JPS62137883A - Junction type semiconductor light emitting element - Google Patents

Abstract

PURPOSE:To efficiently emit light in the vertical direction to a flat plate part by a method wherein electrodes are provided on the top surface of columnar protrusion and the surface of flat plate part and/or a columnar protrusion sidewall. CONSTITUTION:A light emitting element is composed of a flat plate part B, a columnar protrusion P provided on one side of the flat plate part B, electrode E1 provided on the surface of flat plate part B and the side peripheral part of columnar protrusion P as well as another electrode E2 provided on the top surface of columnar protrusion P. A cylindrical P-N junction PN1 extending in the vertical direction direction to the flat plate part B is situated in the columnar protrusion P. Besides, another P-N junction PN2 extending in parallel with said flat plate part B is situated in the flat plate part B. In such a constitution, the P-N junction PN1 only in the vertical direction to the substrate actually emits light while another P-N junction extending in parallel with the flat plate part B hardly emits light making it feasible to effectively use the light in the vertical direction.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor light emitting device that can be used as a light emitting diode or a semiconductor laser. The present invention relates to a junction type semiconductor light emitting device that emits light.

[Conventional technology]

Light-emitting elements that emit light in a direction perpendicular to the substrate are easy to couple with optical fibers, and are expected to have various uses as surface emitters, so research into semi-quadramid lasers and light-emitting diodes is underway. Development has been progressing in this field, and many types have been put into practical use in recent years.

As shown in FIG. 4, a preferable vertical light-emitting element includes a flat plate part B, a columnar projection P provided on one side of the flat plate part B, an upper surface of the flat plate part B, and a columnar projection P provided on one side of the flat plate part B. It consists of an electrode E1 provided on the side wall surface of the columnar protrusion P and an electrode E2 provided on the bottom surface of the flat plate part B, and within the columnar protrusion P there is a cylindrical electrode extending perpendicularly to the flat plate part. p-n
(hereinafter referred to as p-n junction PNI), and the flat plate part has a p-n junction (hereinafter referred to as p-n junction PNI) extending parallel to the flat plate part.
-n junction PN2), and a circuit C1 passing through the pn junction PNI.
A circuit has been proposed in which there are two circuits, ie, a circuit C2 that passes through the p-n junction PN2, and the current densities J1 and J2 generated in the circuits CI and C2 satisfy the formula (Jl>0.IJ2 (+)). There is.

[Problem that the invention seeks to solve]

However, in such a junction-type semiconductor light emitting device, of the two types of p-n junctions, only the p-n junction PNI is useful, and the p-n junction PN2 only brings about horizontal light emission; It is an abomination. Therefore, p-
The n-junction PN2 does not emit light as much as possible, and the p-n junction PNI
The emergence of a junction type semiconductor light emitting device that emits light more efficiently has been eagerly awaited.

Therefore, an object of the present invention is to provide a junction type semiconductor light emitting device that efficiently emits light in a direction perpendicular to a substrate (flat plate portion).

[Means for solving problems]

This object is achieved by the present invention, which is composed of a flat plate part and a columnar protrusion provided on one side of the flat plate part, and includes a p-n junction extending in the columnar protrusion at least in a direction perpendicular to the flat plate part. The problem is solved by a junction type semiconductor light emitting device having an electrode provided on the top surface of the columnar projection, the upper surface of the flat plate portion, and/or the side wall surface of the columnar projection.

Hereinafter, the present invention will be explained in detail based on the drawings.The light emitting device of the present invention basically consists of a flat plate part B and a columnar projection I) provided on one side thereof, as shown in FIG. 1a, for example. , the columnar projection I of the flat plate part B] the shadow-forming surface (that is, the upper surface of the flat plate part B), the electrode JIEI provided on the side circumference of the columnar projection P, and the electrode E2 provided on the top surface of the columnar projection P. It consists of The electrode E1 and the electrode E2 are not limited to the positions and sizes shown in FIG. It is set in the size of The electrode E2 provided on the top surface of the columnar projection P may be provided on the entire surface of the top surface, but if light emission in an upward direction is taken into consideration, the electrode E2 provided on the top surface of the columnar projection P may be provided on a part of the top surface so that light can be emitted. It is preferable to provide only the Inside the columnar projection P, there is a cylindrical p-n junction PNI extending perpendicularly to the flat plate part B, and inside the flat plate part B, there is a cylindrical p-n junction PNI extending parallel to the flat plate part B. p-n
Junction PN2 is present.

