JPH09148548A - Waveguide type semiconductor integrated circuit and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated circuit device of low cost which has both transmitting function and receiving function of an optical signal used in two-way optical communication. SOLUTION: A photodiode region 150 and a light emitting region 170 are cascaded on the same surface of a substrate 10, and an isolation region 160 is formed between the regions. An MQW(multiple quantum well) active layer 40a is not formed in the photodiode region 150 and the isolation region 160. An absorption layer 20a of the photodiode region 150 and a guide layer 20b of an isolation region 160 are bulk layers. The light emitting region 170 consists of a lower side bulk light confinement layer 20c, the MQW active layer 40a and an upper side bulk light confinement layer 50a. The absorption layer 20a, the guide layer 20b and the lower side light confinement layer 20c in the light emitting layer 170 constitute a common bulk layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type semiconductor integrated circuit in which elements having light receiving and emitting functions are integrated on the same substrate and a method for manufacturing the same.

[0002]

2. Description of the Related Art At present, optical fiber communication networks are spread all over the world, and many basic information transmissions are carried out by optical communication. In the future, by the first half of the 21st century, optical fibers will be extended to each home, and video-on-demand and television shopping will be carried out through home terminals that can interactively exchange large amounts of information such as image information. The arrival of the so-called multimedia era is predicted.

In the two-way optical communication service in the multimedia age, optical transmission / reception used as a home terminal
It is desired that the terminal device having the receiving function also be inexpensive. Therefore, what is required is to provide a low-cost semiconductor device having light receiving and transmitting functions.

Recently, an optical device having a function of receiving and emitting light and in which light is emitted and incident on one end face, and a manufacturing method thereof, is characterized by a small number of crystal growth times. Is being researched. The techniques disclosed in the following two documents are typical ones.

Reference 1: Susaki et al. "Improving the wavelength characteristic of the light-receiving sensitivity of a transmission / reception LD" Proceedings of the Japan Society of Applied Physics 29p-ZG-9, 199
5th Spring Reference 2: Takeuchi et al. “Optical integrated device for bidirectional WDM communication [III]
~ Transmitting and receiving elements by bandgap growth control "Proceedings of the Institute of Electronics, Information and Communication Engineers C-211, Autumn 1995 First, the conventional technique disclosed in Document 1 (hereinafter referred to as the first conventional example) will be described.

FIG. 5 is a schematic view showing a transmitting / receiving element which is a first conventional example. In the functional region on the front side of the chip, the multiple quantum well (Q
The W) layer 11 is provided with the bulk absorption layer 2 for light reception, and constitutes a laser diode (LD). In this example, the light-emitting and light-receiving electrodes 3 are also used, and only one is formed.

The manufacturing process will be briefly described. First n-
As the first crystal growth on the InP semiconductor substrate 10, the SCH layer 12, the QW layer 11, the SCH layer 13, and the In layer are formed.
An etching stop layer 4 of P and a bulk absorption layer 2 of InGaAsP are sequentially grown. Next, the bulk absorption layer 2 is partially removed by etching by photolithography. Next, a second crystal growth, the cladding layer of p-InP 5, p ⁺ _- sequentially growing a contact layer 6 of IotanGaAs. Next, after forming the mesa stripe, both sides of the mesa stripe are filled with the Fe-InP burying layer 7. Next, the electrode 3 is formed, and if necessary, the back surface of the substrate is polished or etched to form the lower electrode 8. Finally,
The device of FIG. 5 is completed by forming it into a chip having an appropriate size and providing an antireflection film on the end face of the optical waveguide.

In this manufacturing process, the optical waveguide is formed by one crystal growth, and the number of crystal growth can be reduced. Therefore, it is an object of the present invention to provide a low-priced light receiving and emitting waveguide type semiconductor device by shortening the time in the manufacturing process, saving the raw material gas, and improving the yield. It shares the purpose with examples.

