JPS603167A - Manufacture of semiconductor light-emitting diode - Google Patents

Abstract

PURPOSE:To prevent a creeping to a back electrode of an Au plating liquid, and to obviate a contamination by previously coating an electrode with an opening for extracting beams formed on the back of a substrate with a ZnO film having small conductivity when an Au plated layer is formed on an electrode layer as an uppermost layer constituting a light-emitting diode. CONSTITUTION:An N type InP buffer layer 2, an InGaAsP active layer 3, a P type InP re-lade layer 4 and a P type InGaAsP cap layer 5 are laminated on an N type InP substrate 1 and grown in an epitaxial manner, and an SiO2 film 6 for constricting currents, a central section thereof has a striped shape, is formed on the layer 5. A P-side ohmic contact metal 7 is applied while burying the striped shape and an Au plated film 11 is formed on the metal 7, but a back N- side ohmic contact metal 8 with an opening 12 for extracting beams previously formed is coated beforehand with a ZnO film 10 having very small conductivity at that time. The film 10 is removed, and an antireflection film 9 consisting of an SiO2, etc. is applied to the removed section of the film 10.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a semiconductor light emitting diode.

Semiconductor light emitting diodes have been widely used in recent years for applications such as excitation, and various improvements have been made to improve their characteristics. Among semiconductor light emitting diodes, surface emitting type light emitting diodes are provided with an anti-reflection film on the window surface on the main output side in order to improve the output power. Furthermore, for the purpose of improving the reliability of the device, an attempt has been made to cover the ohmic conductive electrode formed on the surface opposite to the light output extraction window with a thick Au plating film to improve the heat dissipation properties. Conventionally, as mentioned above,
To fully manufacture a surface emitting diode equipped with an anti-reflection film and an Au plating film, multiple semiconductor layers (active layers, etc.) are fully grown on the substrate, and a multilayer semiconductor wafer (hereinafter referred to as wafer) is fully formed. , all ohmic contact portions with current confinement are provided on the surface of the semiconductor layer growth 111j of the wafer (hereinafter referred to as the wafer surface).First, the surface facing the front surface of the wafer (hereinafter referred to as the back surface) is provided. ) After polishing the substrate to make it thinner, remove the light output window? Is the ohmic contact electrode and anti-reflection film fully formed, followed by a heat dissipation effect on the wafer surface? A process of providing Au plating Mk is being carried out to improve the quality. Au
The reason why the plating process is performed last is to avoid stress caused by the thick Au plating layer and alloying due to the reaction between Au and Ueno during the heat treatment required to provide ohmic contact electrodes on the back side of the wafer. At the same time, a thinly polished wafer with an Au plating film of 'kV' has a large reaction, so it is difficult to attach it to glass, etc. of the entire wafer in the photoresist process for opening the electrode bar and buttering the anti-reflection film. Because it will be. However, even if the conventional method of performing Au plating at the end of the entire process is adopted, there are drawbacks as described below. In the Au plating process, thinned Ueno-
Plating is carried out with the whole surface of the wafer pasted on a glass plate for support using photoresist, etc., but during plating the wafer gradually warps, and a peeling tray occurs between the back side of the wafer and the glass plate. A problem arises in that the Au coating liquid flows back onto the back surface of the wafer and contaminates the electrode surface. When such stains occur, not only does the appearance deteriorate, but also the adhesion force when installing lead wires is greatly reduced.

An object of the present invention is to provide a method for manufacturing a semiconductor light emitting diode in which the ohmic contact electrode on the side of the light output extraction window is not easily contaminated by the Au plating solution during the Au plating process.

The method for manufacturing a semiconductor light emitting diode according to the present invention includes an active layer? a step of fully forming a multilayer semiconductor wafer by growing a plurality of semiconductor layers on a substrate, and fully forming a first ohmic electrode with a current confinement structure on a first surface of the semiconductor wafer on the semiconductor layer growth side; a step of completely forming a second ohmic electrode having an opening for taking out the original output on the a)↓2 surface facing the first surface of the multilayer semiconductor urchin; The process of completely forming the covering anti-reflection film and the second ohmic film? 'b, K and the ZnO film covering the anti-reflection film? The process of forming and this ZnO
The method includes a step of plating Au on the first ohmic contact after film formation, and a step of removing the ZnO film after the Au plating step.

The present invention will now be described in detail with reference to all the drawings.

FIGS. 1A to 1H are cross-sectional views of semi-finished products in intermediate steps according to an embodiment of the present invention. The substrate l used in this example is n-type InP.

