EP0416626A2 - Elektronenemittierende Halbleitervorrichtung - Google Patents

Elektronenemittierende Halbleitervorrichtung Download PDF

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Publication number
EP0416626A2
EP0416626A2 EP90117200A EP90117200A EP0416626A2 EP 0416626 A2 EP0416626 A2 EP 0416626A2 EP 90117200 A EP90117200 A EP 90117200A EP 90117200 A EP90117200 A EP 90117200A EP 0416626 A2 EP0416626 A2 EP 0416626A2
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EP
European Patent Office
Prior art keywords
electron emitting
semiconductor device
area
emitting semiconductor
barrier electrode
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.)
Granted
Application number
EP90117200A
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English (en)
French (fr)
Other versions
EP0416626A3 (en
EP0416626B1 (de
Inventor
Toshihiko C/O Canon Kabushiki Kaisha Takeda
Takeo C/O Canon Kabushiki Kaisha Tsukamoto
Nobuo C/O Canon Kabushiki Kaisha Watanabe
Masahiko C/O Canon Kabushiki Kaisha Okunuki
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.)
Canon Inc
Original Assignee
Canon Inc
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
Priority claimed from JP23394589A external-priority patent/JP2820450B2/ja
Priority claimed from JP1233943A external-priority patent/JPH0395825A/ja
Priority claimed from JP2221713A external-priority patent/JPH04102373A/ja
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP0416626A2 publication Critical patent/EP0416626A2/de
Publication of EP0416626A3 publication Critical patent/EP0416626A3/en
Application granted granted Critical
Publication of EP0416626B1 publication Critical patent/EP0416626B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/30—Cold cathodes, e.g. field-emissive cathode
    • H01J1/308—Semiconductor cathodes, e.g. cathodes with PN junction layers