Next, the conventional technique disclosed in Document 2 (hereinafter referred to as the second conventional example) will be described. FIG.
FIG. 6 is a schematic diagram showing a transmitting / receiving element which is a second conventional example. This device comprises a semiconductor laser 15,
The photodiode 16, the directional coupler 17, and the optical waveguide 18 are formed. The active layer in the laser region,
The absorption layer in the photodiode region and the guide layers in the Y branch region and the optical waveguide region may be collectively referred to as an optical waveguide layer hereinafter. The optical waveguide layer in each region is formed by one crystal growth.

The manufacturing process will be briefly described. First, change the mask width on the semiconductor substrate according to each element region,
A pair of masks for preventing crystal growth are formed in the waveguide direction. Next, as the first crystal growth, a multiple quantum well layer and an InP clad layer are sequentially grown. Next, the edges of the pair of masks are etched by photolithography. Next, a second crystal growth, p _- cladding layer of InP, p ⁺ _- sequentially growing a contact layer IotanGaAs. Next, an electrode is formed, and the back surface of the substrate is polished or etched to form an electrode below the surface. Finally, the device of FIG. 6 is completed by forming it into a chip having an appropriate size and providing an antireflection film 19 on the end face of the optical waveguide. However, the contact layer is removed where it is not necessary, such as the optical waveguide portion.

Also in this manufacturing process, the optical waveguide layer in each region is formed by one crystal growth. In other words, in order to create a circuit device having many types of element regions on the same substrate, it is possible to create a circuit device with a butt joint (butt joint) method that has been conventionally performed,
The number of crystal growth can be reduced. Therefore,
The manufacturing process of the second conventional example, which aims to provide a low-priced light receiving and emitting waveguide type semiconductor device by shortening the time in each manufacturing process, saving the raw material gas, and improving the yield, is the same as that of the present invention described later. It has the purpose of.

[0012]

However, the above-mentioned first and second conventional waveguide type semiconductor integrated circuits and the manufacturing method thereof have the following problems.

First, in the first conventional example, the injection of a current into the light emitting functional region and the extraction of the photocurrent from the light receiving functional region are performed by the same single electrode. In general, when a current is injected to function as a light emitting element, it is necessary to insert a terminating resistor in series for impedance matching at high frequency. Also, when a reverse bias voltage is applied to function as a photodiode, terminating resistors are used in parallel for impedance matching at high frequencies. Therefore, as a first problem, in order to use the waveguide type semiconductor integrated circuit for each purpose, a selection means for switching the terminating resistance between series and parallel is required.

Further, in the conventional waveguide type semiconductor integrated circuit, since the light absorption layer in the light receiving function region has a double structure of the bulk absorption layer and the MQW layer, the strength of the electric field applied thereto is
That is, the value obtained by dividing the applied voltage by the total thickness of the non-dope layer is reduced by the thickness of the MQW layer. Therefore, as a second problem, the applied voltage required for sweeping out the photo carriers caused by light absorption becomes large.

Similarly, since the MQW layer exists in the light receiving functional region, carriers are trapped in the well region,
A third problem is that the carrier sweeping time becomes long.

In the second conventional method of manufacturing a waveguide type semiconductor integrated circuit, the MQW structure is adopted for the optical waveguide layer.
In this method, the width of the well layer is controlled by changing the width of the pair of masks, and the bandgap wavelength of the optical waveguide layer in each region is controlled to a desired wavelength. Therefore, the optical waveguide layer in the entire region still has the ΜQW structure, and the difference in the transmission characteristics with respect to the polarization is large. Moreover, the polarization state of the light propagating in the optical fiber changes randomly. Therefore, when the information (hereinafter, abbreviated as an optical signal) that reaches the waveguide type semiconductor integrated circuit is converted into an electric signal by a photodiode through an optical waveguide and a directional coupler, a photo having a QW structure is obtained. Reflecting the polarization dependence of absorption of the diode, the magnitude of the electric current of the converted electric signal changes irregularly. Therefore, as the fourth problem, a code error of the optical signal occurs.

The present invention has been made in order to solve the above-mentioned problems, and a first object thereof is to provide a low cost which has a function of transmitting / receiving an optical signal used particularly in bidirectional optical communication. To provide a waveguide type semiconductor integrated circuit.

