EP0555402A1 - Detecteur a infrarouge a puits quantiques et a transport de minibande - Google Patents

Detecteur a infrarouge a puits quantiques et a transport de minibande

Info

Publication number
EP0555402A1
EP0555402A1 EP92902033A EP92902033A EP0555402A1 EP 0555402 A1 EP0555402 A1 EP 0555402A1 EP 92902033 A EP92902033 A EP 92902033A EP 92902033 A EP92902033 A EP 92902033A EP 0555402 A1 EP0555402 A1 EP 0555402A1
Authority
EP
European Patent Office
Prior art keywords
miniband
layers
barrier layers
transport
quantum wells
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Withdrawn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
EP92902033A
Other languages
German (de)
English (en)
Inventor
John William Little, Jr.
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.)
Martin Marietta Corp
Original Assignee
Martin Marietta Corp
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 Martin Marietta Corp filed Critical Martin Marietta Corp
Publication of EP0555402A1 publication Critical patent/EP0555402A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • 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
    • H01L31/0248—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 characterised by their semiconductor bodies
    • H01L31/0352—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 characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
    • 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
    • H01L31/0248—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 characterised by their semiconductor bodies
    • H01L31/0352—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 characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
    • H01L31/035236—Superlattices; Multiple quantum well structures
    • 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

