JPS63141235A - Photo-exciting electron emitting element - Google Patents

Abstract

PURPOSE:To form an electron emitting element capable of controlling the emitting electron amount by the light and to enable the integration in a simple structure, by superposing a connection-type photoelectric converting domain and an MIM type electron emitting element domain. CONSTITUTION:A connection-type photoelectric converting domain is formed by superposing an N-type semiconductor domain 3, a P-type semiconductor domain 4, and a conductive domain 5, partially over a transparent electrode 2 of a light-permeable base plate 1. At both sides of an insulating domain 6, the domain 5 and a metallic layer 7 are positioned, and an MIM type electron emitting element domain is formed to emit electrons by applying a necessary voltage between the layer 7 and the domain 5, emitting from a recess 9 with a work function reducing material domain 8 at the surface of the layer 7. The electrons generated by the light permeated through the plate 1 are implanted to the domain 5, and the electron amount emitted from the recess 9 is controlled. Since the domain 5 is the common part for the two domains, the structure is simple, and since it is a superposed structure, the integration work is easy.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a photo-excited electron-emitting device, and in particular to a device that photoelectrically converts incident light using a junction-type photoelectric conversion region and conducts the generated electrons.
The present invention relates to a photoexcited electron-emitting device that emits electrons by injecting electrons into an electron-emitting device (hereinafter referred to as HIM-type electron-emitting device) region composed of an rrL region and a metal layer provided through an insulating region.

[Prior Art] FIG. 3 is a schematic diagram showing the general configuration of a 1M type main electron emitting device.

As shown in the figure, the MIM type electron-emitting device is made of metal M
The structure has a structure in which a thin metal M2 is laminated on top of the metal M2 with a thin insulating layer (2) interposed therebetween. And gold 1i! The work function φ of M2, by applying a larger voltage V between the metals Ml and M2, the insulating layer! Of the electrons that have tunneled through, those with energy greater than the vacuum level are emitted from the surface of the metal M2.

In order to obtain high electron emission efficiency in such a device, it is desirable to form the insulating layer I as thin as possible within a range that does not cause dielectric breakdown, and within a range that allows sufficient current to flow through the metal M2.

FIG. 4 is a schematic cross-sectional view of a conventional 1M type main electron-emitting device. As shown in the figure, in the electron emission part W, the metal M2 is formed thinly to improve electron emission efficiency.

[Object of the Invention] The present invention aims to provide an electron-emitting device which can control the amount of electrons emitted from the Ml-l-electron-emitting device by light, can be integrated, and has a simple configuration. purpose.

[Summary of the Invention] The photoexcited electron-emitting device of the present invention includes a transparent electrode provided on a light-transmitting substrate, and a semiconductor region of one conductivity type, a semiconductor region of the opposite conductivity type, and a conductive region laminated in this order on the transparent electrode. a junction-type photoelectric conversion region provided on the surface of the junction-type photoelectric conversion region; an insulating region provided on the surface of the junction-type photoelectric conversion region; and a recess provided on the conductive region through the insulating region and on the conductive region. The metal layer is characterized in that it has a metal layer.

[Function] The photoexcited electron-emitting device of the present invention includes a junction type photoelectric conversion region formed by laminating a semiconductor region of one conductivity type, a semiconductor region of the opposite conductivity type, and a conductive region on a transparent electrode, and the conductive region. A MIMy1 electron-emitting device region composed of an insulating region and a metal layer is formed and integrated on a light-transmissive substrate, and the electrode of the junction-type photoelectric conversion region and the MrM-type electron-emitting device region are shared. In addition, an insulating region is provided to provide electrical insulation, resulting in a simple structure that can be integrated. Further, the junction type photoconversion region is provided only in the area under the concave portion of the metal layer, which is the electron emitting portion of the MIM type electron emitting device, so that electrons can be emitted efficiently.

Note that if a work function decreasing material region is formed in the recess,
Electrons can be emitted from the metal layer with more constant energy, and electron emission efficiency can be further improved.

[Example] Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 1(a) is a schematic partial cross-sectional view showing the basic structure of the photoexcited electron-emitting device of the present invention, and FIG. 1(b) is a cross-sectional view of a recessed portion of a metal layer.

In FIG. 1(a), a transparent electrode 2 made of ITO or the like is formed on a light-transmissive substrate 1 made of glass or the like. An N-type semiconductor region 3 is partially formed on this transparent electrode 2, a P-type semiconductor region 4 is formed on this N-type semiconductor region 3, and a conductive region 5 is further formed. Note that the conductive region 5 is made of a metal such as An or a semiconductor such as 2Si. Transparent electrode 2.
The N-type semiconductor region 3, the P-type semiconductor region 4, and the conductive region 5 constitute a junction type photoelectric conversion region.