Definitions

  • the present invention relates to an electron emitting semiconductor device.
  • an electron emitting part is constructed by forming a P-semiconductor layer and an N-semiconductor layer on a semiconductor substrate and reducing the work function of the surface of said N-semiconductor layer by depositing cesium or the like, and an inverse bias voltage is applied across the diode composed of said P- and N-semiconductor layers to induce avalanche amplification, whereby electrons are rendered "hot" and emitted from the electron emitting part in a direction perpendicular to the surface of the semiconductor substrate.
  • the N-semiconductor layer has to be formed extremely thin (200 ⁇ or less), but formation of such extremely thin N-semiconductor layer with sufficient uniformity and low defect rate is difficult, so that stable preparation of the device is therefore difficult.
  • the object of the present invention is to provide an electron emitting semiconductor device not associated with the drawbacks of the prior technology and capable of uniform electron emission over a wide area of arbitrary shape.
  • an electron emitting semiconductor device comprising a P-semiconductive layer formed on a semiconductive substrate; a Shottky barrier electrode formed on said P-semiconductor layer; plurality P+-area units formed under said Shottky barrier electrode; and an N+-area formed in the vicinity of said P+-area units.
  • the electron emitting semiconductor device of the present invention in which a Shottky electrode for a P-semiconductor layer is composed of an area doped with a material for reducing the work function of the surface of the electron emitting part (said material being hereinafter called work function reducing material), can form the electron emitting part in the direction of cross section of the sub­strate, and can also have plural electron emitting parts of arbitrary shapes in a single device.
  • the device of the present invention does not require an ultra high vacuum for stable operation, does not show strong dependence of service life and efficiency on the level of vacuum, and can even by exposed to the air.
  • Conventional electron emitting semiconductor devices show a large energy loss in the N-semiconductor layer because of the use of PN junction, so that the material of an extremely low work function has to be used. In practice, therefore, cesium alone has been used for this purpose.
  • the device of the present invention shows a smaller energy loss than in the conventional devices because of the use of a Shottky junction, so that the usable work function reducing materials include metals of groups IA, IIA and IIIA of the periodic table and of lanthanoid, and silicides, borides and carbides of such metals. More specific examples of said material include TiC, ZrC, HfC, LaB6, SmB6, GdB6, WSi2, TiSi2, ZrSi2 and GdSi2.
  • the electrons which have acquired high energy by avananche amplifica­tion need not go through the N-semiconductor layer for reaching the surface of the electron emitting part. Consequently the device of the present invention is not associated with the difficulty in manufacture such as the necessity of forming an extremely thin N-semiconductor layer, for example 200 ⁇ or less, and can therefore be manufactured in stable manner.
  • Fig. 1 is a schematic view of an example of the electron emitting semiconductor device of the present invention, showing the working principle thereof.
  • a semiconductive substrate 11 there are shown a semiconductive substrate 11; a depletion layer area 12; an n+ area 13; a p-semiconductor layer 14; a p+ area unit 15; a Shottky electrode 16; an n-ohmic electrode 18; and p-ohmic electrode.
  • the semiconductor material to be employed in the electron emitting device of the present invention can for example be Si, Ge, GaAs, GaP, AlAs, GaAsP, AlGaAs, SiC or BP, but any material that can form p-semiconductor can be used for this purpose, and particularly preferred is a material of indirect transition type with a large band gap.
  • Fig. 2 shows the energy bands in the vicinity of the surface of the electron emitting semiconductor device of the present invention.
  • the bottom Ec of the conduction band of the p-semi­conductor assumes an energy level higher than the vacuum level E vac of the Shottky electrode. Electrons generated by the avalanche amplification acquire an energy higher than the lattice temperature by an electric field in the depletion layer generated at the inter­face of the semiconductor and the metal electrode, and are injected into the Shottky electrode consisting of the work function reducing material.
  • the electron emitting semiconductor device of the present invention because of the presence of an N+ area in the vicinity of the interface of the work function reducing material in the P-semiconductor substrate, there is generated a depletion layer at the P-N+ interface. Consequently the electrons injected from the P+-layer into the P-layer are restricted in their moving path by said depletion layer at the P-N+ interface and are concentrated in a p+-area unit provided in the electron emitting part, whereby the current density can be easily increased.
  • the P+-area unit and the N+-area constituting the electron emitting part can be formed for example by ion implantation from the surface of the semi­conductor substrate in the device manufacturing process, there can be formed plural electron emitting parts of arbitrary shapes, at arbitrary positions on a same plane of a substrate.
  • the electron emitting part can be constructed with such successively deposited layer. It is therefore possible to form plural electron emitting parts in a direction perpendicular to the surface of the substrate.
  • the plural P+-area units may be arbitrarily positioned in the P-semiconductor layer, so that an electron beam of an arbitrary shape can be obtained.
  • Fig. 3A is a plan view and Fig. 3B is a cross-sectional view along a line A - A in Fig. 3A, both schematically showing an electron emitting GaAs semiconductor device constituting an embodiment of the present invention, wherein shown are a P+-Si substrate 101; a P ⁇ -layer 102; an annular N+-area 103; a point-shaped P+-area unit 104; an insulating film 105; ohmic electrodes 106, 107; and a Shottky electrode 108.
  • the application of an inverse bias voltage to the Shottky barrier diode 108 induced avalanche amplification at the interface between the Shottky electrode 108 and the point-shaped P+-area 104, whereby electrons of high energy were emitted from the GaSi surface.
  • the presence of the P+-area unit for concentrating the electric field and limiting the electron emitting part limits the point of electron emission, so that the distribution of electron emission in a device can be arbitrarily designed by the arrange­ment of said point-shaped P-area and the size of the P+-area unit.
  • the electron emitting device of the present invention easily allows minituarization or integration of multiple devices because the conven­tional semiconductor process can be utilized for the preparation.
  • Fig. 4A is a plan view
  • Fig. 4B is a cross-sectional view along a line A - A in Fig. 4A, both showing an electron emitting GaAs semiconductor device constituting a second embodiment of the present invention, wherein shown are a P+-Si substrate 401; a P ⁇ -layer 402; an annular N+-area 403; a point-shaped P+-area unit 404; an insulating film 405; ohmic electrodes 406, 407; and a Shottky electrode 408.
  • the electron emitting semiconductor device prepared in this manner was placed in a vacuum chamber maintained at 2 x 10 ⁇ 7 Torr, and was given an inverse bias voltage of 7 V, whereupon electron emission of about 1 nA was observed.
  • Fig. 5 is a plan view
  • Fig. 6 is a cross-sectional view along a line B - B in Fig. 5, both showing an electron emitting semiconductor device constituitng a third embodiment of the present invention.
  • the present embodiment has a line-shaped P+-area unit 505 for concentrating the electric field and limiting the electron emitting part as shown in Fig. 5, so that the electron emission can be obtained continuously over a wide area. Consequently it can be utilized as the electron source for flat panel displays or other display devices in which a linear cathode has been employed.
  • the electron emitting semiconductor device of the present embodiment can be made as a large device or in a large area, because it is a silicon device utilizing the conventional semiconductor process.
  • Fig. 7 is a schematic cross-sectional view of a part of the electron emitting semiconductor device of the present embodiment
  • Fig. 8 is a schematic plan view thereof.
  • the electron emitting semiconductor device thus completed was placed in a vacuum container maintained at 1 x 10 ⁇ 6 Torr, and a fluorescent plate was placed at a distance of 2 mm. By the electron emission from the device, there were observed luminous points corresponding to seven segments of said device. The electron emission was obtained only from segments in which the Shottky electrode was given a positive voltage, so that the display of numerals was possible by the combinations of seven segments.
  • the electron emitting device of the present invention is capable of arbitrarily limiting the electron emitting part, and simultaneously forming plural electron emitting parts on a same substrate.
  • the electron emitting device of the present invention is capable of electron emission in a direction perpendicualr to the cross section of the substrate, and is also capable of electron emissions in plural independent directions by forming the electron emitting cross sections in plural directions.
  • said device can be easily applied for example to a display, since the shape of the electron emitting part can be controlled by the P+-layer embedded in the P-layer.
  • An electron emitting semiconductor device comprises a P-semiconductor layer formed on a semi­conductive substrate; a Shottky barrier electrode formed on the P-semiconductor layer; plural P+-area units positioned under and facing to the Shottky barrier electrode; and an N+-area in the vicinity of said P+-area units.