Definitions

  • the present invention is directed to a semiconductor infrared detector and a method of detecting thermal radiation and more particularly to a semiconductor infrared detector having a plurality of doped quantum wells separated by short period superlattice layers which form a miniband of energy states.
  • High performance detectors and detector arrays for detecting thermal radiation are used in a wide variety of military and commercial electro-optic system such as night vision, military surveilance and navigation, the tracking of missiles and aircraft and navigational aids for commercial aircrafts.
  • Detectors in the medium wavelength infrared (MWIR) wavelength band have a number of detector materials that are available to be used.
  • detectors in the long wavelength infrared (LWIR) wavelength band have only been able to be fabricated with a narrow band gap semiconductor of mercury cadmium telluride (MCT) .
  • MCT mercury cadmium telluride
  • QWIP quantum well infrared photo- detectors
  • the QWIP detector of Figure 1 includes a stack of quantum wells having widths and depths chosen to provide two confined states, the ground state and the excited state as illustrated in Figure la.
  • the energy separation between the ground state and the excited state is equal to the energy of the photon to be detected.
  • the quantum walls are doped with electron donor impurities which partially fill the lowest energy state with electrons.
  • a barrier having- a thickness of approximately one hundred angstroms (100 ) separates each of the quantum walls.
  • the quantum well there is only one bound state i the quantum well and the first excited state must be clos in energy to the top of the barrier because the absorptio strength drops rapidly as the excited state moves highe above the barrier which reduces the detectivity.
  • the well width and barrier height are uniquely defined and therefore cannot be varied to optimize detector performance.
  • the effective mass of the carriers must be low in order to provide one bound state in the quantum well.
  • the dopants in the QWIP detector must be n-type (electro donors) which further limits the design parameters.
  • the wavelength range in which the QWI detector is sensitive is primarily a material parameter that is determined by the wavelength dependence of th process of absorption from " a discrete state to th continuum, and the wavelength range can only be changed b varying the energy of the excited state above the. barrier which greatly decreases the absorption strength.
  • One object of the present invention is to provide an improved semiconductor device for detecting thermal radiation. It is a further object of the present invention to provide a miniband transport quantum well infrared semiconductor detector having a predetermined bandwidth corresponding to the range of wavelengths to which the detector is sensitive that is determined by the thickness and composition of the semiconductor layers of the detector.
  • Another object of the present invention is to obtain an electrically tunable peak absorption and bandwidth in response to an electric field applied to the detector.
  • a semiconductor miniband transport quantum well infrared detector comprising a substrate, a multilayer structure disposed on the substrate, and first and second contact layers disposed on. the top and bottom surfaces of the multilayer structure.
  • the multilayer structure includes a plurality of doped quantum wells and superlattice barrier layers disposed on each side of the quantum wells.
  • the superlattice barrier layers comprise a plurality of alternating first and second layers wherein the first layers have a relatively low band gap and the second layers have a relatively high band gap.
  • the superlattice barrier layers form a miniband of energy states which transport photoexcited carriers from the quantum wells for collection as photocurrent.
  • the semiconductor detector of the presen invention comprises quantum wells having two or more boun states so that a wide range of materials and carrier type may be used for the semiconductor layers.
  • the semiconducto detector comprises a GaAs/AlGaAs quantum well system.
  • a wide range of semiconducto materials for the detector may be used such a inGaAs/InAlAs (lattice-matched to InP substrates) o InGaAs/InAlGaAs strained layer systems for example.
  • the present invention additionally provides method for detecting thermal radiation by a semiconducto device comprising the steps of providing a plurality o doped quantum well layers, forming a miniband from plurality of strongly coupled superlattice barrier layer disposed on each of the quantum well layers, photoexcitin carriers from the quantum wells to the miniband an applying an electric field across the superlattice barrie layers and the quantum well layers to transport th carriers through the miniband for collection as photocurrent corresponding to the thermal radiation.
  • semiconductor detector and a method is provided whic allows the quantum wells to be formed with more than on bound state and a wide variety of well widths and barrie heights.
  • the superlattice barrier layers reduce the dar current and the sensitivity to processing variations b using wider quantum wells.
  • a larger range o materials and carrier types may be used for th detectors.
  • the bandwidth of the detector may be selected over a wide range by varying the coupling o the layers in the superlattice barrier to provide broader or narrower miniband as desired which broadens or narrows the absorption range respectively while maintaining the absorption strength.
  • Figures la and lb illustrate the energy states of a conventional quantum well infrared photodetector where no bias is applied to the detector in Figure la and a bias is applied to the detector in Figure lb;
  • Figures 2a and 2b illustrate the energy states of another conventional quantum well infrared photodetector where no bias is applied to the detector in Figure 2a and a bias is applied to the detector in Figure 2b;
  • Figure 3 illustrates the structure for the miniband transport quantum well infrared detector for an embodiment of the present invention
  • Figure 4 illustrates a miniband transport quantum well infrared detector for an embodiment of the present invention which utilizes the semiconductor structure of Figure 3
  • Figures 5a and 5b illustrate the energy states for the miniband transport detector for the present invention where no bias is applied in Figure 5a and a bias is applied in Figure 5b;
  • Figure 6 illustrates the wavelength dependence of photocurrent obtained from a miniband transport detector of the present invention.
  • Figure 7 illustrates the bias dependence of the detectivity of the miniband transport detector of the present invention.
  • FIG. 3 is first referred to and illustrates an embodiment of the structure for a miniband transport quantum well infrared detector (hereinafter referred to as MBT detector).
  • the MBT detector is formed of a multilayer structure 40 which has alternating quantum wells 10 ⁇ , 10,, . . . 10 and superlattice barrier layers 20., 20,, . . . 20 n*
  • a capping layer 60 and a buried contact 70 are disposed on each end of the multilayer structure 40.
  • the above described structure is formed on a substrate 30.
  • FIG. 4 illustrates an embodiment of the present invention which includes an array of detector elements (pixels) .
  • Each pixel is delineated and the buried contact is exposed by etching away the material surrounding the pixels.
  • Each pixel includes a layer 80 having an optical diffraction grating etched into the capping layer 60 and a metal contact deposited on the surface of the optical diffraction grating. Radiation is incident through the substrate 30 and is coupled into the detector layers by the optical diffraction grating.
  • the quantum wells of the MBT detector contain two or more bound states which include at least a ground state and an excited state. A miniband of energy states is formed by strongly coupling the superlattice layers of the structure.
  • the superlattice barrier layers include a plurality of thin quantum wells separated by thin barrier layers. These plurality of layers correspond to alternating low band gap layers and high band gap layers which are chosen so that the lowest energy miniband is in resonance with the excited state of the quantum wells.
  • An example of this structure is illustrated in
  • Figure 5a where the quantum well includes a ground state and an excited state which falls between the energy levels of the miniband 100.
  • Figure 5b illustrates the application of an electric field to the structure wherein the minibahd is tilted and breaks up into a series of quasi-discrete states (not shown in the figures) extending through several periods of the superlattice layers.
  • the quantum wells are doped so that the ground states are partially filled with carriers.
  • the carriers in the ground states of the quantum wells may thereby be excited into the next higher energy state (or any odd order energy state as dictated by selection rules for optical transition) by infrared photons.
  • the carriers are placed in the miniband which allows the carriers to move through the barrier layers with relatively ease for collection as photocurrent in the contact layers.
  • the superlattice barrier layers may be made of a thickness so that the probability of carriers tunneling directly from the ground state into the next quantum well or into the continuum is substantially zero except when very high biases are applied to the structure. In other words, the tunneling components of the dark current is approximately zero.
  • the energy of the superlattice barrier layers may be chosen to be sufficiently large for limiting the thermionic emission of carriers into the continuum at the desired operating temperature of 77 Kelvin.
  • the precise quantum well and superlattice barrier layer geometry is determined by solving the Schroedinger equation for the system in order to obtain the desired wavelength peak and range in the responsitivity of the detector.
  • the number of layers in the superlattice barrier layers are chosen based on the crystal growth time or other similar considerations.
  • the quantum well layers are doped so that the ground states are partially filled with carriers where the layers are usually doped with electron donors.
  • the energy and the spatial extents of the quasi-discrete states in the miniband are strong functions of the applied electric field.
  • properties of the MBT detector such as the peak absorption and the responsitivity bandwidth may be electrically tuned.
  • an MBT detector that was formed by molecular beam epitaxy includes forty GaAs quantum wells, which have a thickness of approximately 78 and are doped with silicon to a level of 4x10 17/cm3, separated by superlattice barrier layers having nine GaAs wells, approximately 20 A thick, and ten AlGaAs barriers, approximately 40 & thick. Doped contact layers having a thickness of 1 ⁇ m were formed above and below the active quantum well regions. Detector elements having various areas were thereafter defined by chemical etching in order to form ohmic metalization areas. A conventional 4 ⁇ m pitch triangular grating is etched into the back of the wafer in order to collect light with a polarization component perpendicular to the quantum well layers.
  • the MBT detector is not restricted to this specific GaAs-AlGaAs quantum well system.
  • a wide variety of layers, layer thicknesses and materials may be used for the MBT detector.
  • InGaAs/InAlAs laattice matched to InP substrates
  • InGaAs/InAlGaAs strained layer systems may be used.
  • the widths of the quantum wells and the thicknesses of the superlattice barrier layers may range from one monolayer to several hundred Angstroms.
  • the wavelength sensitivity is determined by material parameters such as the effective mass, band offsets and the well depths.
  • the structure of the present invention allows the use of p-type acceptor doping in the quantum wells. As a result, the higher effective mass of the p-type carriers reduces the dark current of the device by reducing the Fermi level and the corresponding thermionic emission.
  • Figures 6 and 7 illustrate the improved characteristics of the MBT detector of the present invention.
  • Figure 6 illustrates the wavelength dependence of the photocurrent which has a peak response of about 10.5 / um and a long wavelength cutoff (a half power point) of 11.1Am.
  • Figure 7 illustrates the bias dependence of the peak detectivity at a temperature of 77 Kelvin which obtains a value of 1x10 cm J HzVw.
  • the embodiments of the present invention provide an infrared detector for collecting photocurrent by quantum wells having a wide range of depths and widths. Because the MBT detectors allow materials having more than one bound state for the quantum wells to be used, the range of materials and carrier types are greater. Furthermore, the bandwidth of the MBT detector may be selected over a wide range by strongly coupling the superlattice barriers layers to provide a broader miniband which increases the absorption range while maintaining the strength of absorption in the quasi-bound state. Accordingly, an enhanced semiconductor device and a method for detecting thermal radiation is provided in the present invention.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computer Hardware Design (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Nanotechnology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biophysics (AREA)
  • Optics & Photonics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Light Receiving Elements (AREA)

Abstract

Un dispositif à semi-conducteur servant à détecter les rayonnements comprend une multiplicité de puits quantiques dopés présentant au moins deux états liés qui sont entourés par une multiplicité de couches d'arrêt en forme de super-réseau et présentant une minibande dont l'énergie moyenne est approxivmativement égale à l'un des états liés des puits quantiques. Des porteurs photoexcités de l'état fondamental aux états excités des puits quantiques dopés sont balayés dans la minibande par un champ électrique appliqué de l'extérieur afin qu'ils soient amassés sous forme d'un photocourant. En conséquence, une large plage de largeurs de puits quantiques et de hauteurs de barrière ainsi qu'une variété de matériaux et de types de porteurs peuvent être utilisés, de sorte qu'il en résulte un procédé de fabrication plus aisé du dispositif à semi-conducteur ainsi que des caractéristiques de dispositif améliorées telles qu'un courant d'obscurité plus bas.
EP92902033A 1990-10-31 1991-10-24 Detecteur a infrarouge a puits quantiques et a transport de minibande Withdrawn EP0555402A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US60628590A 1990-10-31 1990-10-31
US606285 1996-02-23

Publications (1)

Publication Number Publication Date
EP0555402A1 true EP0555402A1 (fr) 1993-08-18

Family

ID=24427344

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92902033A Withdrawn EP0555402A1 (fr) 1990-10-31 1991-10-24 Detecteur a infrarouge a puits quantiques et a transport de minibande

