JPS63288083A - Semiconductor light-emitting device - Google Patents

Abstract

PURPOSE:To obtain a device, in which electrodes are led out easily and which has excellent characteristics, by forming p-type and n-type conductive regions reaching a first clad layer from the surface of a semiconductor base body and oppositely facing through superlattice structure and the electrodes respectively brought into contact with the p-type and n-type conductive regions on the surface of the base body. CONSTITUTION:A high-resistance Al0.45Ga0.55As clad layer 1', superlattice structure 2, a high-resistance Al0.45Ga0.55As clad layer 1, and an n-type GaAs cap layer 4 are epitaxial-grown onto a semi-insulating GaAs substrate 10 in succession. In the superlattice structure 2, p-type layers 2Bp, in which beryllium (Be) is doped to Al0.3 Ga0.7As layers, and n-type layers 2Bn, in which silicon (Si) is doped to the Al0.3Ga0.7As layers, are shaped alternately as barrier layers, and non-doped GaAs active layers 2A are formed among both layers 2Bp and 2Bn. A p side electrode 9p is disposed onto the p-type conductive region 5p and an n side electrode 9n onto an n-type conductive region 5n. Holes are injected to an active layer 2A through the p-type barrier layer 2Bp from the p-type conductive region 5p and electrons through the n-type barrier layer 2Bn from the n-type conductive region 5n. Accordingly, constraint by the diffusion length of carriers is not conducted, and the range of selection of a distance between the p-type conductive region 5p and the n-type conductive region 5n is increased.

Description

Detailed Description of the Invention (Summary) The present invention relates to a semiconductor light emitting device, in which high resistance cladding layers are formed above and below a superlattice structure in which an active layer is sandwiched between barrier layers alternately doped with acceptor impurities and donor impurities. forming p-type and n-type conductive regions from the surface of the semiconductor substrate that face each other via the superlattice structure and reach the lower cladding layer; By providing electrodes in contact with the respective electrodes, it is possible to easily provide a horizontal semiconductor light emitting device with excellent characteristics and easy electrode extraction.

[Industrial application field]

The present invention relates to a structure of a semiconductor light emitting device, particularly a horizontal semiconductor light emitting device suitable for integration.

Semiconductor light-emitting devices are being improved for the sophistication, advancement, and diversification of optical communications, etc., and in particular, improvements are being made for optoelectronic integrated circuits (ORIC), which monolithically integrate semiconductor light-emitting elements and their modulation circuits, etc. Therefore, there is a need for a horizontal semiconductor light-emitting device that has a brainer shape and can be easily pulled out.

[Conventional technology]

Most of the semiconductor light emitting devices currently used in optical communications etc. are vertical type in which current is passed perpendicular to the surface of the semiconductor substrate, but various horizontal type semiconductor light emitting devices have also been developed. has provided a semiconductor light emitting device as illustrated in FIG. 3 in Japanese Patent Application No. 60-270509.

In this conventional example, high resistance Io, asGao, 5sAsfi21'', multiple quantum well (MQGI) active F!22, high resistance Io, 4S are formed on a semi-insulating GaAs substrate 20.
ca@, ss8 to J? J21 and an n-type GaAs cap layer 24 are epitaxially grown in this order. This MQW
The active layer 22 is made of GaAs WJ with a thickness of 30 mm and a thickness of 120 mm.
Ale, aGao, and hAsN are alternately formed, and the energy band is as shown at the bottom of the conduction band Pc in the lower part of the figure.

An n-type impurity diffusion region 25p and an n-type impurity diffusion region 25n are formed in this semiconductor substrate, and the MQW structure of these regions is disordered to have an averaged composition.
A double heterostructure is formed in the lateral direction of the Q-active layer drive 28. The refractive index of this disordered part is MQW
The average refractive index of the active layer 28 is lower than that of the active layer 28, resulting in a lateral refractive index distribution as shown in (a).

On the other hand, high resistance AI6.4ScaO, 5sAs layer 21.2
1' and the MQW active layer 28 sandwiched therebetween have a refractive index distribution like (bl), and the light generated in the MQ-active FJ2B is confined here.

In this conventional example, holes are injected into the MQ-active layer sdrive 28 from the n-type impurity diffusion region 25p and electrons from the n-type impurity diffusion region 25n.
The 10-active layer sdrive 28 sandwiched between the GaAs layers 21.21° has a total thickness of, for example, 0.1. It is easy to epitaxially grow to a thickness of n or less, and the current is narrowly constricted. Combined with the fact that the active layer has an MQ-structure, the dark value current is reduced and the efficiency is improved.

[Problem that the invention seeks to solve]

The conventional semiconductor laser is of the Brehner type, with both electrodes provided on the surface of the semiconductor substrate, and has excellent characteristics. However, due to its structure, the width of the IW active layer stripe 28 is It must be smaller than the sum of the lengths and approximately 1- or less.

However, with the current manufacturing method, it is extremely difficult to accurately control the distance between the n-type impurity diffusion region 25p and the n-type impurity diffusion region 25n to such a small value, and a solution to this problem is strongly desired. .

[Means for solving problems]

The problem is that the semiconductor substrate includes a first high-resistance cladding layer having a first bandgap, and a second high-resistance cladding layer formed on the first cladding layer and doped with acceptor impurities and donor impurities alternately. a superlattice structure in which an active layer having a third bandgap narrower than the first and second bandgaps is formed between barrier layers having a bandgap of; a second high-resistance cladding layer having a fourth bandgap wider than the bandgap, reaching the first cladding layer from the surface of the semiconductor substrate and opposing n-type and n-type cladding layers via the superlattice structure; Type guide 7r1.
The problem is solved by a semiconductor light-emitting device according to the invention, comprising: a conductive region of the ESp type and an n-type conductive region, respectively, on the surface of the semiconductor body.