An insulating region 6 is provided on the conductive region 5 and on the side of the junction type photoelectric conversion region, and the conductive region 5 and the P-type semiconductor region 4
．． When using St as the N-type semiconductor region 3, Sjng
is preferably used. A! L, ^
A metal layer 7 such as U or PT is provided, and a recess 9 is formed in the region of the metal N7 above the junction type photoelectric conversion region. A work function lowering material region 8 is formed in this recess 9, and the work function lowering material used is an alkali metal, an alkaline earth metal, etc., and Cs, for example, is preferably used. Conductive region5. Insulating region 6 and metal layer 7 are 11111
type electron-emitting device.

In this embodiment, the conductive region 5 is one electrode of the junction type photoelectric conversion region and also serves as the conductive layer of the 111111 type electron-emitting device, and is shared, resulting in a simple structure. The insulating region 6 serves as an insulating layer of the MIM type electron-emitting device, and serves as an insulating region that insulates the side surface of the junction type photoelectric conversion region from other regions, thereby preventing characteristic deterioration due to leakage or the like. Furthermore, in this embodiment, as mentioned above,
Junction type photoelectric conversion region that performs photoelectric conversion and M that performs electron emission
Since the IM type electron emission region is stacked and integrated, integration is possible, and since the junction type photoelectric conversion region is formed only in the region under the concave part where electrons are emitted,
It is possible to efficiently emit electrons. Note that by providing the work function lowering material region 8 in the recess 9, an effect of 0 or more that further increases the electron emission efficiency results in the integration of a photoexcited electron emitting device having a large number of photoexcited electron emission sources such as an imaging device. This makes it possible to manufacture the product in a variety of formats.

In this embodiment with such a structure, when a voltage V is applied between the conductive region 5 and the metal layer 7 and light is irradiated to the junction type photoelectric conversion region through the light-transmitting substrate 1, the P-type semiconductor region 4 and A photovoltaic force is generated between the N-type semiconductor region 3 and the Mi
Electrons are injected into the conductive region 5 of the ll-type electron emission electron emitting device, and the electrons tunneled through the insulating region 6 are emitted from the recess 9 of the metal layer 7 where the work function has been lowered by the work function lowering material region 8. Since electron emission is also possible at low energy, efficient electron emission is possible.

FIG. 2 is a schematic diagram showing an embodiment of the photoexcited electron-emitting device of the present invention.

As shown in the figure, a large number of recesses 9 are provided in the metal layer 7, each of which is provided with an l1llllfi electron emitting region and a junction type electron emitting region. Note that the interval between the respective recesses 9 can be set on the order of 1 m.

[Effects of the Invention] As explained in detail above, the photoexcited electron-emitting device of the present invention integrates the junction-type photoelectric conversion region and the 1-type electron-emitting device region, and the electrode of the junction-type photoelectric conversion region and Myanmar I
The electrode of the M-type electron-emitting device region is shared by a conductive region to form the same electrode, and an insulating region is provided to provide electrical insulation, thereby making it possible to have a simple structure that can be integrated. Further, the junction type photoelectric conversion region is provided only in the region under the concave portion of the metal layer, which is the emission portion of the MIM type electron-emitting device.

Electron emission can be performed efficiently. As a result, it becomes possible to integrate and manufacture a photoexcited electron-emitting device having a large number of photoexcited electron-emitting sources, such as an image sensor.

S, if a work function decreasing material region is formed in the recess,
Electrons can be emitted from the metal layer with lower energy, and electron emission efficiency can be further improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the basic configuration of the photoexcited electron-emitting device of the present invention. FIG. 2 is a schematic diagram showing an embodiment of the photoexcited electron-emitting device of the present invention. FIG. 3 is a schematic diagram showing the general configuration of an MIM type electron-emitting device. FIG. 4 is a schematic cross-sectional view of a conventional MIM type electron-emitting device. 1...Light-transmitting substrate 2...Transparent electrode 3-N-type semiconductor region 4-P-type semiconductor region 5...Conductive region 6...Insulating region 7...Metal layer 8...Work Function-decreasing material region 9...Concave agent Patent attorney Seki Yamashita Figure 1 (a) (b) Figure 2

Claims (2)

[Claims] (1) a transparent electrode provided on a light-transmitting substrate; a bonded photoelectric conversion region provided on the transparent electrode by sequentially stacking a semiconductor region of one conductivity type, a semiconductor region of the opposite conductivity type, and a conductive region; A photoexcited electron-emitting device having an insulating region provided on the surface of the junction type photoelectric conversion region, and a metal layer provided on the conductive region via the insulating region and having a recessed portion above the conductive region. . (2) The photoexcited electron-emitting device according to claim 1, wherein a work function decreasing material region is formed in the recess.