JPS63232368A - Hybrid optoelectronic integrated circuit - Google Patents

Abstract

PURPOSE:To manufacture a hybrid optoelectronic integrated circuit in a relatively simple step by so face-down bonding a semiconductor light emitting element as to cross over an optical guide to optically couple them. CONSTITUTION:A semi-insulating semiconductor substrate 1, an optical guide 3 formed on the substrate, an electronic element 2 formed on the substrate, and a semiconductor light emitting element 4 of flip chip type are provided, and the element is so face-down bonded to the substrate 1 as to cross over the guide 3 to optically couple the element 4 to the guide 3. Thus, an optoelectronic integrated circuit is obtained in a relatively simple manufacturing step, and reduced in size smaller than the structure of individual components to improve the reliability of the system.

Description

[Detailed Description of the Invention] [Summary] A flip-chip type semiconductor light emitting device is face-down bonded to a semi-insulating semiconductor substrate in which an optical waveguide and electronic elements such as transistors are integrally formed so as to straddle the optical waveguide. Hybrid optoelectronic integrated circuit with optical coupling.

[Industrial application field]

The present invention relates to an optoelectronic integrated circuit (01! IC), and more particularly to an optoelectronic integrated circuit that combines a semiconductor light emitting element, an electronic element such as a transistor, and an optical waveguide.

[Conventional technology]

Research and development has been conducted on optoelectronic integrated circuits in which a light emitting element such as a semiconductor laser or light emitting diode and/or a light receiving element such as a photodiode and an electronic element such as MTS PET are integrated on the same semiconductor substrate, and prototype products have been announced (for example, , Recent examples of optical IC development, Electronic Materials, November 1983 issue, Vol, 22. Na1l, pp, 38-58; Kiribe Kobayashi: “Optical integrated circuit (optical IC)”, Nikkei Microdevices, ■985 July issue, No. 1, pp, 211-
228, see). Furthermore, research on combining optical waveguides is also being conducted.

(Problems to be solved by the invention) Monolithically forming a semiconductor light emitting device, an electronic device, and an optical waveguide on the same semiconductor substrate is extremely complicated, especially since the structures of the light emitting device and the electronic device are significantly different. This makes the production time-consuming and costly.

An object of the present invention is to provide an optoelectronic integrated circuit comprising a semiconductor light emitting device, an electronic device, and an optical waveguide, which can be manufactured through a relatively simple manufacturing process.

[Means for solving problems]

Therefore, the gist of the present invention is to include a semi-insulating semiconductor substrate, an optical waveguide formed on the semiconductor substrate, an electronic element formed on the semiconductor substrate, and a flip-chip type semiconductor light emitting element. The semiconductor light emitting device is face-down bonded to the semiconductor substrate so as to straddle the optical waveguide, and the semiconductor light emitting device and the optical waveguide are optically coupled, which is a hybrid optoelectronic integrated circuit. In short, in the optoelectronic integrated circuit according to the present invention, the light emitting element is separately manufactured and mounted on the semiconductor substrate.

The semiconductor light emitting device is preferably a horizontal injection type laser in which both electrodes (p electrode and n electrode) are formed on one surface, for example,
Particularly preferred is the laser already proposed by the present applicant in Japanese Patent Application No. 60-270509.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail by way of embodiments with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view of a hybrid optoelectronic integrated circuit according to the present invention, which basically consists of a GaAs FET electronic element 2 on a semi-insulating semiconductor (GaAs) substrate 1, an A I GaAs layer. It consists of an optical waveguide 3 and a semiconductor laser light emitting element 4. In addition, in FIG. 1, an MSM type photodetector 5 that detects the light of the optical waveguide 3
is provided.

The optoelectronic integrated circuit according to the present invention is manufactured, for example, as follows.

First, a semi-insulating semiconductor (Al6.asGao, 5
sAs) Non-doped A1゜, zGa on substrate 1
6. The aAs layer and the GaAs layer are successively epitaxially grown.

For the MSN photodetector 5, a part of the GaAs layer is diagonally etched so as to become thinner little by little as shown in FIG. For this selective oblique etching of the GaAs layer, the surface portion of the GaAs layer to be etched is exposed, and the entire other surface is covered with a photoresist mask layer.
Bost baking is performed at about 200° C. to soften the resist of the photoresist mask layer and round the edges of the mask layer due to surface tension. Using this mask layer as a mask, the exposed portion of the GaAs layer is etched by ion milling (using Ar" ions). At this time, the ions are made to collide with the substrate at an angle of 80 to 70 degrees. Then, the substrate is rotated. As a result of this etching, the GaAs layer can have a gentle slope.The photoresist mask layer is then removed.

