JPS6070782A - Manufacture of light-emitting diode - Google Patents

Abstract

PURPOSE:To prevent the inequality or lowering of the quantity of light emission and the shortening of life by dividing a light-emitting section into a plurality of fine regions and preventing corrosion on etching by utilizing a mask. CONSTITUTION:A mask 2 for selective diffusion is formed on a substrate 1, and a lattice 4 is shaped to the through-hole 3 of the mask 2. The lattice 4 divides the through-hole 3 into a plurality of regions, and is formed by a striped or parallel cross-shaped diffusion mask material, and width W is made narrower than side diffusion length. Diffusion regions 5 are connected mutually and a continuous P-N junction 6 is obtained on diffusion from the through-hole 3. An electrode film 7 consisting of aluminum or an aluminum alloy is evaporated on the whole surface, an etching mask 8 is formed, and the whole surface is etched by a phosphoric acid group etchant. The quantity of the substrate by the etchant is extremely small because an exposed section in the surface of the substrate 1 is partitioned into small sections by the lattice 4.

Description

DETAILED DESCRIPTION OF THE INVENTION A) Field of Industrial Application The present invention relates to a method of manufacturing a light emitting diode with a uniform light emitting surface, which is particularly suitable for printer heads and the like.

(2) Prior art In general, as shown in Figure 1, pn junction <1 is formed by selective diffusion.
6) and when emitting light in its diffusion region (15), an electrode (17) is attached to this diffusion region (15) and power is supplied. In this case, the electrode (17) is M
Then, a polar material is deposited, and a photolithography technique is used to leave a desired portion and expose a light-emitting portion on the surface. In the etching process, the etchant for the electrode material often does not dissolve the compound semiconductor; for example, the etchant for the gold thread electrode is
Erachan l- (phosphoric acid) for aluminum-based electrodes dissolves GaAsP-based compound semiconductors well, but the impurity concentration due to diffusion decreases as the diffusion depth increases, resulting in high resistance. The side has lower resistance. Therefore, as the electrode (17) is etched, the semiconductor surface is also melted and a recess (11') appears, causing the current to flow unevenly (current is difficult to flow in the center or at the other end of the electrode), resulting in a dark display. or the lifespan will be shortened. This is not noticeable in a display device that is directly visible, but in displays such as cameras and printer heads, the object (film or photosensitive drum) is exposed to light depending on the state of the light emitted, and especially in optical blinking, the blinking head Since it is the heart of the equipment, it is inconvenient if its lifespan is short.

C) Purpose of the Invention The present invention has been made to improve the above points.

2) Structure of the Invention The present invention utilizes the side diffusion that occurs during diffusion to form a wide light-emitting region as before, but at least when etching the light-emitting region using a mask, the light-emitting region is It is divided into 4'y areas to prevent erosion.
The present invention will be described in detail below based on examples.

E) Embodiment FIGS. 2(a) to 2(f) are process diagrams illustrating a method for manufacturing a light emitting diode according to an embodiment of the present invention. First, the second ward <a
) A compound semiconductor substrate (1) is prepared as shown in (1), and the explanation will be given assuming that a printer head (the light emitting part is a square with a side of 50 μm) is manufactured using GaAsp laminated on GaAs. .

A mask (2) for selective diffusion is provided on this substrate (1).As shown in FIG.
) is provided with a grid (4). This lattice (4) divides the through hole (3) into a plurality of regions, and is formed using a diffusion masking agent in the form of stripes or fingers, and its width (W> is narrower than the side diffusion length). Here, side diffusion refers to a phenomenon in which the diffusion method appears on the surface side of the substrate relative to the thickness and size of the through-hole in the mask, and the diffusion occurs over an area larger than the through-hole. Place the diffusion area below.

Therefore, when diffusion is performed through this through hole (3), the same figure (
As shown in C), the diffusion regions (5) are connected to each other,
A continuous pn junction (6) is obtained. For example, 700°C
When the -cp type impurity is diffused for 2 hours, 1xide diffusion is performed, so the side diffusion length (2xide diffusion length) is about 5 μm. Therefore, [the above grid 4)-11] W
) is 5 .mu.m or less.However, in consideration of yield and luminescence amount, 80% 1" (4 .mu.m or less) is preferable.

Then, as shown in Figure 2(d), an electrode film (7) made of aluminum or aluminum alloy is deposited on the entire surface.
), the electrode film (7)'s-etched with a phosphoric acid-based etchant using an engineering mask (8). (See figure (f)) Post-processing/Goog mask (8
) removal, ohmic/etching treatment, etc., or use a diffusion mask (
Since the exposed portion of the surface of the substrate (1) is divided into small sections by the grid (4) of mask (2), the amount of erosion of the substrate by the etchant is extremely small. It may be removed for 10 minutes, or it may be left for surface protection as long as it is transparent to the emission wavelength.

f) Effects of the Invention As described above, the present invention provides a method for manufacturing a light emitting diode in which a mask having through holes is provided on the surface of a compound semiconductor, and a p+1 junction is formed by selectively diffusing through the through holes of the mask. Since the through holes in the mask break the lattice of 1] which is narrower than the side diffusion length, they do not have a wide light emitting region of continuous p-n junctions, so the surface is eroded in the subsequent process and the amount of light emitted is unrestricted. Or, there is no deterioration, and the lifespan is not shortened.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a light emitting diode produced by a conventional manufacturing method, and FIGS. 2(a) to 2(f) are process diagrams illustrating a method of manufacturing a light emitting diode according to an embodiment of the present invention. (1) Substrate (compound semiconductor), (2) Mask (for diffusion), (3> Through hole, (4) Lattice, (5
) ・Diffusion region, (6 pn junction, (7)...electrode film, (13) etching mask.

Claims (1)

[Claims] 1> Provide a mask with through holes on the surface of the compound semiconductor,
By selectively diffusing pn through the holes in the mask,
A method of manufacturing a light emitting diode forming a junction, wherein the through hole of the mask has a lattice whose width is narrower than the Zide diffusion length.