A second object of the present invention is a low-cost waveguide in which the active layer in the light emitting region has a ΜQW structure and the optical waveguide layer in the light receiving region and the isolation region between them is composed of only bulk layers. To provide a method for manufacturing a semiconductor integrated circuit.

[0019]

The invention according to claim 1 is
In a waveguide type semiconductor integrated circuit including a light receiving part and a light emitting part, at least the optical waveguide layer region of the light emitting part formed of a quantum well layer having a bulk optical confinement layer on the lower side and the optical waveguide layer region of the light emitting part are formed. The lower optical confinement layer and the optical waveguide layer region other than the light emitting portion formed as a common bulk layer are provided.

A waveguide type semiconductor integrated circuit according to a second aspect of the present invention is characterized in that, in the first aspect, the common bulk layer has a different thickness or composition for each region.

According to a third aspect of the present invention, in the method of manufacturing an integrated circuit having the structure according to the first aspect or the second aspect, a mask is selectively formed in each of the regions, and the common mask is formed. Is characterized in that the bulk layer of is crystal-grown.

A method of manufacturing a waveguide type semiconductor integrated circuit according to claim 4 is the method of manufacturing according to claim 3, wherein the quantum well layer serving as the light emitting portion is grown once on the bulk layer. It is characterized in that the quantum well layers which are simultaneously formed by the above method and are formed in regions other than the light emitting portion are selectively removed by etching.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described.

First Embodiment FIG. 1 is a diagram showing a layer structure of a waveguide type semiconductor integrated circuit according to a first embodiment of the present invention. In the n-nP semiconductor substrate 10, a photodiode region (PD) 150,
A light emitting region (LD) 170 is connected in cascade on the same substrate surface, and a separation region 160 between them is formed. The length of each of the regions 150, 160 and 170 is 50 μm in order.
m, 30 μm and 400 μm. The ΜQW active layer 40a is provided only in the light emitting region 170, and is not provided in the photodiode region and the isolation region. The absorption layer 20a of the photodiode region 150 has a composition wavelength of 1.28 μm and a thickness of 0.25 μm.
The InGaAsP layer and the guide layer 20b of the isolation region 160 are InGaAsP layers having a composition wavelength of 1.28 μm and a thickness of 0.25 μm, both of which are bulk layers. The light emitting region 170 is a lower bulk optical confinement layer (composition wavelength: 1.24) of ΙnGaAsP.
μm, thickness 0.14 μm) 20 c, MQA active layer of InGaAsP (composition wavelength 1.35 μm, number of layers 5) 40 a, and InGaAs
Upper bulk light confinement layer of P (composition wavelength 1.15 μm, thickness
0.1 μm) 50a. The absorption layer 20a, the guide layer 20b, and the light emitting region 170 are formed.
The lower optical confinement layer 20c forms a common bulk layer.

An InP etching stop layer 30 is provided between the ΜQW active layer 40a and the lower optical confinement layer 20c in the light emitting region 170. Then, the optical waveguide layers 20a, 20
b, and the upper portion of the 20c, p _- InP cladding layer 80 and p ⁺ _- ΙnGaAs contact layer 90a, 90b are sequentially formed. Although not shown here, a layer for confining an optical signal and a current (hereinafter, referred to as a lateral direction) on both sides of the optical waveguide layers 20a, 20b, and 20c in a direction perpendicular to the plane of the paper (hereinafter, referred to as a lateral direction). (Abbreviated as a block layer) is formed. Further, electrodes 110 and 120 for injecting current and applying an electric field are formed in the photodiode region 150 and the light emitting region 170, respectively, and a common electrode 130 is formed under the substrate 10. Has been done.
An antireflection film 140 is formed on the end surface on the photodiode region 150 side.

Next, the operation of the waveguide type semiconductor integrated circuit having the above structure will be described.