In this figure (ta), an n-type InP buffer layer of 2° InGa is formed by continuous epitaxial growth on an n-type InP substrate 1.
AsP active layer 3. P-type IrKP cladding layer 4°p-type In
The GaAs'P cap layer 5 is shown grown on a wafer gold. FIG. 1(b) shows the p-type InGaAsP cap layer 5 on the surface of the double heterostructure wafer shown in FIG. 1(a).
After an insulating film 6 made of 5 iOz or the like for current narrowing is completely formed on top, a semi-finished metal is shown in which an opening metal is provided by a photoresist process. In the same figure (C), a p-side ohmic contact metal 7'! i: After being deposited,
Semi-finished tap water that has been heat treated to achieve ohmic contact. Same figure (
dJ is % InP substrate l? After polishing, 8 n-side ohmic contact metals were deposited, and 12 openings for taking out the 9 elements were formed using a photoresist process, followed by heat treatment.
Ohmic contact on the n side? The intermediate product obtained is tap water. The same figure (e
), the anti-reflection film 9 of SiNx, 5i02, etc. is completely deposited on the opening 12 for removal by plasma CVD or sputtering, and then subjected to a photoresist process.
1 shows an intermediate product that has been subjected to rainbow butterning. In the same figure (f), Zn with a thickness of about 0.5 to 1 μm is deposited by sputtering.
A semi-finished product is shown in which the ZnO film 10e, the n-side ohmic contact metal 8 and the anti-reflection film 9 are coated, and the unique feature of the present invention lies in the step of forming one ZnO film. In the same figure (g), after pasting the ZnO film 10 on a support such as a sidetone glass plate using photoresist or the like, an Au plating film is applied on the p-side ohmic contact metal 7 using a photoresist process. 11?
Selectively provided semi-finished products? show. In this Au plating process, since a very small ZnO film IO with 1δ conductivity is deposited on the nulj ohmic contact metal 8,
It is possible to avoid contamination of the n-side ohmic contact metal 8 shin surface caused by the Au plating solution being squeezed in in the conventional manufacturing method. In this figure (h), the ZnO film 10 is diluted with pure water.
Very easily dissolved in dilute phosphoric acid solution at room temperature of about 1%
A semi-finished product from which gold has been removed from a ZnO film is shown below.

At 00:00, the antireflection film 9 made of 5iiNx, 5i02, etc. is not immersed.
The 8th Conf-(1976Interna
tional) ovx 5olid 5tate De
vices, Tokyo; 43-6-21 and Japanese Patent Application No. 124930/1980).

The semi-finished product in Fig. b<i (h) is completed as a surface-emitting detection diode using InP as a substrate through processes such as element separation and lead wire attachment.

As described above, based on the present invention, when using the conventional manufacturing method of surface-emitting type semiconductor light emitting diodes, the plated film, which often occurs when removing the Au plating for heat dissipation, is removed from the surface on which the entire plating film is not formed. Contamination of the provided electrodes by the plating solution is greatly reduced, the external LQt of the device is not damaged, and the adhesion of the lead wires can be strengthened. In addition, in the above embodiments, all cases are shown when using an InP substrate, but a surface-emitting type diode k
The present invention is also applicable to the case of manufacturing.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(h) are cross-sectional views showing semifinished grapes in each intermediate step in an embodiment of the present invention. 1...n-type InP substrate, 2...n-type I
One layer of nP buffer, total... InGaAsP active layer, 4... p-type 1 nP cladding layer, 5...
...p-type InGaAsP cap layer, 6...
Insulating film, 7...p 9 (11 ohmic contact metal, 8...n side ohmic contact gold #b9...
...Antireflection film, 10...ZnO film, 11.
...Au plating film, 12...Original removal opening. Agent f1 Rishinai J Kyo Susumu. (t2.n IC), 〆. Early 1

Claims (1)

[Claims] forming a multilayer semiconductor wafer by growing a plurality of semiconductor layers including an active layer all over the substrate; a second ohmic electrode having an opening for taking out the original output on a second surface of the multilayer semi-donor wafer facing the first surface; a step of forming an anti-reflection film overlying the opening; a step of forming a ZnO film covering the second ohmic electrode and the anti-reflection film; and after forming the ZnO film, plating Au on the first ohmic electrode. A method for manufacturing a semiconductor light emitting diode containing gold, including a step of applying gold, a step of removing the ZnO film after the metallization step.