JPS6187381A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve resolution, and to miniaturize a semiconductor device and enhance the degree of integration thereof by arranging semiconductor light- emitting elements onto an Si single crystal substrate in a monolithic manner. CONSTITUTION:N type GaP layers 2, 5 and non-doped GaP single crystals are grown on an N type Si single crystal substrate 1 in succession, and zinc and oxygen are ion-implanted to a layer 3 and zinc to a layer 6 respectively, thus forming selectively doped P type GaP layers 3, 6. The unnecessary GaP films are removed, and striped layers are shaped. An N type zinc sulfide layer 8 and a P type zinc sulfide layer 9 are formed successively onto the Si substrate, and transparent conductive films, 4, 7, 10 are shaped so as to take an ohmic contact from the layers 3, 6 and 9. The layers 2, 3, 4 represent a GaP P-N junction light-emitting diode and function as a red illuminant, and the layers 5, 6, 7 represent a GaP P-N junction light-emitting diode and serves as a green illuminant. The layers 8, 9, 10 represent a zinc sulfide P-N junction light-emitting diode and function as a blue illuminant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a semiconductor device, and particularly to a semiconductor device having a visible region light emitting function. Furthermore, the present invention relates to a semiconductor device having an image display function using red, green and blue light emitting bodies as pixels.

[Prior art]

BACKGROUND OF THE INVENTION As society becomes more information-oriented with the recent development of electronics technology, information is being actively exchanged between information-related terminals such as businesses and individuals. Under these circumstances, emphasis has been placed on the performance and functionality of terminal devices that receive visual information with high information density, ie, image displays. In general, the performances required of displays for displaying images and text include high resolution, high contrast, high brightness, wide viewing angle, full color, and high fidelity. In terms of functionality, there are demands for hand-held devices, large-screen devices, thin devices, etc. In order to meet these demands, high-performance ○RT,
Pocket-sized LCD color TV, small screen thin IT
J displays, plasma displays, etc. have been commercialized and occupy much of the market.

Although CRTs fully meet the above-mentioned performance requirements, due to their mechanical limitations, they must be made smaller, lighter, and consume less power.
It is not suitable for use as a thin handheld type. In contrast to CRT, liquid crystal displays and KL displays satisfy the above-mentioned functional aspects. However, since the liquid crystal display is a light-receiving display device, it has low contrast and brightness, and due to its characteristics, it has performance disadvantages such as a narrow viewing angle. Further, EL displays and plasma displays have drawbacks such as high driving voltage, difficulty in producing gradation, and difficulty in producing full color.

In the future information society, displays with sufficient performance as described above will be essential, and must also be accompanied by flexibility for multi-functionality. One such display that has been proposed is a light emitting diode array that is self-luminous, full color, and easy to make into a sub screen.Currently, light emitting diodes are made in the three primary colors of red, green, and blue, and are used for display purposes. It is commercially available.

By arranging these three primary color light emitting diodes in a matrix on a plane, and selecting and lighting up the light emitting diodes at appropriate positions, any image can be displayed. Since the pixel elements of this type of display self-emit light, they can produce contrast and brightness comparable to that of a CRT, and by increasing the number of light-emitting diodes, the resolution can be increased and the performance of the display can be improved. Moreover, it is easy to flatten.

However, existing light-emitting diode arrays have a hybrid configuration in which red, green, and blue light-emitting elements are arranged on each chip, which poses problems such as low integration, difficulty in miniaturization, and poor yields. An object of the present invention is to overcome the problems of light emitting diode arrays and provide a highly integrated self-luminous image display with high resolution and easy miniaturization.

〔overview〕

A potassium phosphide epitaxial thin film that emits red light, a gallium phosphide epitaxial thin film that emits green light, and a zinc sulfide epitaxial thin film that emits blue light are grown on silicon single crystal substrates. A luminescent material that emits blue light is monolithically formed in a matrix. Each of the red, green and blue light emitters can be an individual pixel, resulting in an image display with multicolor image display capability. Active electronic circuits for driving each pixel can also be formed on the silicon substrate.