FIG. 2 shows another embodiment of the present invention. In the embodiment of FIG. 2, there is no p-n junction PN2 extending parallel to the flat plate portion B, and the electrode E1 is substantially It differs from the embodiment shown in FIG. 1a only in that it is provided only on the side circumference of.

Thus, in the embodiment of FIG. 2, since there is no horizontal pn junction PN2 with respect to the flat plate portion B, vertical light can be acquired more efficiently.

In the present invention, the method for forming a pn junction is as follows:
There are no particular restrictions, and examples include impurity diffusion, epitaxial vapor growth of a p (or n) type semiconductor layer and an n (or p) type semiconducting layer (in this case, heterojunction is also possible). ) or by other methods.

In the present invention, the length of the p-rin junction NI contributing to vertical light emission can be increased by increasing the height of the columnar protrusion P, so the height of the columnar protrusion P is at least 2 mm, especially It is possible to form columnar protrusions P on the surface of a semiconductor wafer, which is preferably at least 10, -, by using, for example, a reactive ion etching method, and can form columnar protrusions extending several tens to hundreds of meters long. The light emitting device of the present invention having I) can be easily manufactured.

Regarding the present invention, the meaning of "vertical direction" in the columnar protrusion P does not need to be limited to a direction perpendicular to the flat plate part B at an angle of 90 degrees; Also included are cases where the angle of inclination is small. For example, the entire columnar protrusion P or only the coaxial cylindrical p-n junction PNI formed inside it may be formed into a trapezoidal shape with a larger diameter at the bottom, making it easier to couple to the optical fiber. The output light may be converged like this, or conversely, the output light may be shaped into a truncated cone, which is the opposite of the above, and it may be diverged appropriately depending on the purpose of use.

The light-emitting materials used in the junction type semiconductor light-emitting device of the present invention include GaAs, AffiGa, which is a -V group compound semiconductor.
As, Ink, InGaAsP, Inc; aP, InA
sSb, , GaAsP, GaN, 1nAsP, InAs
Sb, etc., n-vi group compound semiconductors Zn5e, Zn
S,, ZnO,, Cd5eSCdTc, etc., or rV
-Vl group compound semi-semiconductor PbTe, Pb5nTc
, Pb5nSc, etc., and it is possible to apply them by taking advantage of their respective advantages.

An example of a method for manufacturing a junction type semiconductor light emitting device of the present invention is a Ga
As-A7! A case where a GaAs-based semiconductor material is used will be explained (see the flow sheet in FIG. 3).

First, n-type Al is placed on the n-type Ga As 5 plate B3.
FiB2 of 1xGal-xAs and n-type GaAsI protein A for forming columnar protrusions P and upper layer B1 are sequentially eviaxially grown to produce a 3-layer + 1ζ-structured heterowafer (Fig. 3). C), the j7 size of each jaw is, for example, [B2 is 2 to 50 doors, and the top layer is 2 to 200 doors. For this hetero wafer, the uppermost n-type GaΔs layer is ion-etched using, for example, a reactive ion etching method to form columnar protrusions P (see Figure 3). The remaining portion becomes the upper PJB1. On the top surface of the columnar protrusion P, there is a mask layer applied during the above etching process, but the core mask layer is molded into the desired p-+1 junction PNI shape. The side peripheral wall and the upper part 1 of the columnar projection P remain on the two sides of the "top of the projection P."
When an impurity, for example Zn, for forming n-type conductivity is spread from the surface of fflB1 (see FIG. 3C), the diffusion front toward the substrate B3 is formed by the barrier JiB.
Let it penetrate into 2. Thus GaAs homozygous p
-n junction PNI and AI! GaAs homozygous p-
An n-junction PN2 is formed respectively. ' After the diffusion process, the side peripheral wall of the columnar projection P'- and/
Alternatively, the electrode E1 is attached to the upper surface of the flat plate portion B, and the electrode E2 is attached to the top surface of the columnar projection P. In this way, a junction type semiconductor light emitting device having the configuration shown in FIG. 1 is manufactured. In addition,
FIG. 1 is a diagram showing FIG. 1a in more detail. In addition, when forming the columnar protrusion P by etching, the etching is performed at a high degree of kneading to form the upper part P! It may be arranged so that no Bl remains, or even a part of the barrier layer B2 may be removed so that the inside of the barrier layer B2 is exposed on the surface of the flat plate part B.