The GaAs layer is then selectively etched by a suitable etching method to leave a GaAs portion 8 for the GaAs FET 2 and a GaAs portion 9 with a slope for the MSM photodetector 5. Furthermore, by using an etching method using different etchants and resist patterns, the non-doped A I GaAs layer is selectively etched to form the optical waveguide 3 (including under the GaAs portion 9 for the MSM photodetector 5) and the GaAs portion 8 of the GaAs FET 2. Leaving the A I GaAs section 10 underneath. As shown in FIG. 1, the ^It GaAs portion 10 and the GaAs portion 8 of the GaAs FET 2 are formed in the form of islands on the A I GaAs group vi,1. This GaAs portion 8 is subjected to a known GaAs FET manufacturing process to form a source region, a drain region, a source electrode 11, a drain electrode 12, and a gate electrode 13, and predetermined wirings 14 to 17 are formed to complete the FET. Manufacture. When forming this wiring, MS
The electrode wiring 18 of the M photodetector 5 is formed to become a photodetector. In this case, the light from the optical waveguide 3 leaks into the GaAs portion 9 to generate holes and electrons, and a voltage is applied to the electrode in advance and the light is converted into an electrical signal as the current changes. Further, the ends of the wirings 14 and 15 near the optical waveguide 3 are striped pads parallel to the optical waveguide 3, and correspond to the n-electrodes 21 and n-electrodes 22 of the semiconductor laser (light emitting device) 4, which will be described later. The connection is made using the flip-chip bonding method.

The semiconductor laser 4 is manufactured separately, and the horizontal injection type laser proposed by the present applicant is manufactured as a flip chip. This lateral injection laser basically consists of a semi-insulating GaAs substrate 23, a high-resistance ^It GaAs cladding layer, a multiple quantum well (MQ■ active layer, a high-resistance A II Ga
It consists of an As cladding layer, a non-doped GaAs cap layer, an n-electrode 21, and an n-electrode 22, and a p-type head region 24 and an n-type region 2 sandwiching the light emitting region of the active layer in the lateral direction.
5 is formed, and a p-type contact region 26 and an n-type contact region 27 are formed to allow current to flow laterally through the light emitting region of the active layer. Then, in order to allow the light from this semiconductor laser 4 to pass through the optical waveguide, the electrode-side cladding layer above the light-emitting area is selectively etched to make it a little thinner (about 0.7 μm thick). As a result, the optical closing effect decreases. Incidentally, when there is no need for light emission from the end face, high reflection coating films (not shown) are formed on both sides of the laser end face to achieve laser image formation.

The obtained semiconductor laser 4 is connected to wirings 14 and 15 by face-down bonding so as to straddle the optical waveguide 3, as shown in FIG. At this time, in order to ensure that the light from the laser 4 bleeds into the optical waveguide 3, an adhesive (
For example, Lensbond (trade name) 28 is used. In this way, the semiconductor laser (light emitting element) 4 and the optical waveguide 3 can be optically connected. Furthermore, the optical waveguide 3
A signal light 29 can be input into the optical connector using a known optical connector.

As described above, an optoelectronic integrated circuit can be obtained in which an electronic element and an optical waveguide are monolithically formed on the same semiconductor substrate, and a light emitting element is hybrid-integrated instead of by wire bonding.

Although GaAs is used in the above case, similar optoelectronic integrated circuits made of InP-based materials can also be fabricated.

〔Effect of the invention〕

According to the present invention, an optoelectronic integrated circuit can be obtained through a relatively simple manufacturing process by employing a hybrid method, and the system can be made smaller and more reliable than a configuration made of individual components.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a hybrid optoelectronic integrated circuit according to the present invention. DESCRIPTION OF SYMBOLS 1... Semi-insulating semiconductor substrate, 2... Electronic element (GaAs FET), 3... Optical waveguide, 4... Light emitting element (semiconductor laser), 8, 9-GaAs portion, 14-17. ...Wiring, 21...p electrode, 2
2...n electrode.

Claims (1)

[Claims] 1. A semi-insulating semiconductor substrate, an optical waveguide formed on the semiconductor substrate, an electronic device formed on the semiconductor substrate, and a flip-chip type semiconductor light emitting device. The semiconductor light emitting device is face-down bonded to the semiconductor substrate so as to straddle the optical waveguide,
A hybrid optoelectronic integrated circuit characterized in that the semiconductor light emitting device and the optical waveguide are optically coupled. 2. The hybrid opto-electronic integrated circuit according to claim 1, wherein the semiconductor light emitting device is a lateral injection type laser.