JPS60170983A - Semiconductor light-emitting device - Google Patents

Abstract

PURPOSE:To attain a high productivity by a method wherein a layer is grown, composed of a compound semiconductor belonging to the II-VI group, upon a substrate belonging to the II-V group available in a large size at a low price. CONSTITUTION:An Al-added n type layer 12 is grown on an n type GaP substrate 11. On the layer 12 grown in this way, a high-resistance layer 12a is created of ZnS due to asymmetric lattice constants along the interface between the layer 12 and substrate 11. A process follows wherein an ohmic electrode 13 is built on a part of the layer 12 and a high-resistance film 14 is formed of undoped ZnS over the upper surface of the layer 12. Then, on the film 14, a Schottky electrode 15 is built for the formation of a planar-type MISLED. When a voltage is applied across the electrodes 15 and 13 on the LED with the negative potential applied to the electrode 13, blue light is generated in the vicinity of the electrode 15. With the light-emitting device using a substrate belonging to the II-V group available in a large size at a low price, a high productivity may be attained.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a semiconductor light emitting device used, for example, as a display light source (LED lamp, LED display confectionery), etc., and particularly relates to a semiconductor light emitting device such as a blue light emitting LED. It is something.

[Technical background of the invention]

For example, as shown in Japanese Patent Publication No. 58-26186, a conventional blue light emitting device is as follows. That is,
In Fig. 1, minority group elements such as A[(fluminilum), I"(indium), or Ga(gallium) are added to Zn8 (zinc sulfide) single crystal 1 in order to improve the luminous efficiency and further lower the resistance. Heat treatment is performed in a Zn solution for the purpose of.

Then, an AJ or In-based ohmic electrode 2 is formed on one surface of this single crystal 1.

Further, a high resistance layer 3 is formed on the opposing surface of the single crystal 1 parallel to the ohmic electrode, and a Schottky electrode 4 made of A'u (gold) or pt (platinum) is further formed on this high resistance layer 3. form.

When electricity is applied between the Schottky electrode 4 and the ohmic electrode 2 of the device thus obtained, the Schottky electrode 4
Blue light emission can be obtained in the vicinity.

Incidentally, as shown in FIG.
Semiconductor) i is made of Zn
This is because a p-type crystal cannot be obtained even when doped with a p-type impurity due to a self-compensation effect in a . . . -■ group semiconductor such as S, and a p-n junction type LFD cannot be obtained.

[Problems with background technology]

By the way, the ZnS single crystal substrate used as the above-mentioned blue light emitting LED (2) ZnS single crystal 1 is usually manufactured by a high pressure melting method, but it is generally difficult to obtain a large single crystal with ■-■ group semiconductors. The diameter of the largest one is about 1.5 m (about 1 m). Therefore, the number of LFDs obtained from one single crystal substrate is small, resulting in poor productivity.

In addition, the ZnS single crystal mentioned above is doped with Al as a blue-emitting dopant, but if it is simply doped with A6, the axial resistance of the single crystal is more than 107Ω・α, and 'L
It cannot be used as an ED substrate. Therefore, in order to lower the resistance of the ZnS single crystal to 10Ω・α or more, it is necessary to heat treat the ZnS single crystal in a Zn (zinc) solution for a certain period of time. It was of low quality.

[Purpose of the invention]

The present invention has been made in view of the above points, and can be manufactured without requiring heat treatment with a Zn solution on a single crystal conductor substrate, and can be mass-produced at a low price without the need to use a Group 2 single crystal substrate. The purpose of the present invention is to provide a semiconductor light emitting device with excellent productivity and high productivity.

[Summary of the invention]

That is, the semiconductor light emitting device according to the present invention includes a semiconductor layer having a growth layer of an n-vt group compound semiconductor on at least the surface thereof, and a first semiconductor layer formed on a partial region of the surface of the growth layer.
The device includes an electrode, and a second electrode provided on the surface of the growth layer at a location separated from the first electrode via a high-resistance film.

[Embodiments of the invention]

Is the drawing below? An embodiment of the present invention will be described by storing heat.

First, in FIG. 2, for example, L E C (Liquid
Encapsulated Czochralskl
) An n-type GaP (100) wafer formed by the method is prepared as a substrate 11.

Next was MOCVD (Metal Organic C
Chemical Vapor Deposition
) method, a growth layer 12 is formed by heteroepitaxially growing n-type ZnS of about 5 μm to which AJ is added as a blue-emitting dopant on the GaP substrate 1 .

The growth of this n-type ZnS is performed, for example, as follows.

The GaP substrate 1 is placed on a silicon carbide susceptor (substrate stand) heated by high frequency or electric furnace, and the substrate temperature is set at around 400°C. Furthermore, organic metals such as Zn, such as DMZ (dimethylzinc), and H! S (hydrogen sulfide) gas and l organometallic as a dopant, e.g. TE.
A() rietheraluminum) is poured onto the substrate 11. The flow rates of these component gases are 10 ee/min for DMZ (organometallic set temperature 0°C), 10 ec/min for TEA (organic metal set temperature 20°C), and Hts (
10% dilution gas with Hs gas) at 30 cc/min.

In the ZnS growth layer 12 formed as above,
Z due to lattice constant mismatch near the interface with the substrate 11
An n5O high resistance layer 12a is formed. The thickness of both paper anti-layers is 0.5 μm or more, and a voltage of 100 V or more is required to cause dielectric breakdown. - The specific resistance of the surface of the growth layer 12 is about 1Ω·α, which is even lower than that of the conventional ZnS substrate with low resistance.

Next, on the surface of the ZnS film formed as described above, an [n-Ga alloy was deposited using a metal mask, etc., and sintering was performed at 370°C to form a film as shown in FIG. An In-Ga ohmic electrode 13 is formed as one electrode on a partial region of the growth/ii J 2.

Thereafter, an undoped ZnS film is formed as a high resistance film 14 on the upper surface of the grown layer 12 by MOCVD, for example.
It is grown to about 00'A.

Thereafter, gold (A
u) Alternatively, a Schottky electrode 15 is formed as the second electrode by vapor deposition of platinum (PT), and a planar type MI
S (MetalInsulator Sem1con
ductor) Obtain LED.

When electricity is passed between the Schottky electrode 15 and the ohmic electrode 13 of such a device with the ohmic electrode 13 as the negative electrode, blue light emission (with a wavelength of about 470 nm) is obtained in the vicinity of the Schottky electrode 15. Here, n-type ZnS
Since the high resistance layer 12h exists at the bottom of the growth layer 12, it is not electrically affected by the Gap substrate 11, and the L
The basic structure of the ED can be considered to be the same as the conventional one shown in Figure M1.

In addition, since the downward light emitted near the Schottky cage pole is absorbed by the qaP substrate 10, the GaP substrate is removed as shown in FIG. 4 to achieve a higher luminous efficiency than that in FIG. 3. You can also get it. .

In the above embodiment, an n-type GaP substrate is used as the substrate 11 and a ZnS't- substrate is used as the growth layer 12. Other materials may be used as long as they are made of a material. For example, GaP and GaAa can be used as the substrate. The growth layer contains Zn as a group Ⅰ element,
Cd.

It is expected that S, Se, and Te will be used as the Group Ⅰ element, but ZnS or Zn5e is currently most desirable.

In addition, methods for heteroepitaxial growth of a growth layer include not only the MOCVD method but also molecular beam epitaxy (MB), which can obtain a growth layer with low resistance through low-temperature crystal growth.
E) law can be adopted.

Furthermore, the high resistance film 14 is not limited to the above-mentioned embodiments, and may be, for example, a ZnjS film formed by vapor deposition of high-purity ZnS powder, a 5i02 film of about 1000A formed by sputtering, or a surface of a ZnS film formed by, for example, H,02 liquid. A film etc. which are oxidized may also be used.

Further, as a dopant for the growth layer 12, for example, Ga, In, etc. may be used in addition to AI, and the ohmic electrode 13 may be used as a dopant.
In can also be used as an electrode material.

In or alloys containing In such as In-Ga, ln-Hg, and metals such as A/ may also be used.

Further, the second electrode formed on the high-resistance film J4 does not necessarily have to be a Schottky electrode, but at present, a Schottky electrode is advantageous in terms of luminous efficiency and the like.

〔Effect of the invention〕

The semiconductor light emitting device according to the present invention as described above provides the following effects.

First, as a board, it has a large area (maximum diameter of about 3 inches).
1- of GaP substrate or GaAs substrate that can obtain
2V&: Because the board is used, L obtained from one board
The number of EDs can be increased, and productivity is higher than conventional ones.

Furthermore, ZnS or Zn5e containing the dopant A7
Since this crystal is formed by epitaxial growth, the q resistivity near the surface of this grown layer can be made extremely small compared to the ZnS single crystal of the conventional device. Therefore, in a semiconductor light-emitting device that uses the surface of a grown layer as a current-conducting path like the device of this embodiment, there is no need to perform a complicated heat treatment to lower the resistance in a ZN solution. Here, GaP substrate or G
When a II-Vl group crystal is grown on an aAs substrate,
A high resistance layer 12a is formed near the interface between the growth layer and the substrate, but by providing the first electrode 13 and the second electrode 15 on the surface side of the growth layer 12, the influence of the high resistance layer 12a and the influence of the substrate can be reduced. influence can be avoided.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional semiconductor light emitting device, FIGS. 2 and 3 are sectional views showing a semiconductor light emitting device according to an embodiment of the present invention along with the manufacturing process, and FIG. 4 is a sectional view showing a semiconductor light emitting device according to an embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 11... Substrate, 12... Growth layer, 12a... High resistance layer, 13... Ohmic electrode (1st electrode), 14...
...High resistance film, 15... Schottky electrode (second electrode). Applicant's agent Patent attorney Suzu Ushiki Hiko No. 1 No. 2; rSa Figure Figure 4

Claims (1)

[Scope of Claims] (1) A semiconductor layer consisting of a grown layer of an It-Vl group compound semiconductor, a first electrode formed on a partial region of the surface of the grown layer, and a first electrode formed on a part of the surface of the grown layer; 1. A semiconductor light emitting device comprising: a second electrode provided at a portion separated from the first electrode via a flat resistive film. (2) The first electrode is an ohmic electrode, and the second electrode is an ohmic electrode.
%ff characterized in that the electric ladder is a Schottky electrode
A semiconductor light emitting device according to claim 1. (3) The semiconductor light emitting device according to claim 1 or 2, wherein the semiconductor layer is a grown layer of n-type Zn8 or n-type Zn8e. Button according to any one of claims 1 to 3, characterized in that the resistance is higher on the back side of the semiconductor layer than on the front side of the semiconductor layer where the first electrode is formed. Semiconductor light emitting device. A semiconductor light emitting device according to claim 1 or 2, characterized in that: (6) The semiconductor light emitting device according to claim 5, wherein the growth layer has a higher resistance on the bottom surface side in contact with the single crystal substrate than on the surface side where the first electrode is formed. . Q) The single crystal substrate is a GAP substrate or a G&A@ substrate, and the growth layer is an n-type ZnS layer or an n-type Zn5e layer.
The semiconductor light emitting device according to claim 6, which is a layer.