The junction type semiconductor light emitting device having the configuration shown in FIG. 2 is manufactured, for example, as follows.

That is, the top of the columnar projection of the semiconductor light emitting device shown in FIG. 3 (preferably, the mask layer 1 is provided on the top surface of the columnar projection P. However, the mask layer 1 is omitted in FIG. 3).
A mask layer 2 is provided on the surface of the flat plate portion, and impurity diffusion (preferably zinc diffusion) is performed on the side peripheral wall of the columnar protrusion P in an unmasked state to substantially form the flat plate portion inside the columnar protrusion P. It is manufactured by forming only a p-n junction PNI extending perpendicularly to the p-n junction (see FIG. 3C).

The electrode E1 and the electrode E2 may be provided by means known per se, for example, by providing them on the entire surface by means such as vapor deposition, and removing unnecessary electrodes by lift-off. In this way, a junction type half-four-body light emitting device having the configuration shown in FIG. 2 is manufactured.

In the semiconductor light emitting device thus obtained, a reflective mirror or a reflective film is provided on the opposite surface of the columnar projection P of the flat plate portion B, and a translucent reflective mirror or reflective film is coated on the top surface of the columnar projection P. If the optical resonance mechanism is set to 0iit, it can also be used as a semiconductor laser. In this half-four body laser, optical feedback occurs in the above-mentioned amplified spontaneous emission from the p-n junction PN1, and laser oscillation occurs due to stimulated emission, and the strong and well-directed emitted light is emitted as described above. The light is emitted in a direction perpendicular to the flat plate portion B through a semi-transparent reflective mirror or reflective film.

[Effect]

The junction type semiconductor light emitting device of the present invention has the effect that only the pn junction PNI in the direction perpendicular to the substrate substantially emits light.

〔effect〕

As is clear from the above effects, the junction type semiconductor light emitting device of the present invention can effectively obtain light in a direction substantially perpendicular to the flat plate portion B; Even if the existing p-n junction PN2 exists, it hardly contributes to light emission and can effectively utilize light in the desired vertical direction. The light-emitting device of the present invention can obtain more powerful vertical output light by utilizing the amplification effect of stimulated emission, and can realize light-emitting diodes, semiconductor lasers, superluminescent diodes, high-output light-emitting diodes, etc. .

[Brief explanation of drawings]

FIGS. 1a and 2 are cross-sectional views of embodiments of the junction type semiconductor light emitting device of the present invention. FIG. 1 is a perspective view showing a partial cross section showing FIG. 1a in more detail. FIG. 3 is a flow sheet of an example of manufacturing the junction type semiconductor light emitting device shown in FIG. 1a (FIG. 1b) and FIG. FIG. 4 is a sectional view of a conventionally known junction type semiconductor light emitting device. B: Flat plate part P: Columnar projection El, B2: Electrode C1, C2: Circuit PNI, PN2: p-n junction B1: Upper layer B2: Barrier JR B3: Law (anti-A
:n-type GaAs layer 112 :mask layer

Claims (1)

[Claims] In a junction type semiconductor light emitting device, which is composed of a flat plate part and a columnar protrusion provided on one side of the flat plate part, and has a p-n junction extending perpendicularly to the flat plate part in at least the columnar protrusion, the columnar A junction type semiconductor light-emitting device in which electrodes are provided on the top surface of a protrusion, the upper surface of a flat plate part, and/or the side wall surface of a columnar protrusion.