〔Example〕

The crystal structure is very similar to silicon single crystal, gallium phosphide single crystal, and zinc sulfide single crystal. Each single crystal structure has a diamond structure for silicon, and a zinc blend structure for gallium phosphide and zinc sulfide (β-ZnS).The lattice constants of these crystals are 5.431 A for silicon,
Gallium phosphide is 5,4495 A, zinc sulfide is 5.
4095 A, and the difference in lattice constant between these three types of single crystals is only less than 1%, resulting in good lattice matching. Therefore, it is possible to heteroepitaxially grow a gallium phosphide single crystal or a zinc sulfide single crystal on a silicon single crystal substrate while minimizing the occurrence of defects such as dislocations. In addition, good lattice matching can be achieved between gallium phosphide single crystals and zinc sulfide single crystals, so for example, if a gallium phosphide single crystal is grown on a silicon single crystal substrate, then sulfide O-gallium phosphide single crystal, which allows the formation of a heteroepitaxial film with a layered structure by growing a zinc single crystal, is an indirect transition type semiconductor with a band gap energy of 2.25 eV at room temperature. However, even though it is an indirect transition type, it is possible to create a red light emitting body such as a pn junction diode with a peak emission wavelength of about 700nrn by appropriately doping, for example, zinc or oxygen as an acceptor in the P type head region. If a certain gallium phosphide single crystal is doped with nitrogen (N), the electronic transition energy becomes closer to the band gap energy. As a result, the emission peak wavelength was 560
A green light emitting body such as a pn junction diode of about nrn can be formed. Furthermore, by introducing other impurities that can act as acceptors or donors, it is possible to create light-emitting diodes that emit various types of light from red to green. By introducing impurities into this zinc sulfide and creating an appropriate level in the forbidden band, the wavelength can be increased to 480?
A blue light emitter of about Lrn can be obtained.

By forming these red, green, and blue light emitters monolithically on a silicon substrate and making the three-color light emitters emit light with appropriate brightness, it is possible to obtain a light emitter that covers all arbitrary colors in the visible range. Figure 1 shows an embodiment of the present invention. Figures (α) and (6) in Figure 1 represent the aα' and bb' cross sections shown in Figure (C), respectively. In FIG. 1, 1 is a silicon single crystal substrate; 02 and 5 are sulfur-doped gallium phosphide (n-G (IF:S)) layers epitaxially grown on the surface of the silicon substrate by MoCvD; 3 and 6 are sulfur-doped gallium phosphide (n-G (IF:S)) layers. After continuously growing a non-doped gallium phosphide single crystal on the surface of the n-GaP:S layer by MOCVD, zinc and oxygen were added to the layer shown in 3, and zinc was added to the layer shown in 6. This is a p-type gallium phosphide layer selectively doped by a suitable calm ion implantation method.After the formation of these gallium phosphide layers is completed, unnecessary gallium phosphide films are removed by etching to form a striped layer. 8 is an outer zinc sulfide epitaxial layer grown on a silicon substrate by the MOCVD method, 9 is a p-type zinc sulfide epitaxial layer grown continuously on the outer zinc sulfide. 4, 7 and 10 are 3, respectively. , 6 and 9
This is a transparent conductive film formed so that ohmic contact can be made from the pq gallium phosphide and p-type zinc sulfide layers shown in FIG.

In order to make ohmic contact, for example, zinc, gold or
After depositing nickel by sputtering or vapor deposition and interfering at high temperature, T.

(Indium Nine Oxide) A transparent film or the like may be formed.

In FIG. 1, the layers designated 2, 5 and 4 are gallium phosphide p-n junction light emitting diodes, which are red light emitters. The layers designated 5, 6 and 7 are gallium phosphide p-n
It is a junction light emitting diode and emits green light.