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  • Cold Cathode And The Manufacture (AREA)
EP19900117200 1989-09-07 1990-09-06 Elektronenemittierende Halbleitervorrichtung Expired - Lifetime EP0416626B1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP233945/89 1989-09-07
JP23394589A JP2820450B2 (ja) 1989-09-07 1989-09-07 半導体電子放出素子
JP1233943A JPH0395825A (ja) 1989-09-07 1989-09-07 半導体電子放出素子
JP233943/89 1989-09-07
JP221713/90 1990-08-22
JP2221713A JPH04102373A (ja) 1990-08-22 1990-08-22 半導体電子放出素子

Publications (3)

Publication Number Publication Date
EP0416626A2 true EP0416626A2 (de) 1991-03-13
EP0416626A3 EP0416626A3 (en) 1991-05-29
EP0416626B1 EP0416626B1 (de) 1994-06-01

Family

ID=27330576

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900117200 Expired - Lifetime EP0416626B1 (de) 1989-09-07 1990-09-06 Elektronenemittierende Halbleitervorrichtung

Country Status (2)

Country Link
EP (1) EP0416626B1 (de)
DE (1) DE69009357T2 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0481419A2 (de) * 1990-10-13 1992-04-22 Canon Kabushiki Kaisha Halbleiter-Elektronenemittierendes Element
WO2021233501A3 (de) * 2020-05-18 2022-01-13 Dbt Gmbh Elektronenemitterstruktur, vorrichtungen mit dieser elektronenemitterstruktur und verfahren zum erzeugen von freien elektronen

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4766340A (en) * 1984-02-01 1988-08-23 Mast Karel D V D Semiconductor device having a cold cathode
EP0331373A2 (de) * 1988-02-27 1989-09-06 Canon Kabushiki Kaisha Elektronenemittierende Halbleitervorrichtung

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4766340A (en) * 1984-02-01 1988-08-23 Mast Karel D V D Semiconductor device having a cold cathode
EP0331373A2 (de) * 1988-02-27 1989-09-06 Canon Kabushiki Kaisha Elektronenemittierende Halbleitervorrichtung

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0481419A2 (de) * 1990-10-13 1992-04-22 Canon Kabushiki Kaisha Halbleiter-Elektronenemittierendes Element
EP0481419A3 (en) * 1990-10-13 1992-05-13 Canon Kabushiki Kaisha Semiconductor electron emission element
US5414272A (en) * 1990-10-13 1995-05-09 Canon Kabushiki Kaisha Semiconductor electron emission element
WO2021233501A3 (de) * 2020-05-18 2022-01-13 Dbt Gmbh Elektronenemitterstruktur, vorrichtungen mit dieser elektronenemitterstruktur und verfahren zum erzeugen von freien elektronen

Also Published As

Publication number Publication date
DE69009357T2 (de) 1994-10-06
EP0416626A3 (en) 1991-05-29
DE69009357D1 (de) 1994-07-07
EP0416626B1 (de) 1994-06-01

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