JPS6356955A - Optoelectronic integrated circuit device - Google Patents

Abstract

PURPOSE:To produce an optoelectronic integrated circuit device (OEIC) capable of responding rapidly by means of simple manufacturing processes, by monolithically integrating a lateral injection laser having an active layer of a quantum well structure and a field-effect transistor (FET). CONSTITUTION:A semiconductor laser comprises an active layer 11 having a quantum well structure, insulating or semi-insulating clad layers 7, 8 sandwitching the active layer and P-type and N-type regions 1, 2 spaced from each other and formed by introducing a conducting dopant into the active layer through the clad layer. Disordered regions 1A, 2A are formed by the phenomenon that GaAs and A GaAs are diffused in each other to provide a disordered state in which mixed crystals with averaged composition are produced. The active layer thereby provides a lateral double-hetero structure improving the lateral containment of light. In an FET, a gate electrode 5 is formed on the active layer which serves as an operating region.

Description

[Detailed Description of the Invention] [Summary] A lateral injection laser and a field effect transistor (FET) with a quantum well structure as an active layer are monolithically integrated,
Achieving an optical/electronic integrated circuit device (OEIC) capable of rapid response using a simple manufacturing process.

[Industrial application field]

The present invention relates to a lateral injection laser having a quantum well structure as an active layer and an OBIC structure in which FETs are integrated.

0BIC is a semiconductor device that integrates a light-emitting element such as a laser, or a light-receiving element such as a photodiode, and an electronic element such as an FET on the same substrate, and has attracted attention as a device for optical communication, and its technology has been actively developed in recent years. It is being done.

The present inventor previously filed a patent application for a lateral injection laser in which the active layer is a quantum well structure that improves the lateral confinement effect of light, reduces the threshold current, and is suitable for integration. 2
Although disclosed in the specification of No. 7059, the present invention proposes an 0EIC structure in which this laser is integrated.

[Conventional technology]

In the conventional technology, when the laser element thickness is large and the laser and electronic elements are integrated, in order to realize planarization, a groove is dug in the substrate in advance and the semiconductor laminated structure that makes up the laser is embedded. It had become For this reason, the manufacturing process was extremely complicated.

Furthermore, since the laser current was injected perpendicularly into the active layer, it was difficult to take out the electrodes during integration.

FIG. 5 is a sectional view of a laser forming part of an OBIC according to a conventional example.

In the figure, 51 is a semi-insulating (ST)-GaAs W plate, 52 is a laser semiconductor laminated structure, 53 is an n-side electrode, 5
4 is a p-side electrode.

Although the FET is not shown, the 5r-GaAs substrate 51
It is formed on the flat part of the surface.

If the laser is formed in the groove dug in the substrate in this way, the laser and the surface of the substrate can be formed at the same height, but the difference in level caused by the groove makes it difficult to form electrodes and wiring layers.

FIG. 6 is a sectional view of a laser forming part of an 0EIC according to another conventional example.

In this case, instead of forming a groove in the 5l-GaAs % plate 51, the semiconductor laminated structure 52 of the laser is simply laminated on the substrate, making it even more difficult to take out the electrodes.

[Problem that the invention seeks to solve]

In the conventional 0EIC, planarization and electrode extraction, which are important requirements for integration, are difficult. Also,
Since the integrated laser is a normal vertical injection laser, its high-speed response is poor.

[Means for solving problems]

The solution to the above problem is to have an active layer with a quantum well structure, a cladding layer of insulating or semi-insulating semiconductor layers sandwiching the active layer, and a conductive impurity that is inserted into the active layer at intervals through the cladding layer. a semiconductor laser having p-type and n-type regions formed by introducing a semiconductor laser, wherein quantum well structures in the p-type and n-type regions are disordered, and the active layer has a double heterostructure in the lateral direction; A gate electrode is formed on the active layer, and a conductive impurity is introduced into the active layer of the semiconductor layer formed on the cladding layer. An 0EIC including an FET in which a source and a drain are formed electrically connected to the p-type and n-type regions, respectively, and a gate electrode is formed on the active layer between the source and drain regions. achieved.

