed of a ternary intermetallic chalcogenide said element comprising at least at one side provided for receiving incident radiation a surface layer produced by electrolytic anodising of the element material.
2. An infra-red detector device as claimed in Claim 1, wherein the element material is of cadmium mercury telluride (Cdl-xHgxTe, where 0 < x < 1).
3. An infra-red detector device as claimed in Claim 1 or Claim 2, wherein the element is in the form of a substantially wafer-shaped body having at one major side of the body at least one active surface area defined between a pair of oppositely located ohmic contact layers, the anodically produced surface layer being present over at least part of the or each active surface area.
4. An infra-red detector device as claimed in Claim 3, wherein the element is of substantially rectangular outline and comprises a single active surface area at the one major side, the active surface area and the ohmic contacts extending across the body surface in one direction at the one major side, the anodically produced surface layer occupying the whole active surface area and further extending on the side surfaces of the body adjoining the active surface area.
5. An infra-red detector device as claimed in Claim 3 or Claim 4, wherein at the opposite major side of the body there is also a surface layer produced by the electrolytic anodising of the element material.
6. An infra-red detector device substantially as herein described with reference to
Figures 19 to 21 of the drawings accompanying the Provisional Specification.
7. A method of manufacturing an infrared detector element, wherein at a step in the manufacture at least part of the surface of a body of infra-red sensitive material formed of a ternary intermetallic chalcogenide is subjected to an electrolytic anodising treatment.
8. A method as claimed in Claim 7, wherein the infra-red sensitive material is of cadmium mercury telluride (CdxHgl-xTe, where 0 < x < 1).
9. A method as claimed in claim 8, wherein for the anodising treatment the body of cadmium mercury telluride is totally immersed in the electrolyte and a conductive connection to the body is made in the electrolyte via another body of cadmium mercury telluride.
10. A method as claimed in Claim 8 or
Claim 9, wherein the electrolyte is selected from the group consisting of sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.
11. A method as claimed in any of
Claims 8 to 10, wherein the anodising treatment is effected for such a period as to produce a surface layer of at least 100 A thickness.
12. A method as claimed in any of
Claims 7 to 11, wherein after the anodising treatment the body is subjected to a baking treatment.
13. A method as claimed in any of
Claims 7 to 12, wherein the surface layer produced by the electrolytic anodising is subsequently removed and replaced by a further layer of passivating material.
14. A method as claimed in any of
Claims 7 to 12, wherein the surface layer produced by the electrolytic anodising is at least in part retained in the further manufacturing steps.
15. A method as claimed in any of
Claims 7 to 14, wherein immediately prior to the electrolytic anodising at least said part of the surface of the body is subjected to an etching treatment,
16. A method as claimed in any of
Claims 7 to 15, wherein the electrolytic anodising treatment is effected in the presence of a masking layer.
17. A method as claimed in Claim 16, wherein the masking layer is of a photoresist.
18. A method as claimed in any of
Claims 7 to 17, wherein the manufacture comprises forming simultaneously in a single wafer-shaped body of infra-red sensitive material a plurality of elemental body portions each comprising at one major side an active surface area defined between a pair of applied ohmic contact layers, at least the surface parts of the wafer-shaped body comprising the active surface areas of the elemental body portions being subjected to the electrolytic anodising treatment.
19. A method as claimed in Claim 18,
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (22)
1. An infra-red detector device comprising at least one element of infra-red sensitive material formed of a ternary intermetallic chalcogenide said element comprising at least at one side provided for receiving incident radiation a surface layer produced by electrolytic anodising of the element material.
2. An infra-red detector device as claimed in Claim 1, wherein the element material is of cadmium mercury telluride (Cdl-xHgxTe, where 0 < x < 1).
3. An infra-red detector device as claimed in Claim 1 or Claim 2, wherein the element is in the form of a substantially wafer-shaped body having at one major side of the body at least one active surface area defined between a pair of oppositely located ohmic contact layers, the anodically produced surface layer being present over at least part of the or each active surface area.
4. An infra-red detector device as claimed in Claim 3, wherein the element is of substantially rectangular outline and comprises a single active surface area at the one major side, the active surface area and the ohmic contacts extending across the body surface in one direction at the one major side, the anodically produced surface layer occupying the whole active surface area and further extending on the side surfaces of the body adjoining the active surface area.
5. An infra-red detector device as claimed in Claim 3 or Claim 4, wherein at the opposite major side of the body there is also a surface layer produced by the electrolytic anodising of the element material.
6. An infra-red detector device substantially as herein described with reference to
Figures 19 to 21 of the drawings accompanying the Provisional Specification.
7. A method of manufacturing an infrared detector element, wherein at a step in the manufacture at least part of the surface of a body of infra-red sensitive material formed of a ternary intermetallic chalcogenide is subjected to an electrolytic anodising treatment.
8. A method as claimed in Claim 7, wherein the infra-red sensitive material is of cadmium mercury telluride (CdxHgl-xTe, where 0 < x < 1).
9. A method as claimed in claim 8, wherein for the anodising treatment the body of cadmium mercury telluride is totally immersed in the electrolyte and a conductive connection to the body is made in the electrolyte via another body of cadmium mercury telluride.
10. A method as claimed in Claim 8 or
Claim 9, wherein the electrolyte is selected from the group consisting of sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.
11. A method as claimed in any of
Claims 8 to 10, wherein the anodising treatment is effected for such a period as to produce a surface layer of at least 100 A thickness.
12. A method as claimed in any of
Claims 7 to 11, wherein after the anodising treatment the body is subjected to a baking treatment.
13. A method as claimed in any of
Claims 7 to 12, wherein the surface layer produced by the electrolytic anodising is subsequently removed and replaced by a further layer of passivating material.
14. A method as claimed in any of
Claims 7 to 12, wherein the surface layer produced by the electrolytic anodising is at least in part retained in the further manufacturing steps.
15. A method as claimed in any of
Claims 7 to 14, wherein immediately prior to the electrolytic anodising at least said part of the surface of the body is subjected to an etching treatment,
16. A method as claimed in any of
Claims 7 to 15, wherein the electrolytic anodising treatment is effected in the presence of a masking layer.
17. A method as claimed in Claim 16, wherein the masking layer is of a photoresist.
18. A method as claimed in any of
Claims 7 to 17, wherein the manufacture comprises forming simultaneously in a single wafer-shaped body of infra-red sensitive material a plurality of elemental body portions each comprising at one major side an active surface area defined between a pair of applied ohmic contact layers, at least the surface parts of the wafer-shaped body comprising the active surface areas of the elemental body portions being subjected to the electrolytic anodising treatment.
19. A method as claimed in Claim 18,
wherein the wafer-shaped body is adhered to a supporting body and the elemental body portions are defined in the wafer-shaped body while present on the supporting body by a process including a chemical etching material-removal treatment the anodising treatment being thereafter effected on the elemental body portions present on the supporting body and prior to the application of the contact layers.
20. A method as claimed in Claim 19, wherein after said definition of the elemental body portions each elemental body portion remains adhered to the supporting body in such manner that it is substantially electrically isolated from an underlying electrically conductive surface layer present at the surface of the supporting body, a plurality of conductive layer interconnections thereafter being provided between the upper surfaces of the elemental body portions and exposed parts of said electrically conductive surface layer which for the subsequently effected anodising treatment is employed as part of a common supply conductor to the elemental body portions.
21. A method as claimed in Claim 19 or
Claim 20, wherein prior to adhering the wafer-shaped body to the supporting body, at least the surface of the wafer-shaped body which is to be adhered to the supporting body is subjected to an electrolytic anodising treatment.
22. A method of manufacturing an infra-red detector element substantially as herein described with reference to the drawings accompanying the Provisional Specification.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB30799/75A GB1568958A (en) | 1976-10-22 | 1976-10-22 | Methods of manufacturing infra-red sensitive devices |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB30799/75A GB1568958A (en) | 1976-10-22 | 1976-10-22 | Methods of manufacturing infra-red sensitive devices |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1568958A true GB1568958A (en) | 1980-06-11 |
Family
ID=10313309
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB30799/75A Expired GB1568958A (en) | 1976-10-22 | 1976-10-22 | Methods of manufacturing infra-red sensitive devices |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1568958A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4318217A (en) * | 1980-08-15 | 1982-03-09 | U.S. Philips Corporation | Method of manufacturing an infra-red detector device |
| FR2492171A1 (en) * | 1980-10-10 | 1982-04-16 | Philips Nv | Infrared radiation detector mfr. - involves diffusing mercury into mercury cadmium telluride body to form N-type layer at operating temp. |
| DE3033457A1 (en) * | 1980-09-05 | 1982-04-22 | Naamloze Vennootschap Philips' Gloeilampenfabrieken, 5621 Eindhoven | Infrared radiation detector mfr. - involves diffusing mercury into mercury cadmium telluride body to form N-type layer at operating temp. |
| FR2536908A1 (en) * | 1982-11-30 | 1984-06-01 | Telecommunications Sa | METHOD FOR MANUFACTURING A MATRIX INFRARED SENSOR WITH FRONT-SIDE LIGHTING |
| EP0139408A1 (en) * | 1983-09-28 | 1985-05-02 | The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and | Thermal Detector |
| EP0293216A2 (en) * | 1987-05-27 | 1988-11-30 | The Marconi Company Limited | Manufacture of infra-red detectors |
| US4791298A (en) * | 1986-02-14 | 1988-12-13 | U.S. Philips Corp. | Infrared detectors |
| DE3915321C1 (en) * | 1988-05-11 | 2000-12-28 | Raytheon Co | Method for forming a passivation area on a semiconductor device from a II-VI connection and application of the method |
| GB2372630A (en) * | 1988-03-29 | 2002-08-28 | Santa Barbara Res Ct | Epitaxial passivation of group 2-6 infrared photodetectors |
| EP2051303A2 (en) * | 2007-08-28 | 2009-04-22 | Biomimetics Technologies Inc. | Method to detect poor infrared rays, Microchip that is able to detect poor infrared rays and apparatus working with these microchips |
-
1976
- 1976-10-22 GB GB30799/75A patent/GB1568958A/en not_active Expired
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4318217A (en) * | 1980-08-15 | 1982-03-09 | U.S. Philips Corporation | Method of manufacturing an infra-red detector device |
| DE3033457A1 (en) * | 1980-09-05 | 1982-04-22 | Naamloze Vennootschap Philips' Gloeilampenfabrieken, 5621 Eindhoven | Infrared radiation detector mfr. - involves diffusing mercury into mercury cadmium telluride body to form N-type layer at operating temp. |
| FR2492171A1 (en) * | 1980-10-10 | 1982-04-16 | Philips Nv | Infrared radiation detector mfr. - involves diffusing mercury into mercury cadmium telluride body to form N-type layer at operating temp. |
| FR2536908A1 (en) * | 1982-11-30 | 1984-06-01 | Telecommunications Sa | METHOD FOR MANUFACTURING A MATRIX INFRARED SENSOR WITH FRONT-SIDE LIGHTING |
| EP0116791A1 (en) * | 1982-11-30 | 1984-08-29 | Societe Anonyme De Telecommunications (S.A.T.) | Method of manufacturing a matrix infra-red detector with front side illumination |
| EP0139408A1 (en) * | 1983-09-28 | 1985-05-02 | The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and | Thermal Detector |
| US4948963A (en) * | 1983-09-28 | 1990-08-14 | The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdon Of Great Britain And Northern Ireland | Thermal detector |
| US4791298A (en) * | 1986-02-14 | 1988-12-13 | U.S. Philips Corp. | Infrared detectors |
| GB2205442A (en) * | 1987-05-27 | 1988-12-07 | Marconi Co Ltd | Manufacture of infra-red detectors |
| EP0293216A2 (en) * | 1987-05-27 | 1988-11-30 | The Marconi Company Limited | Manufacture of infra-red detectors |
| EP0293216A3 (en) * | 1987-05-27 | 1990-11-07 | The Marconi Company Limited | Manufacture of infra-red detectors |
| GB2372630A (en) * | 1988-03-29 | 2002-08-28 | Santa Barbara Res Ct | Epitaxial passivation of group 2-6 infrared photodetectors |
| GB2372630B (en) * | 1988-03-29 | 2003-01-15 | Santa Barbara Res Ct | Epitaxial passivation ofgroup II-VI infrared photodetectors |
| DE3915321C1 (en) * | 1988-05-11 | 2000-12-28 | Raytheon Co | Method for forming a passivation area on a semiconductor device from a II-VI connection and application of the method |
| EP2051303A2 (en) * | 2007-08-28 | 2009-04-22 | Biomimetics Technologies Inc. | Method to detect poor infrared rays, Microchip that is able to detect poor infrared rays and apparatus working with these microchips |
| EP2051303A3 (en) * | 2007-08-28 | 2014-12-17 | Biomimetics Technologies Inc. | Method to detect poor infrared rays, Microchip that is able to detect poor infrared rays and apparatus working with these microchips |
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| GB1571492A (en) | Fabrication of solid state devices | |
| JPS5938730B2 (en) | Manufacturing method of semiconductor device |
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| PE20 | Patent expired after termination of 20 years |
Effective date: 19961021 |