Country Status (6)

Country Link
EP (1) EP0555402A1 (fr)
JP (1) JPH06502743A (fr)
AU (1) AU9030791A (fr)
CA (1) CA2091053A1 (fr)
IL (1) IL99855A0 (fr)
WO (1) WO1992008250A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL106130A (en) * 1992-06-30 1996-10-19 Martin Marietta Corp Detector with minimal stripe transport of quantum sources and a method for detecting electromagnetic radiation
US5477060A (en) * 1993-06-25 1995-12-19 The United States Of America As Represented By The Secretary Of The Army Infrared hot electron transistor with a superlattice base
FR2729789B1 (fr) * 1993-09-10 1998-03-20 Thomson Csf Detecteur a puits quantique et procede de realisation
GB2298735A (en) * 1995-03-08 1996-09-11 Sharp Kk Semiconductor device having a miniband
US5539206A (en) * 1995-04-20 1996-07-23 Loral Vought Systems Corporation Enhanced quantum well infrared photodetector
SG68636A1 (en) * 1997-09-27 1999-11-16 Univ Singapore Dual band infrared detector using step multiquantum wells with superlattice barriers
US6054718A (en) * 1998-03-31 2000-04-25 Lockheed Martin Corporation Quantum well infrared photocathode having negative electron affinity surface
JP5282361B2 (ja) * 2007-02-19 2013-09-04 富士通株式会社 量子井戸型光検知器及びその製造方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0821748B2 (ja) * 1985-09-04 1996-03-04 株式会社日立製作所 半導体レ−ザ装置
US4894526A (en) * 1987-01-15 1990-01-16 American Telephone And Telegraph Company, At&T Bell Laboratories Infrared-radiation detector device
US5047822A (en) * 1988-03-24 1991-09-10 Martin Marietta Corporation Electro-optic quantum well device
CA1314614C (fr) * 1988-06-06 1993-03-16 Clyde George Bethea Detecteur de rayonnement par puits quantiques
EP0380939B1 (fr) * 1989-01-31 1995-12-06 International Business Machines Corporation Photodétecteur à effet tunnel résonnant pour utilisation à grandes longueurs d'onde

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9208250A1 *

Also Published As

Publication number Publication date
JPH06502743A (ja) 1994-03-24
AU9030791A (en) 1992-05-26
IL99855A0 (en) 1992-08-18
WO1992008250A1 (fr) 1992-05-14
CA2091053A1 (fr) 1992-05-01

Similar Documents

Publication Publication Date Title
JP3542965B2 (ja) デュアルバンド量子井戸赤外線センシングアレイ
US4894526A (en) Infrared-radiation detector device
US6455908B1 (en) Multispectral radiation detectors using strain-compensating superlattices
US8674406B2 (en) Extended wavelength digital alloy NBN detector
US7271405B2 (en) Intersubband detector with avalanche multiplier region
US5023685A (en) Quantum-well radiation-interactive device, and methods of radiation detection and modulation
US4775881A (en) Semiconductor device for detecting electromagnetic radiation or particles
US20110156097A1 (en) Reduced dark current photodetector
US8697554B2 (en) Lateral collection architecture for SLS detectors
US5198682A (en) Multiple quantum well superlattice infrared detector with graded conductive band
US4711857A (en) Tailorable infrared sensing device with strain layer superlattice structure
US5510627A (en) Infrared-to-visible converter
US5313073A (en) Light detector using intersub-valence band transitions with strained barriers
US5965899A (en) Miniband transport quantum well detector
US4486765A (en) Avalanche photodetector including means for separating electrons and holes
US5969375A (en) Infrared detector with non-cooled quantum well structure
US5296720A (en) Apparatus and method for discriminating against undesired radiation in a multiple quantum well long wavelength infrared detector
US20140217540A1 (en) Fully depleted diode passivation active passivation architecture
KR920009918B1 (ko) 양자-웰 방사선 검출 소자
EP0555402A1 (fr) Detecteur a infrarouge a puits quantiques et a transport de minibande
US5352904A (en) Multiple quantum well superlattice infrared detector with low dark current and high quantum efficiency
US4843439A (en) Tailorable infrared sensing device with strain layer superlattice structure
JP2000188407A (ja) 赤外線検知素子
Bois et al. Technology of multiple quantum well infrared detectors
EP0648377B1 (fr) Detecteur a puits quantiques et a transport par minibande

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19930419

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19930730