[Effect]

The present invention allows for a simpler manufacturing process by integrating a lateral injection laser with an active layer having a quantum well structure that can reduce the thickness of the laser element and reduce the interelectrode capacitance with an electronic element such as PET. This realizes 0ETC capable of high-speed response.

〔Example〕

FIG. 1 is a sectional view illustrating an embodiment of the structure of an 0EIC according to the present invention.

The left half of the figure is a lateral injection laser whose active layer is a quantum well structure, and the right half is an FE whose active layer is the same active layer as the laser.
Indicates T.

In the figure, 1 is a p-wall region formed by diffusion of p-type impurity (Zn), IA is a disordered region by n-type diffusion, and 2 is an n'-type region 2A formed by diffusion of n-type impurity (St). A disordered region due to n-type diffusion, 3 is a wiring layer of Au/Ti layer with a thickness of 3000 nm, and 4 is an n-type wiring layer.
Type ohmic contact layer is Au/8u layer, 5 is gate metal, Au/Pt/Ti/41 layer, 7.8
is the cladding layer, which is a high resistance (HR)-AlGaAsxAs layer with a thickness of 1 μm (x = 0.45
), 9 is a groove for element isolation, 10 is a 5l-GaAs base layer, 11 is an active layer of a multiple quantum well (MQW) structure, and 11A is an active layer [light emitting region] of a lateral injection laser, with a width of 0. 5~
1.5 μm 12.13 is an n-type region (MQW) formed by St diffusion.
(when the layer is doped to n-type), or a p-wall region formed by Zn diffusion (when the MQW layer is doped to p-type) [source, drain region].

The disordered regions IA and 2A are regions in which GaAs and GaAs interdiffuse and become disordered, forming a mixed crystal with an average composition.As a result, the active layer forms a double heterostructure in the lateral direction, and This improves light confinement.

Next, the outline of the manufacturing process of the 0EIC of the present invention will be explained.

First, a 5I-GaAs substrate 10 is grown by a molecular beam epitaxial growth (MBE) method, a metal-operated chemical vapor deposition (MOCVD) method, a vapor phase epitaxial growth (VP'E) method, etc.
An HR-AIGaAs cladding layer 3, an active layer 11 having an MQW structure, and an HR-^lGaAs cladding layer 7 are successively grown thereon.

Next, ■ When the MQW layer is doped with n-type, S
i is diffused to form the n-type region 2 and the source and drain regions 12.
13 is formed at the same time, and Zn is further diffused at 600° C. to form a p-type head region 1.

■ When the gate leaf layer is doped with p-type, Si
Zn is diffused to form an n-type region 2, and further Zn is diffused at 600°C.
is diffused to form p-type head region 1 and source and drain regions 12.1.
3 at the same time.

For forming these regions, ion implantation may be used instead of the above-mentioned vapor phase diffusion.

Through the above steps, a lateral injection laser is formed on the substrate.

Next, use normal glue lithography to connect the laser part and FE.
A groove 9 separating the T portions is formed so as to reach the cladding layer, and the cladding layer 7 in the PET formation region is formed to a thickness of 3000 mm.
A recess structure is formed by etching to expose the active layer 11 at the gate formation position.

In this case, the etchant is 182504+8)+20□+lH2O is used.

Alternatively, a CI-based etching gas or active ion etching (RYE) may be used.

Next, Au/Pt/
The Ti/AI layer 5 is coated with Au/AuGeN4 for n-type ohmic contact on the source 7 and drain region 2.13.
is formed to complete the FET.

Next, a wiring layer 3 is formed to make connections between elements and terminals, thereby completing the 0BIC.

FIG. 2 is a distribution diagram of the mixed crystal ratio X of A1gGa+-Js in the thickness direction, illustrating the active layer of the MCIW structure (periodic structure of GaAs/81Gas to s).

In the figure, the MQW has a thickness of 80 mm and a concentration of I x 10"cm-" n-Ga.
5 layers of As1, 120 people thick, concentration I x 10”c!
+1-' AlGaAs (x = 0.3) R to 4
It is formed by stacking layers alternately (in the case where the MQW layer is doped to p-type).

FIG. 3 is a sectional view illustrating another embodiment of the structure of the 0EIC of the present invention.

