GB2186074A - Photodetector with associated diffraction grating - Google Patents

Photodetector with associated diffraction grating Download PDF

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Publication number
GB2186074A
GB2186074A GB08602525A GB8602525A GB2186074A GB 2186074 A GB2186074 A GB 2186074A GB 08602525 A GB08602525 A GB 08602525A GB 8602525 A GB8602525 A GB 8602525A GB 2186074 A GB2186074 A GB 2186074A
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GB
United Kingdom
Prior art keywords
light
detector
incident
angle
incidence
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08602525A
Other versions
GB8602525D0 (en
Inventor
Craig George Sawyers
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PA Consulting Services Ltd
Original Assignee
PA Consulting Services Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by PA Consulting Services Ltd filed Critical PA Consulting Services Ltd
Priority to GB08602525A priority Critical patent/GB2186074A/en
Publication of GB8602525D0 publication Critical patent/GB8602525D0/en
Priority to EP87901071A priority patent/EP0256074A1/en
Priority to JP62500985A priority patent/JPS63502631A/en
Priority to PCT/GB1987/000060 priority patent/WO1987004861A1/en
Publication of GB2186074A publication Critical patent/GB2186074A/en
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • H01L31/10—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 characterised by potential barriers, e.g. phototransistors
    • H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
    • H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
    • H01L31/108—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the Schottky type
    • 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
    • H01L31/02—Details
    • H01L31/0216—Coatings
    • H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
    • 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
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device
    • H01L31/02325—Optical elements or arrangements associated with the device the optical elements not being integrated nor being directly associated with the device
    • 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
    • H01L31/02—Details
    • H01L31/0236—Special surface textures
    • 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
    • H01L31/02—Details
    • H01L31/0236—Special surface textures
    • H01L31/02363—Special surface textures of the semiconductor body itself, e.g. textured active layers

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Light Receiving Elements (AREA)

Abstract

A photodetector which comprises a surface-profiled Schottky barrier detector (22) having a peak response which is a function of wavelength and of angle of incidence, and a blazed diffraction grating (20) positioned in front of the barrier detector and having its dispersion selected so that its first order of diffracted light is incident on the barrier detector with an angle of incidence (A1, A2) which so varies as substantially to compensate for the peak response function of the barrier detector, thereby to produce a peak response from the barrier detector throughout a range of wavelengths. In this way, the bandwidth of the photodector can be controlled.

Description

SPECIFICATION Light detector Field of invention This invention concerns light detectors and is particularly concerned with the design of a wideband detector capable of responding to light over a range of wavelengths.
Background to the invention A preferred form of photodetector is a Schottky barrier device. It is known to profile the surface of such devices with the result that the device exhibits a peak response as a function of the angle of incidence and wavelength of the incident light.
The advantage of a Schottky barrier detector having a profiled surface is the high speed of response, combined with the ease of fabrication. However, the response bandwidth for a given angle of incidence is very narrow~ typically 5-50 nm, and it is an object of the present invention to provide a design of such a device which posseses a greater response bandwidth.
Summary of the invention According to the present invention a photodetector comprises: 1. a Schottky barrier detector having a profiled surface which exhibits a high response to incident light whose wavelength and angle of incidence satisfy an equation of the form f (wavelength, angle of incidence)=K, 2. a blazed diffraction grating which will efficiently diffract the first diffracted order of light incident thereon, and whose dispersion is chosen to compensate for the variation in angle of incidence with wavelength of the response peak of the detector, 3. means for projecting or otherwise causing input light to be incident on the diffraction grating, 4. means positioning the grating relative to the profiled detector surface so that any first order light from the grating (caused by input light incident thereon), will be diffracted so as to be incident on the profiled surface of the detector.
The resulting combination of blazed diffraction grating and Schottky barrier detector will have a high response to any input light where wavelength is within the range of compensation provided by the dispersion of the grating.
By careful choice of the dispersion, so the bandwidth of the combination can be con trolley.
The invention will be described by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a typical profiled Schottky barrier detector construction, with light incident thereon, Figure 2 is a graphical representation of the response of such a device to change of wavelength and angle of incidence, and Figure 3 shows diagrammatically an arrangement of grating and detector in accordance with the invention.
In Fig. 1 two beams of light one of wavelength L1 and the other L2 are incident on a profiled surface 10 of a metalised silicon substrate 12, the metal layer being denoted by 14.
If the response is mapped against angle of incidence (with constant wavelength), it is found that, a peak in the detector output occurs at one particular angle, likewise if respons is mapped against changing wavelength, a peak is obtained at one particular wavelength if the angle of incidence remains constant.
Fig. 2 shows the detector response against changing wavelength for two different angles of incidence Al and A2. The curve 16 shows the response for the angle of incidence Al and curve 18 that of an angle of incidence A2.
Fig. 3 shows an arrangement of blazed grating 20 and detector 22 (which typically comprises a silicon substrate having a profiled upper surface which is coated by a thin metal layer, as shown in Fig. 1. By arranging that the dispersion characteristic of the blazed grating is such that first order diffracted light is efficiently diffracted towards the detector at varying angles so that the angle is incidence, according to wavelength, is such as is necessary to produce a peak response in the detector, for each wavelength concerned, so a range of wavelengths of light incident on the grating 20 will produce peak responses in the detector 22.
As shown in Fig. 3, two components 24, 26 of light of wavelength L1 and L2 are shown arriving in parallel at the grating 20 and thereafter are seen to diverge at 28 and 30 respectively to be incident on the detector 22 at different angles of incidence Al and A2 respectively. Where there are the correct angles of incidence for those wavelengths, a peak response is obtained from the detector for both.
Since the blazed grating will treat all wavelengths intermediate L1 and L2 in a similar manner, and cause differing divergencies and therefore differing angles of incidence in the detector, so a peak level of response can be obtained for all the wavelengths concerned.

