JPS5812752B2 - Hand-made Thai Hatsukousouchi - Google Patents

Description

[Detailed description of the invention] The present invention relates to a semiconductor light emitting device.

More specifically, the present invention provides a first conductive type semiconductor substrate, a perforated insulating layer provided on the surface of the substrate, and a second conductive type semiconductor substrate provided on the substrate surface in alignment with the holes of the insulating layer. In a semiconductor light emitting device comprising a region, the light emission contour of light emitted through the hole in the insulating layer is made sharp.

FIG. 1 shows a conventional device of this type, in which 1 is an N-type gallium phosphide substrate, 2 is an insulating layer provided on the surface of the substrate and has a hole 3, and 4 is a substrate that is aligned with the hole 3 in the insulating layer. This is a P-type region provided on the surface of 1.

The P-type region 4 is formed in alignment with the hole 3 of the insulating layer 2 by, for example, a selective diffusion technique using the hole 3 of the insulating layer 2 or a selective ion implantation technique.

5 is a PN junction formed by the boundary between the N-type substrate 1 and the P-type region 4, which contributes to light emission.

The insulating layer 2 is used in the manufacturing process of the device to define the area of the P-type region 4, that is, the light-emitting pattern area, or as a surface on which a wiring electrode film connected to the P-type region 4 is laid.

However, the conventional device described above has the disadvantage that the light emitting pattern is blurred despite the presence of the insulating layer 2.

Silicon nitride and silicon oxide are known as suitable materials for the insulating layer 2 in the semiconductor technology field, but all of these insulating layers exhibit light transmittance even at a considerable thickness.
Therefore, in addition to the center emitted light 6 that passes through the hole 3 of the insulating layer 2, there is peripheral emitted light 7 that passes through the insulating layer 2 around the hole 3, and the light emission pattern becomes blurred as if the periphery is blurred.

The peripheral emitted light 7 may enter the insulating layer 2 directly from the P-type region 4, or may be reflected from the bottom surface of the substrate 1 and enter the insulating layer 2, but in either case, the crystal of the substrate 1 is exposed to the emitted light. When the relationship is transparent, for example, when a gallium phosphide crystal and green emitted light are combined, the emitted light easily passes through the crystal.
Therefore, the peripheral emitted light 7 passing through the insulating layer 2 increases, and the phenomenon of blurring of the light emitting pattern is promoted.

The present invention has been made in view of this point, and as shown in the embodiment shown in FIG.
The periphery is characterized in that it is transformed into a semiconductor layer 8 having a bandgap smaller than that of the substrate crystal.

Note that the same parts as in FIG. 1 are given the same numbers.

In the device of this embodiment, the peripheral emitted light 7 directed toward the insulating layer 2 is absorbed or reflected by the semiconductor layer 8 having a smaller bandgap and is not emitted to the outside.

That is, the semiconductor layer 8 functions as a light shielding layer, and therefore the light emission pattern at this time is composed only of the centrally emitted light 6, and there is no bleeding.

FIGS. 2A to 2E show the manufacturing process of the above embodiment device.

To explain this process order below, first, in the process shown in FIG. Arsenic ions are implanted into the surface.

Photoresist 9 is deposited to a thickness of about 1 micron to prevent arsenic ions from being implanted below the substrate surface in the predetermined areas.

Therefore, except for the above predetermined region, the arsenic ion implantation region 10
is formed.

The preferred depth of this region is 1000 Å or more.

Next, in the step shown in FIG. 2B, the photoresist 9 is removed and an insulating layer 2 with a thickness of about 5000 Å is formed on the substrate surface.

Next, in the step shown in FIG. 2C, the arsenic ion implantation region 10 is
Holes 3 are provided in the insulating layer so that the insulating layer 2 remains only on top.

In the subsequent step shown in FIG. 2D, the entire substrate is heat treated at 800°C.

Such heat treatment causes the initial substrate crystal gallium phosphide Gap to change to gallium arsenide phosphide Ga in the arsenic ion implantation region.
Promote recrystallization to Asl-xPx.

As a result, the arsenic ion implanted region is transformed into a semiconductor layer 8 having a band gap smaller than that of the substrate 1 crystal.

Finally, in the step shown in FIG. 2E, a P-type region 4 is provided to a depth of approximately 2 .mu.m by a selective zinc diffusion technique using the holes 3 in the insulating film 2, and the device is completed.

As is clear from the above description, according to the present invention, in a device for extracting emitted light through a hole in a porous insulating layer provided on a semiconductor substrate, at least the vicinity of the hole in the insulating layer on the surface of the substrate is exposed to light. Since it has been transformed into a semiconductor layer that has a shielding effect, it has a simple structure and there is no peripheral emitted light passing through the insulating layer, and the light emitting pattern is formed only by the central emitted light passing through the holes in the insulating layer, and its outline is It becomes sharp.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional example, and FIGS. 2A to 2E are sectional views showing steps of an embodiment of the present invention. 1...N-type substrate, 4...P-type region, 2
...Insulating layer, 8...Transformed semiconductor layer.

Claims (1)

[Claims] 1 Consisting of a first conductivity type semiconductor substrate, a perforated insulating layer provided on the surface of the substrate, and a second conductivity type region provided on the surface of the substrate in alignment with the holes of the insulating layer, the substrate A semiconductor light emitting device, wherein at least a portion of the surface of the insulating layer around the hole is transformed into a semiconductor layer having a bandgap smaller than the bandgap of the substrate crystal.