[For production]

The semiconductor light emitting device according to the present invention is doped with acceptor impurities and donor impurities alternately, as shown in FIG. 1(a) as a schematic cross-sectional view and as shown in FIG. active J! between barrier F2Bp and 211n!
From the surface of the semiconductor substrate, which has a superlattice structure 2 sandwiching 2A and high-resistance cladding Jil, 1' above and below it, it faces through this superlattice structure 2 and reaches the lower cladding Nl'. P-type and n-type conductive regions 5p and 5n are formed, and electrodes are provided on the surface of the semiconductor substrate in contact with the p-type and n-type conductive regions, respectively.

In this semiconductor light emitting device, holes are transferred from the p-type conductive region 5p to the p-type conductive region 5p.
After passing through the type barrier layer 2Bp, electrons are injected from the n-type conductive region 5n into the active stone 2^ through the n-type barrier WI2811. Therefore, there is no restriction due to the diffusion length of carriers as in the conventional example, and there is no restriction between the p-type conductive region 5p and the n-type conductive region 5p. ¥Off area 5n
Not only does the selectable range of the distance between the two positions increase, but even if manufacturing errors occur, the effects thereof are minor.

Note that p-n junctions occur between the p-type barrier m2Bp and the n-type conductive region 5n and between the n-type barrier Ji2Bn and the p-type I71iI region 5p, but the leakage current in this part can be suppressed due to the built-in potential difference. can.

Furthermore, if the active layer 28 is thin and the superlattice structure 2 constitutes an MQW using this as a well layer, effects such as a reduction in dark value current and an improvement in temperature characteristics due to the MQW structure can be obtained. Note that in the semiconductor light emitting device of the present invention, carriers do not need to tunnel through the barrier layer.

〔Example〕

The present invention will be specifically explained below with reference to an example whose schematic cross-sectional view is shown in FIG.

In this embodiment, a semi-insulating GaAs substrate 10 is formed with a thickness of, for example, lI! m high resistance Ale, asGao, 5sAs cladding stone l°, following superlattice structure 2, thickness e.g. The cap layer 4 is epitaxially grown in sequence.

As shown in FIG. 1, this superlattice structure 2 includes, for example, a 300-layer AI+, 1 Gao, and Js layer doped with beryllium (Be) to a concentration of about IXIO" cm, a p-type layer 2B. Silicon (Si) concentration I
N-type N2Bn doped to about cm-' are alternately used as barrier layers, and a non-doped GaAs active FJ2A with a thickness of, for example, 100 layers is formed between them.

In this example, the semiconductor substrate is etched using a mixed solution of hydrofluoric acid, hydrogen peroxide, and pure water to form two grooves sandwiching a striped mesa region having a width of, for example, 3. For example, 5- is formed to a depth that reaches the lower cladding layer 1'', and on one side, for example, Be is formed at a concentration of lXl0'1 cm.
−” to p-type doped Is, aGao, 6A
s and the other doped with Si to a concentration of about IXIO"cm-", 4Ga6. &^S is buried and grown to form a p-type conductive region 5p and an n-type conductive region 5.
Let it be n.

For example, gold/zinc (Au/Zn) is formed on this p-type conductive region 5p.
) using p@electrode 9p, n-type R1j1w4Jjli
For example, gold germanium/gold (AuGe/A
n (IJ electrode 9n is arranged using u).

In this embodiment, the p-type and n-type conductors 1 are formed in regions 5p,
5n is formed by buried growth of each semiconductor layer, but it may also be formed by selectively thermally diffusing impurities to disorder the superlattice structure as in the conventional example.

Furthermore, although the above-described embodiments use GaAs/AlGaAs-based semiconductor materials, the semiconductor light-emitting device according to the present invention can be similarly constructed using other semi-quadramid materials such as InP/InGaAsP-based materials.

〔Effect of the invention〕

As explained above (according to the present invention), a horizontal semiconductor light-emitting device having a brainer shape with good light confinement and current confinement due to a difference in refractive index and easy electrode extraction can be easily formed without the constraints of the conventional example. It is suitable for 0EIC, and has excellent characteristics such as low threshold current and high efficiency.
Since it is possible to further improve the optical communication technology by optimizing the optical communication, it will have a great effect on the progress of optical communications and the like.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a semiconductor light emitting device of the present invention, FIG. 2 is a schematic sectional view of an embodiment, and FIG. 3 is an explanatory diagram of a conventional example. In the figure, 1.1° is the high resistance cladding 5 (AIGaAs), 2 is the superlattice structure, 2^ is the active layer (GaAs), 2Bp is the n-type barrier layer (AIGaAs), and 2Bn is the n-type barrier layer (AIGaAs). , 4 is n-type camp 5 (Ga
As), 5p is a p-type conductive region (81GaAs), 5n is an n-type conductive region (AIGaAs), 9p is a p-side electrode, and 9n is an n(ll!ITL pole). In the garden

Claims (1)

[Claims] 1) A first semiconductor substrate having a first bandgap in a semiconductor substrate.
and a barrier layer having a second bandgap formed on the first cladding layer and doped with acceptor impurities and donor impurities alternately. a superlattice structure in which an active layer having a narrower third bandgap is formed; and a second high-resistance cladding layer formed on the superlattice structure and having a fourth bandgap wider than the third bandgap. p-type and n-type conductive regions that reach the first cladding layer from the surface of the semiconductor substrate and face each other via the superlattice structure; 1. A semiconductor light emitting device comprising electrodes in contact with conductive regions of a mold. 2) The semiconductor light emitting device according to claim 1, wherein the superlattice structure constitutes a quantum well in which the active layer is a well layer.