Claims (5)

1. A photodetector comprising -a Schottky barrier detector having a profiled surface which exhibits a peak response to incident light as a fraction of the wavelength of the light and of its angle of incidence; -a blazed diffraction grating which, in respect of the first diffracted order of light within a range of wavelengths incident thereon, has a dispersion chosen substantially to compensate for the variation in angle of incidence with wavelength of the peak response of the detector; ~means for projecting or otherwise causing input light to be incident on the diffraction grating; and ~means positioning the grating relative to the profiled detector surface so that first order light from the grating (caused by input light incident thereon), will be diffracted so as to be incident on the profiled surface of the detector.
2. A photodetector according to claim 1, wherein the Schottky barrier detector comprises a silicon substrate having a profiled surface with a thin metal layer of uniiform thickness deposited on said profiled surface.
3. A photodetector substantially as hereinbefore described with reference to the accompanying drawings.
4. A method of photodetection according to which a blazed diffraction grating is positioned in an incident beam of multiple wavelength light to direct the first order of diffracted light on to a Schottky barrier detector which exhibits a peak response as a function of the wavelength of the light and its angle of incidence on said barrier detector, and the diffraction grating has a dispersion such that, at least within a range of wavelengths, the angle at which light is incident on the barrier detector so varies as substantially to compensate the peak response function of said barrier detector and thereby produce a peak response throughout said range of wavelengths.
5. A method of photodetection substantially as hereinbefore described.
GB08602525A 1986-02-01 1986-02-01 Photodetector with associated diffraction grating Withdrawn GB2186074A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
GB08602525A GB2186074A (en) 1986-02-01 1986-02-01 Photodetector with associated diffraction grating
EP87901071A EP0256074A1 (en) 1986-02-01 1987-01-29 Light detector
JP62500985A JPS63502631A (en) 1986-02-01 1987-01-29 photodetector
PCT/GB1987/000060 WO1987004861A1 (en) 1986-02-01 1987-01-29 Light detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08602525A GB2186074A (en) 1986-02-01 1986-02-01 Photodetector with associated diffraction grating

Publications (2)

Publication Number Publication Date
GB8602525D0 GB8602525D0 (en) 1986-03-05
GB2186074A true GB2186074A (en) 1987-08-05

Family

ID=10592389

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08602525A Withdrawn GB2186074A (en) 1986-02-01 1986-02-01 Photodetector with associated diffraction grating

Country Status (4)

Country Link
EP (1) EP0256074A1 (en)
JP (1) JPS63502631A (en)
GB (1) GB2186074A (en)
WO (1) WO1987004861A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989006051A1 (en) * 1987-12-17 1989-06-29 Unisearch Limited Improved optical properties of solar cells using tilted geometrical features

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6076565A (en) * 1997-08-08 2000-06-20 Theodore Sweeney & Company Adhesive fastener and method
US6012888A (en) * 1997-08-08 2000-01-11 Theodore Sweeney & Co. Adhesive fastener and method

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4343532A (en) * 1980-06-16 1982-08-10 General Dynamics, Pomona Division Dual directional wavelength demultiplexer
FR2536911B1 (en) * 1982-11-30 1987-09-18 Western Electric Co PHOTODETECTOR

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989006051A1 (en) * 1987-12-17 1989-06-29 Unisearch Limited Improved optical properties of solar cells using tilted geometrical features
AU612226B2 (en) * 1987-12-17 1991-07-04 Unisearch Limited Solar cells with tilted geometrical features
US5080725A (en) * 1987-12-17 1992-01-14 Unisearch Limited Optical properties of solar cells using tilted geometrical features

Also Published As

Publication number Publication date
JPS63502631A (en) 1988-09-29
GB8602525D0 (en) 1986-03-05
EP0256074A1 (en) 1988-02-24
WO1987004861A1 (en) 1987-08-13

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)