Furthermore, the layers designated 8, 9 and 10 are zinc sulfide p −
It is an n-junction light emitting diode and is a blue light emitter. ・11 is the ohmic contact layer of the silicon substrate 0 Figure 2 shows the energy level diagram of the red, green and blue light emitting diodes shown in Figure 1 and the silicon substrate. show.

(a) The figure shows a gallium phosphide red light emitting diode, (b)
The figure shows a gallium phosphide green light emitting diode, and (, +
) The figure shows the energy level diagram of a zinc sulfide blue light emitting diode. ◇As shown in Figure 1, red, green and blue light emitters are formed on the same silicon substrate, the silicon substrate is grounded, By applying an appropriate potential to each of the conductive layers shown in , 7 and 10 and applying an appropriate bias to each candle light body, red, green and blue colors are simultaneously emitted, and as a mixture of these colors, light of any color can be obtained. . Among the six types of luminescent materials shown in Figure 1, the green luminescent material is nitrogen-doped P-type gallium phosphide (Tl-G (I).
F:N) and sulfur-doped external gallium phosphide (n-G
A Pn junction light emitting diode configured with aP:S) may also be used. In addition, instead of a zinc sulfide p% junction diode, we have developed an M-S (Metal-S) in which an insulating film is formed on the n-type zinc sulfide surface and a conductive film is formed on the surface.
-Semiconductor) structure may be used.

In addition to the aforementioned zinc, oxygen, and sulfur, cadmium may be used to make gallium phosphide p-type, and selenium, tellurium, etc. may be used to make gallium phosphide n-type. Also, as a single crystal film growth technology, MOC! In addition to the VD method, there are other methods such as the MBE method.

Other embodiments are shown in FIGS. 3 to 5. In these embodiments, the method of manufacturing each epitaxial layer and the emitter is basically the same as in the embodiment described in FIG.

FIG. 3 shows an embodiment of an image display body in which a large number of the three types of light emitters shown in FIG. 1 are formed on a silicon substrate.

Figures (α) and (6) in FIG. 3 respectively represent the C O' and d d' cross sections shown in Figure (c). K
', In Figure 5, 12 is a p-type silicon substrate, 13 is a p-type silicon substrate, and 13 is a p-type silicon substrate.
A plurality of n-type trench conductive layers are formed in parallel at certain intervals on the surface of a silicon substrate.

14 to 22 are the same as the components 2 to 10 shown in FIG. 22 constitutes a blue light emitting diode. Here, these red, green and blue light-emitting layers are formed on a p-type silicon substrate as shown in 13.
It is characterized by the fact that it is elongated perpendicular to the length direction of the shape-groove electrode layer, and six types of light-emitting layers are alternately formed in a parallel strip shape. Electrons are injected into the n-type layer of each light emitting diode primarily from the n-type silicon conductive layer on the substrate. Therefore, when the n-type silicon conductive layer is grounded and a positive voltage is applied to the conductive layer on the surface of each light-emitting layer, light emission occurs only at the intersections of the n-type silicon conductive II layer and the striped light-emitting layer. Therefore, the light emitting diodes can be addressed in a matrix. By arbitrarily selecting red, 1 ml, and blue light emitting diodes formed in a matrix and causing them to emit light, it is possible to display an image in any desired shape and color.

FIG. 4 shows another image display structure. In FIG. 4, 23 is a p-type silicon single crystal substrate, and 24 is a plurality of n-type groove conductor layers formed in parallel at intervals on the p-type silicon substrate. 25 is an n-type gallium phosphide single crystal layer formed only on the n-type conductive layer 24. Reference numeral 26 denotes a p-type gallium phosphide layer which is elongated and perpendicular to the length direction of the n-type gallium phosphide single crystal layer and is formed on the silicon substrate and the surface of the n-type gallium phosphide layer. It is a transparent conductive layer that can make ohmink contact with p-type gallium phosphide. The gallium phosphide p-n junction diodes 25 and 26 emit red light. 28 is p-type gallium phosphide formed in parallel with the p-type gallium phosphide of 26, 29 is a transparent conductive layer with which ohmic contact can be made, and the n-type gallium phosphide of 25 and the p-type gallium phosphide of 28 are formed. A p-n junction light emitting diode is formed to generate green light.

50 is an n-type zinc sulfide single crystal, 31 is a p-type zinc sulfide single crystal, and 62 is a transparent conductive layer that can make ohmic contact with the p-type zinc sulfide. Zinc sulfide p shown in 30 and 31
-The n-junction diode becomes a blue light-emitting diode◇Carriers are injected into this blue light-emitting diode from the transparent conductive layer with 32 holes and the n-type gallium phosphide layer with 25 electrons, respectively. The operation for displaying an image is the same as the method described in the explanation of FIG. By creating the structure shown in Figure 4, it is possible to cover the entire surface of the silicon substrate with gallium phosphide, which prevents oxidation of silicon that occurs during the process, improving device characteristics, reliability, and yield. It has the characteristic of being

FIG. 5 shows an embodiment of a light emitting body in which active electronic elements for driving light emitting elements are built on the surface of a silicon substrate. FIG. 5(α) shows a cross section of the silicon substrate. 33 is a p-type silicon substrate, 35 is an n-type silicon epitaxial layer,
Reference numeral 34 is a p+ type diffusion layer for isolation, which electrically isolates adjacent electronic elements. 35 is an n-type collector layer, 36 is a p+ type base layer, 37 is an n-type emitter layer,
Each of the layers 65 to 37 forms an npn bipolar transistor. 39 and 40 indicate n-type and p-type gallium phosphide light-emitting diodes (or they could also be n-type and p-type zinc sulfide light-emitting diodes) epitaxially grown on the surface of the n-type collector region of the silicon bipolar transistor.

41 is an insulating film for protecting the silicon substrate surface and the cross section of the light emitting diode layer. 42 is a conductive film for making ohmic contact from the p shadow region of the light emitting diode, 46 is a base electrode of the bipolar transistor, and 44 is an emitter electrode of the bipolar transistor. In a device with this structure, after grounding the emitter and applying a sufficient potential to the p-type side electrode 42 of the light-emitting diode to cause it to emit light, a current sufficient to turn on the transistor is caused to flow through the pace electrode 43. , a forward current flows through the light emitting diode and it emits light.

At this time, since it is possible to control the current flowing to the collector with the base current, the amount of light emission can also be controlled.

Furthermore, by arranging the light emitting diodes with drive elements shown in FIG. 5(,) as shown in FIG. 5(6), a light emitting diode matrix for image display can be formed. 45 is the bipolar transistor 146 on the silicon substrate mentioned above, which is a light emitting diode, and 47 is a transistor that turns ON-OFF, or is it a light emitting diode? ! A base signal line 48 is used to control the T1 current, and 48 is a drive line that applies a potential to the light emitting diode and allows current to flow in. By appropriately selecting the base signal line 047 and the drive line 48, and controlling the current, it can be moved to any position. The light emitting diode can be made to shine at any desired brightness.

By arranging red, green, and blue light-emitting layers alternately in a striped pattern as shown in FIGS. 3 and 4, multi-color light emitting diode layers can be realized. In this example, the active element formed on the silicon substrate is a bipolar transistor, but in addition to this, M-SFI! :T, S
You may also use T. Further, a drive circuit for selecting and operating signal lines and drive lines may be formed on the silicon substrate around the light emitting diode matrix.

As another embodiment, any of the systems shown in FIG. 6, FIG. 4, or FIG. It is possible to create an element that can emit white light as a mixture of these colors. This is for example a facsimile or an energy sensor.