The lower part of the figure shows a lateral injection laser having a quantum well structure as an active layer, and its configuration is the same as that in FIG.

On top of the laser is an n-GaAs layer 6 with a thickness of 0.25 μm and a width of I x 10” cm as an active layer of PET.
form.

Si is placed so as to reach the n-type region 1 and n-type region 2 of the laser.
is introduced to form n-type source and drain regions 14 and 15.

n-GaAs layer 6 between source and drain regions 14 and 15
A recess structure is formed in the recess structure, and a gate electrode 5 is formed therein, and furthermore, an Au/AuGe layer 4 for an n-type ohmic contact is formed on the source and drain regions 14 and 15.

The above structure constitutes a composite device in which a laser diode (LD) and FET are connected in parallel, and its equivalent circuit is
As shown in the figure.

In this case, when the PET is off, current flows to the LD and emits light, and when the FET is on, the current flows to the FET and stops emitting light. In this way, the emitted light of the laser can be modulated.

〔Effect of the invention〕

As explained in detail above, according to the present invention, there is no need to process the substrate in advance, especially in the case of FIG.
Since the laser layer and PE7 layer can be formed by multiple crystal growth,
The manufacturing process becomes extremely simple.

■ Planar lasers can be realized and electrodes can be formed on the same surface, making integration with electronic devices easier.

■ Since a lateral injection laser with a quantum well structure as the active layer is used, the active layer is sandwiched between high-resistance layers and the p and n electrodes can be formed with extremely small volumes, resulting in extremely small electrode capacitance and high speed. 0BIC will be realized.

■ The present invention can be applied to all materials that can form an MQW structure.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view illustrating an example of the structure of 0BIC of the present invention, and Fig. 2 is a cross-sectional view illustrating an active layer of an MQW structure (periodic structure of GaAs/AlGaAs), showing a mixed crystal ratio X of AlXGa+-,^S. 3 is a cross-sectional view illustrating another embodiment of the structure of the 0EIC of the present invention, FIG. 4 is an equivalent circuit diagram of the 0BIC shown in FIG. 3, and FIG. 5 is a conventional example. FIG. 6 is a cross-sectional view of a laser forming portion of an 0EIC according to another conventional example. In the figure, 1 is an n-type region, IA is a disordered region due to p-type diffusion, 2 is an n-type region, 2A is a disordered region due to n-type diffusion, 3 is a wiring layer, which is an Au/Ti layer, and 4 is an n-type Au/Ti layer. mink contact layer to Au/8u e layer, 5 is gate metal to 8u/Pt/Ti/Alq, 6 is active layer to n-GaAs layer, 7.8 is cladding layer to HR-1 GaAs layer 9 10 is a trench for element isolation, 10 is a 5I-GaAs substrate, 11 is an active layer of MQW structure, 11^ is a laser active layer (light emitting region), 12.13 is an n-type region, or an n-type region (source, drain region). ), 14.15 is the n-type region (source, drain region). The tth Ogata-bo Yamaseyama Enji, Figure 5, Haya 614

Claims (2)

[Claims] (1) An active layer with a quantum well structure, a cladding layer of insulating or semi-insulating semiconductor layers sandwiching the active layer, and conductive impurities introduced into the active layer at intervals through the cladding layer. having p-type and n-type regions formed;
The quantum well structures in the type and n-type regions are disordered, and the active layer forms a semiconductor laser having a double heterostructure in the lateral direction, and a gate electrode is formed on the active layer, making the active layer an operating region. An optical/electronic integrated circuit device comprising a field effect transistor. (2) An active layer having a quantum well structure, a cladding layer of an insulating or semi-insulating semiconductor layer sandwiching the active layer, and conductive impurities introduced into the active layer at intervals through the cladding layer. having p-type and n-type regions formed;
The quantum well structures in the type and n-type regions are disordered, and the active layer has a double heterostructure in the lateral direction. Conductive impurities are introduced into the active layer of the semiconductor layer formed on the cladding layer. and forming source and drain regions electrically connected to the p-type and n-type regions, respectively, and forming a gate electrode on the active layer between the source and drain regions. An optical/electronic integrated circuit device characterized by: