Thz detection employing modulation doped quantum well device structures

• US 20050230705A1
• Filed: 04/28/2003
• Published: 10/20/2005
• Est. Priority Date: 04/26/2002
• Status: Active Grant

• Current Assignee: OPEL Solar, Inc. (POET Technologies Inc.), University of Connecticut (State of Connecticut)
• Original Assignee: OPEL, Inc. (POET Technologies Inc.), University of Connecticut (State of Connecticut)
• Inventors: Taylor, Geoff w.
• Granted Patent: US 7,262,429 B2
• Time in Patent Office: Days
• US Class Current: 257/120
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14658 X-ray, gamma-ray or corpuscular radiation imagers measuring X-, gamma- or corpuscular radiation G01T1/00
• CPC Class Codes: H01L 27/14806 Structural or functional details thereof
• CPC Class Codes: H01L 27/14843 Interline transfer
• CPC Class Codes: H01L 27/1485 Frame transfer
• CPC Class Codes: H01L 29/205 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 29/74 Thyristor-type devices, e.g. having four-zone regenerative action two-terminal thyristors H01L29/87
• CPC Class Codes: H01L 31/03046 including ternary or quaternary compounds, e.g. GaAlAs, InGaAs, InGaAsP
• CPC Class Codes: H01L 31/035236 Superlattices; Multiple quantum well structures
• CPC Class Codes: H01L 31/035263 Doping superlattices, e.g. nipi superlattices
• CPC Class Codes: H01L 31/111 characterised by at least three potential barriers, e.g. photothyristors
• CPC Class Codes: H01L 31/115 Devices sensitive to very short wavelength, e.g. X-rays, gamma-rays or corpuscular radiation
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials

Abstract

An improved THz detection mechanism includes a heterojunction thyristor structure logically formed by an n-type quantum-well-base bipolar transistor and p-type quantum-wellbase bipolar transistor arranged vertically to share a common collector region. Antenna elements, which are adapted to receive electromagnetic radiation in a desired portion of the THz region, are electrically coupled (or integrally formed with) the p-channel injector electrodes of the heterojunction thyristor device such the that antenna elements are electrically connected to the p-type modulation doped quantum well interface of the device. THz radiation supplied by the antenna elements to the p-type quantum well interface increases electron temperature of a two-dimensional electron gas at the p-type modulation doped quantum well interface thereby producing a current resulting from thermionic emission over a potential barrier provided by said first-type modulation doped quantum well interface. This current flows over the p-type channel barrier to the ntype quantum well interface, thereby causing charge to accumulate in the n-type quantum well interface. The accumulated charge in the n-type quantum well interface is related to the intensity of the received THz radiation. The heterojunction-thyristor-based THz detector is suitable for many applications, including data communication applications and imaging applications.

Claims

1. An electronic device comprising:

a first-type modulation doped quantum well interface and a second-type modulation doped quantum well interface that are formed over a substrate and spaced apart from one another,

at least one antenna element which is adapted to receive electromagnetic radiation in a desired portion of a THz region between 100 GHz and 10,000 GHz, said antenna element electrically coupled to said first-type modulation doped quantum well interface.

2. An electronic device according to claim 1, wherein:

THz electromagnetic radiation received by said antenna element is supplied to said first-type modulation doped quantum well interface and increases electron temperature of a two-dimensional electron gas at said first-type modulation doped quantum well interface thereby producing a current resulting from thermionic emission over a potential barrier provided by said first-type modulation doped quantum well interface, wherein said current results in accumulation of charge in said second-type modulation doped quantum well interface.

3. An electronic device according to claim 2, wherein:

said current is proportional to power of the received THz electromagnetic radiation.

4. An electronic device according to claim 1, wherein:

said first-type modulation doped quantum well interface and said second-type modulation doped quantum well interface are spaced apart from one another in a vertical dimension.

5. An electronic device according to claim 1, wherein:

said electromagnetic radiation comprises a THz carrier wave modulated in accordance with a data stream.

6. An electronic device according to claim 1, wherein:

charge is accumulated in said second-type modulation doped quantum well interface over an integration time period for subsequent readout therefrom.

7. An electric device according to claim 1, wherein:

said first-type modulation doped quantum well interface and said second-type modulation doped quantum well interface are spaced apart from one another in a vertical dimension.

8. An electronic device according to claim 7, further comprising:

an undoped spacer layer disposed between said first-type modulation doped quantum well interface and said second-type modulation doped quantum well interface.

9. An electronic device according to claim 8, further comprising:

first-type ions implants in electrical contact with said first-type modulation doped quantum well interface; and

second-type ions implants in electrical contact with said second-type modulation doped quantum well interface.

10. An electronic device according to claim 9, further comprising:

first channel injector terminals formed from a metal layer deposited on said first-type ion implants; and

second channel injector terminals formed from a metal layer deposited on said second-type ion implants.

11. An electronic device according to claim 10, further comprising:

an anode and cathode formed such that said first-type modulation doped quantum well interface and said second-type modulation doped quantum well interface are disposed between said anode and said cathode;

an anode terminal electrically coupled to said anode; and

a cathode terminal electrically coupled to said cathode to thereby integrally form a thyristor device on said substrate.

12. An electronic device according to claim 11, further comprising:

a current source, electrically coupled to said second-type modulation doped quantum well interface, providing a bias current that draws charge from said second-type modulation doped quantum well interface.

13. An electronic device according to claim 11, wherein:

said THz electromagnetic radiation comprises bursts of THz energy transmitted according to an On/Off Keying wherein a first digital logic value is provided by a series of N THz pulses in a unit of time and a second digital logic value is provided by absence of said series of N THz pulses in said unit of time.

14. An electronic device according to claim 13, wherein:

said thyristor device is adapted to switch into an ON/conducting state in response to the detection of THz electromagnetic radiation that represents said first digital logic value and to switch into an OFF/non-conducting state in response to detection of THz electromagnetic radiation that represents said second digital logic value.

15. An electronic device according to claim 14, further comprising:

a current source, electrically coupled to said second-type modulation doped quantum well interface, providing a bias current that draws charge from said second-type modulation doped quantum well interface, wherein said bias current is set such that;

i) accumulated charge in said second modulation doped quantum well interface that results from the reception of THz electromagnetic radiation that represents said first digital logic value in a predetermined time interval exceeds a critical switching charge of said thyristor device, and

ii) accumulated charge in said second modulation doped quantum well interface that results from the reception of THz electromagnetic radiation that represents said second digital logic value in a predetermined time interval falls below a holding charge of said thyristor device.

16. An electronic device according to claim 14, further comprising:

load resistance, operably coupled to said thyristor device, that provides a current I through said thyristor device when operating in said ON/conducting state, said current I greater than a characteristic hold current of said thyristor device.

17. An electronic device according to claim 14, wherein:

said thyristor device produces a differential electrical signal between its cathode terminal and ground potential that corresponds to the detection of THz radiation representing said first and second digital logic values, respectively.

18. An electronic device according to claim 14, wherein:

said load resistance provides a current I through said thyristor device when operating in said ON/conducting state that is greater than the threshold lasing current of said thyristor device.

19. An electronic device according to claim 18, wherein:

said thyristor device produces an optical digital signal in an active area of said thyristor device that corresponds to the detection of THz radiation representing said first and second digital logic values, respectively.

20. An electronic device according to claim 11, wherein:

said thyristor device and at least one antenna element are adapted to perform a plurality of successive imaging cycles, wherein during each imaging cycle

i) initially said second-type modulation doped quantum well interface is emptied of charge,

ii) over an integration time period, charge is accumulated in said second-type modulation doped quantum well interface in response to received THz radiation, and

iii) subsequent to said integration time period, accumulated charge stored in said second-type modulation doped quantum well interface is output therefrom.

21. An electronic device according to claim 20, further comprising:

a plurality of pixel elements that each include said thyristor device and said at least one antenna element.

22. An electronic device according to claim 21, wherein:

said plurality of pixel elements are part of a full-frame-type imaging array.

23. An electronic device according to claim 21, wherein:

said plurality of pixel elements are part of an interline-type imaging array.

24. An electronic device according to claim 21, wherein:

said plurality of pixel elements are part of an active-pixel-type imaging array.

25. An electronic device comprising:

a bipolar-type transistor comprising an emitter terminal, collector terminal, and at least one base terminal coupled to a modulation doped quantum well interface;

at least one antenna element which is adapted to receive electromagnetic radiation in a desired portion of a THz region between 100 GHz and 10,000 GHz, said antenna element electrically coupled to said modulation doped quantum well interface via said at least one base terminal.

26. An electronic device according to claim 25, wherein:

THz electromagnetic radiation received by said antenna element is supplied to said modulation doped quantum well interface and increases the electron temperature of a two dimensional electron gas at said modulation doped quantum well interface thereby producing a current resulting from thermionic emission over a potential barrier provided by said modulation doped quantum well interface, wherein said current is output via the collector terminal of said bipolar-type transistor.

27. An electronic device according to claim 25, wherein:

said current is proportional to power of the received THz electromagnetic radiation.

28. An electronic device comprising:

a modulation doped quantum well interface; and

at least one antenna element which is adopted to receive electromagnetic radiation in a desired portion of a THz region between 100 GHz and 10,000 GHz, said antenna element electrically coupled to said modulation doped quantum well interface.

29. An electronic device according to claim 28, wherein:

THz electromagnetic radiation received by said antenna element is supplied to said modulation doped quantum well interface and increases the electron temperature of a two-dimensional electron gas at said modulation doped quantum well interface thereby producing a current resulting from thermionic emission over a potential barrier provided by said modulation doped quantum well interface.

30. An electronic device according to claim 29, wherein:

said current is proportional to power of the received THz electromagnetic radiation.