JPS5942471B2 - Method for manufacturing semiconductor light emitting device - Google Patents

Description

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

In a semiconductor light-emitting device, for example, a GaP light-emitting diode, the electrodes formed thereon must have good ohmic contact, reflect light emitted from the PN junction surface with high efficiency, and have good bonding characteristics during assembly. The following characteristics are required. However, in the past, when forming an electrode, in order to obtain good ohmic contact, a single metal such as Au or Au-Be was used in the P-type region.
A multi-component metal such as Au-Zn is replaced with a single metal such as Au or Au-Ge3Au-Si, Au-Ge3 in the N-type region.
- Multi-component metals such as Ni are deposited and heated to create electrodes with ohmic contacts. However, during this process, GaP and these metals react, and Ga
Not only does the reaction layer (change layer on the surface of the metal) of P and metal on the surface of the metal on the GaP side absorb light, but also the heat treatment causes Ga to diffuse into the metal layer, improving bonding properties. In some cases, this may cause deterioration. The object of the present invention is to reflect light with high efficiency without damaging ohmic contact and to ensure good bonding properties.

This invention involves depositing a single metal or a multi-component metal on the surface of a semiconductor substrate, and then performing heat treatment while depositing it to react with the metal on the surface of the semiconductor substrate, and then dissolving and removing the metal. The method is characterized in that a metal having good bonding properties is newly attached to the surface. As described above, by causing the surface of the semiconductor substrate to react with the metal, a metamorphic layer reacted with the metal is formed on the surface of the semiconductor substrate.

Since the metal can provide ohmic contact with the semiconductor substrate, the metamorphic layer can also provide ohmic contact. After the metamorphic layer is formed, the metal (including the reaction layer changed on the surface of the metal on the semiconductor substrate side) is dissolved and removed while leaving the metamorphic layer, thereby avoiding light absorption by the reaction layer. be done. Then, since a metal having good bonding properties is separately deposited, good bonding properties are ensured. When depositing this metal, for example, by vapor deposition, it is desirable to perform the treatment at the lowest possible temperature to prevent the metal from reacting with the metamorphic layer as much as possible. An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. Metals 4a and 4b having ohmic contact characteristics are attached to the contacts (see FIG. 2).

). The metal 4a attached to the P-type region 1 is Au, A
u-Be, Au-Zn and its nickel compound, and as the metal 4b attached to the N-type region 2, Au, Au-G
E, Au-Si, Au-Ge-Ni and their nickel compounds are suitable. After depositing the metals 4a and 4b, heat treatment is performed at, for example, 520° for 10 minutes in a hydrogen atmosphere, so that a reaction occurs between each metal and the semiconductor substrate, and metamorphosed layers 5a and 5b are formed on the surface of the semiconductor substrate due to the reaction. (See Figure 3.) Next, the metals 4a and 4b are Au
In the case of -Be, Au-Ge-Ni, the metals 4a and 4b are dissolved and removed by etching with a mixed solution of 12 and KI (see FIG. 4). After this removal, bonding metals 6a and 6b (for example, Au) are deposited by vapor deposition or the like (see FIG. 5). Next, the metal 6a is suitably photo-etched (see Figure 6) and divided into pieces by dicing or the like (see Figure T). At this time, if a strained layer is formed on both side surfaces due to dicing, the strained layer is removed by chip etching. It is convenient to use chemically resistant metals as the metals 6a and 6b, since the electrodes can have chemical resistance. Next, the characteristics of the product obtained by the manufacturing method according to the present invention will be explained in comparison with those of the product obtained by the conventional manufacturing method.

(b) Luminance The luminance of the conventional example was 565 μCd, while the brightness of the present invention was 1064 μCd, about 8
An 8% improvement was seen.

(2) Bonding properties When various types of bonding were performed, the following results were obtained.

From the above table, it is understood that the product according to the present invention can obtain good characteristics no matter what type of bonding is used.

(3) Contact resistance The actual measurement results of contact resistance were as follows.

As will be understood from this, even if the treatment according to the present invention is applied, the resistance of the electrode portion is not affected in any way.
Rather, the resistance is decreasing at the front electrode. As detailed above, according to the present invention, the ohmic metal is attached to the surface of the semiconductor substrate to provide ohmic contact characteristics, and then the ohmic metal whose reflectance has become low due to reaction with the semiconductor substrate is removed. However, since the bonding metal is attached afterwards, it is possible to ensure ohmic contact and to greatly improve the brightness without impairing the bonding characteristics.

[Brief explanation of drawings]

1 to T are cross-sectional views for sequentially explaining the steps of the manufacturing method of the present invention. 3...Semiconductor substrate, 4a, 4b...
Metals with Ohmic properties, 6a, 6b...Metals with bonding properties.

Claims (1)

[Claims] 1. After attaching a metal with ohmic characteristics to the surface of a semiconductor substrate, or while applying heat treatment, the surface of the semiconductor substrate reacts with the metal, whereby the surface of the semiconductor substrate has ohmic contact characteristics. A method for manufacturing a semiconductor light emitting device, comprising forming a metamorphic layer, removing the metal from the surface of the semiconductor substrate while leaving the metamorphic layer, and attaching a metal having bonding properties to the removed surface. .