O can be used as a light source for area sensors, etc. [Effects] By monolithically arranging semiconductor light emitting elements on the same substrate, it is possible to achieve higher density than conventional light emitting diode arrays, resulting in high resolution in a small area. An image display body was obtained. Furthermore, since it is self-luminous despite having a planar structure, it was able to achieve high brightness and high contrast while maintaining the functionality of flatness and light weight, which are characteristic of conventional liquid crystal displays.

In addition, by selecting a silicon single crystal substrate as the base substrate for forming a light emitting element, a compound semiconductor single crystal having a light emitting function can be formed on its surface relatively easily.
We were able to create a highly efficient light emitting device called a p-n junction diode. Nricon's substrate technology has been fully established through the development of LSI, etc., and defect-free, large-area silicon single crystal substrates can be obtained at low cost, making it possible to produce highly reliable and inexpensive light emitters with a high yield. Another feature is that high-performance electronic circuits can be incorporated using silicon brainer technology, which has been established for LSI and other technologies.

[Brief explanation of the drawing]

1 to 5 show embodiments of the present invention,
Figures 1 (α) to (c) and Figures 2 (α) to (c) are basic explanatory diagrams for forming red, green, and blue light emitting elements on a silicon substrate in the present invention. Figures fa) to (c)
and FIG. 4(α) to (e) show the light emitting elements (IJ).
An example of arranging them in a box shape, and Fig. 5 (α)
, (b+ is an explanatory diagram of a light emitting body in which an active electronic circuit for driving a light emitting element is formed on a silicon substrate. 1... N-type silicon single crystal substrate 2, 14... N-type gallium phosphide epitaxial layer 3.15...p-type gallium phosphide epitaxial layer 4.7, 16.19...transparent conductive layer 5.17...n-type gallium phosphide epitaxial layer 6.18...p-type gallium phosphide Epitaxial layer 8.20...N-type zinc sulfide 9.21...P-type zinc sulfide 10.22...Transparent conductive layer 11...Silicon substrate contact 1MJi12.23
...p-type silicon single crystal substrate 13.24...n-type silicon conductive layer 25...n-type gallium phosphide epitaxial layer 26.
...p-type gallium phosphide epitaxial layer 27.29.
・Transparent conductive layer 28 ・P-type gallium phosphide epitaxial layer 30 ・
... N-type zinc sulfide 31 ... P-type zinc sulfide 32 ... Transparent conductive layer 36 ... P-type silicon single crystal substrate 34 ... P swelling diffusion layer 35 ... N-type silicon epitaxial layer, collector region 36 . . . P-type base layer 37 . ... Base electrode 44 ... Emitter electrode 45 ... Driving bipolar transistor 46 ... Light emitting diode 47 ... Base signal line 48 ... Drive line Fig. 3 Fig. 4

Claims (4)

[Claims] (1) At least one type of epitaxial thin film selected from among a gallium phosphide epitaxial thin film that emits red light, a gallium phosphide epitaxial thin film that emits green light, and a zinc sulfide epitaxial thin film that emits blue light is deposited on a silicon single crystal substrate. 1. A semiconductor device characterized in that the semiconductor device is grown by heteroepitaxial growth on the surface of the substrate, or by stacking the epitaxial thin films that emit red, green, and blue light on the surface of a silicon single crystal substrate. (2) A conductive layer of a conductivity type different from that of the substrate is formed on a silicon single crystal substrate, and at least one of the epitaxial thin films that emit red, green, and blue light is formed on the substrate and the conductive layer. 2. The semiconductor device according to claim 1, wherein epitaxial thin films of different types are formed in a stripe shape or matrix shape, and a transparent conductive film is further formed on the outermost surface of the epitaxial thin film. (3) The semiconductor device according to claim 1, wherein the conductive layer on the silicon substrate and the transparent conductive film are used as electrical wiring. (4) The semiconductor device according to claim 1, wherein active electronic circuits for driving red, green, and blue light emitters are formed on a silicon single crystal substrate.