JPH06112532A - Method for forming electrode of semiconductor element - Google Patents

Abstract

PURPOSE:To provide a method by which the electrode of a semiconductor light emitting element can be formed so that the electrode can maintain high reliability for a long period. CONSTITUTION:In the title method in which an electrode is formed by successively depositing a contact film 11, barrier film 12, and Au film 10 on a semiconductor element constituted by forming a current blocking layer 2 having a current constricting window and made of a semiconductor and insulating film 1 with a current constricting window having a larger window area than the layer 2 does, the Au film 10 is formed after the contact film 11 and barrier film 12 are successively formed and the films 11 and 12 are subjected to heat treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming electrodes of a semiconductor device.

[0002]

2. Description of the Related Art As a current confining means in a semiconductor device,
A method is known in which an insulating film such as SiO ₂ or SiN _x is provided with a constriction current passage portion having a size corresponding to a current flow path, and an electrode metal layer is deposited on the constriction current passage portion. By the way, InGaAsP
-Based or GaAs-based light emitting diode elements have been attracting attention as devices for medium-range, large-capacity optical communication. This device has a high coupling efficiency with the optical fiber in order to extend the communication distance, increase the capacity, and improve reliability.
A high response speed and high reliability are required, and the above-mentioned electrode forming method is used. The conventional light emitting diode element has a blocking type structure as shown in FIG. 2, for example, and is manufactured as follows. That is, 1) n-
InP substrate 6, p-InGaAsP active layer 5, p-In
P clad layer 4, p-InGaAsP cap layer 3, I
The nP current blocking layer 2 is sequentially laminated. 2) Next, a silicon-based insulating film 1 such as SiO ₂ is formed. 3) Next, the insulating film 1 and the current blocking layer 2 are concentrically and circularly removed to form a p-electrode 9 made of a Ti contact film / Pt barrier film / Au film, and an n-electrode 8 made of AuGeNi. To do. When forming the p-electrode 9, as shown in, for example, FIG.
Contact film 11 made of 0Å Ti film, barrier film 12 made of 2000Å Pt film for preventing Au diffusion, 2
The 000Å Au film 13 is sequentially laminated. In this way, the Au film 13 directly contacts the p-InGaAsP cap layer 3 and the InP current blocking layer 2 to prevent Au from migrating, thereby preventing the device from deteriorating. 4) Finally, the Au plating layer 10 is formed on the p electrode 9 to flatten it. In the light emitting diode having such a structure, since the light emitting region is limited, the coupling efficiency with the optical fiber can be improved. Further, by interposing the current blocking layer 2 between the cap layer 3 and the insulating film 1,
By separating the insulating film 1 and the cap layer 3 having different thermal expansion coefficients from each other, it is possible to prevent deterioration due to defects caused by thermal stress between them, and it is possible to improve reliability.

[0003]

However, the above-mentioned light emitting diode element has the following problems.
That is, in the step portion 14 of the InP current blocking layer 2, step breakage occurs in the contact film 11 and the barrier film 12, and the Au film 1
3 may contact the InP current blocking layer 2. Therefore, the Au film 13 and the InP current blocking layer 2 react with each other by the heat treatment after the formation of the p electrode 9 for stabilizing the electrical contact between the cap layer 3 and the Ti contact film 11, and Au reaches the vicinity of the active layer 5. There is a risk of diffusion and deterioration of the reliability of the device.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for forming electrodes of a semiconductor device, which solves the above problems. A current blocking layer made of a semiconductor having a current constriction window on a semiconductor layer and the current constriction window. In a method of forming an electrode of a semiconductor element, an electrode having a contact film, a barrier film and an Au film stacked on a semiconductor element having an insulating film having a current confinement window having a larger window area than the contact film and the barrier film. It is characterized in that after the films are sequentially laminated, a heat treatment is performed, and then an Au film is laminated.

[0005]

As described above, when the contact film and the barrier film are sequentially laminated, then the heat treatment is performed, and then the Au film is laminated, the Au film is not subjected to the heat treatment. Therefore, the Au film contacts the current blocking layer made of a semiconductor. However, Au can be prevented from entering the current blocking layer.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a cross-sectional view of an embodiment of a light emitting diode manufactured by using the method of forming electrodes of a semiconductor device according to the present invention. This example was manufactured as follows. That is, 1) n-
InP buffer layer 6, p-InGaAsP active layer 5, p
-InP clad layer 4, p-InGaAsP cap layer 3, and InP blocking layer 2 are sequentially stacked. 2) Next, a silicon-based insulating film 1 such as SiO ₂ is formed. 3) Next, the insulating film 1 and the current blocking layer 2 are concentrically and circularly removed. Up to this point, the process is the same as the conventional technique. 4) Next, contact film 1 consisting of 1000Å Ti
1, 2000 Å Pt barrier film 12 is sequentially formed, then AuGeNi n electrode 8 is formed,
Heat treatment is performed. Finally, the Au plating layer 10 is formed,
A p-electrode is formed. The p-electrode thus formed is
Since the heat treatment is performed before forming the Au plating layer 10,
Even if the Au plating layer 10 contacts the current blocking layer 2,
It is possible to prevent Au from diffusing into the InP current blocking layer 2. It goes without saying that the present invention is not limited to light emitting diodes and can be applied to semiconductor elements having a current constriction structure.

[0007]

As described above, according to the present invention, a current blocking layer made of a semiconductor having a current confinement window on a semiconductor layer and an insulating film having a current constriction window having a larger window area than the current confinement window are provided. In an electrode forming method of a semiconductor element, wherein an electrode having a contact film, a barrier film and an Au film laminated thereon is formed on the formed semiconductor element, a contact film and a barrier film are sequentially laminated, heat treatment is performed, and then an Au film is formed. Since Au is laminated, there is an excellent effect that a reliable semiconductor light emitting device can be manufactured without Au being diffused into the semiconductor.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a light emitting diode manufactured by using a method of forming electrodes of a semiconductor device according to the present invention.

FIG. 2 is a cross-sectional view of a conventional light emitting diode device.

FIG. 3 is a partially enlarged view of the above sectional view.

[Explanation of symbols]

 1 Insulating Film 2 Current Blocking Layer 3 Cap Layer 4 Cladding Layer 5 Active Layer 6 Buffer Layer 7 Substrate 8 n Electrode 9 p Electrode 10 Au Plating Layer 11 Contact Film 12 Barrier Film 13 Au Film 14 Stepped Section

Claims (1)

[Claims] 1. A contact film is formed on a semiconductor element having a current blocking layer made of a semiconductor having a current confinement window on a semiconductor layer and an insulating film having a current confinement window having a larger window area than the current confinement window. In a method of forming an electrode of a semiconductor element, which comprises forming an electrode in which a barrier film and an Au film are laminated, a contact film and a barrier film are sequentially laminated, heat treatment is performed, and then an Au film is laminated. Electrode forming method.