First, let us consider a case where the optical signal is used for receiving an optical signal. When the optical signal transmitted by the optical fiber enters the end face on the photodiode region 150 side, the optical signal is absorbed by the absorption layer 20a in the photodiode region. At this time, if a reverse bias voltage of several V is applied to the absorption layer 20a, light having a wavelength longer than the bandgap wavelength (composition wavelength) of the absorption layer is also absorbed by the electric field absorption effect. Further, since an electric field is applied here, carriers generated by light absorption are efficiently swept out.
Generally, for incident light having a wavelength shorter than the bandgap wavelength of the absorption layer, the absorption coefficient of light is 1000 [cm ^-1 ] or more. Therefore, if the absorption layer absorbs 99% or more of light, the length of about 50 [μm] is sufficient for sufficient absorption. Also, for incident light with a wavelength longer than the bandgap wavelength, if the difference is about 100 nm or less, the reverse bias voltage of several V is applied to make the absorption coefficient of light in the absorption layer 1000. In order to be about [cm ^-1 ],
Sufficient light absorption can be realized with a length of about 50 [μm], and it is surely converted into an electric signal.

Next, consider the case of using for transmitting an optical signal. When a current is injected into the light emitting region 170, light emission occurs at a wavelength near the bandgap wavelength of the active layer 40a or a wavelength shorter than that due to the stimulated emission effect. At this time, if the stimulated emission gain due to current injection becomes larger than the sum of the transmission loss at the end face on the photodiode side and the end face on the light emitting part side and the optical loss due to absorption and scattering inside the element, laser oscillation occurs. In the first embodiment, the bandgap wavelength of the active layer 40a is 100 times shorter than the bandgap wavelength of the lower optical confinement layer 20c.
Since it is longer than [nm], there is no excessive absorption loss in the light emitting part.
The difference in bandgap wavelength between the active layer 40a and the absorption layer 20a or the difference in bandgap wavelength between the active layer 40a and the guide layer 20b is 100 [nm] or less. The length of 20b is 50-30
Since it is as short as μm, if no voltage is applied to the photodiode region 150 or a forward bias is applied, the stimulated emission light generated in the light emitting portion is hardly absorbed and is output as an optical signal.

The first embodiment has the following effects a and b when compared with the first conventional example.

A. Since the photodiode region 150 and the light emitting region 170 are formed as separate regions, the terminating resistors for high frequency impedance matching can be mounted in parallel or in series depending on the respective regions.

B. Since the light absorption layer is only the bulk layer,
The applied voltage is applied only to the absorption layer, and therefore, the voltage required for sweeping out the photo carriers caused by light absorption can be reduced. Further, the photo carriers generated by light absorption are swept out without being trapped.

Second Embodiment Next, an example of a method of manufacturing the waveguide type semiconductor integrated circuit described in the first embodiment will be described with reference to FIG.

First, on the n-InP semiconductor substrate 10, the width is
A first SiO ₂ mask 210 having a width of 40 μm is formed on both sides of a portion of the photodiode region of 20 μm where an absorption layer is to be grown (hereinafter referred to as absorption layer growth region 200) (FIG. 2A). The width of the absorption layer growth region 200 determines the width of the optical waveguide, which is usually about 3 to 30 μm.

Next, as the first crystal growth, the ΙnGaAsP bulk layer 20 and the InP are formed on the entire exposed portion of the upper surface of the substrate 10 by a metal organic chemical vapor deposition method (hereinafter abbreviated as MOVPE).
Layer 30, InGaAsP / InGaAs As QW active layer 40,
And the InGaAsP bulk layer 50 are sequentially formed (FIG. 2B).

Next, a second S
An iO ₂ mask 220 is formed. Then, the region not masked by the second mask 220 is etched down to the etching stop layer 30 using a selective etchant (FIG. 2C).

Next, after removing both the first mask 210 and the second mask 220, a stripe-shaped third SiO ₂ mask 230 is formed. After that, the third mask 2 is formed by dry etching or wet etching.
The portions not masked by 30 are etched to form mesa stripes (FIG. 2D).

Next, as the second crystal growth, the semi-insulating InP layer 60 and the n _-- InP layer 70, which are the block layers, are embedded on both sides of the mesa stripe. Furthermore, after removing the third mask 230, the entire surface p as third crystal growth _- InP cladding layer 80 and p ⁺ _- regrowing InGaAs contact layer 90 (FIG. 2 (e)).

[0038] Finally, in order to make the electrical insulation of the light emitting region and the photodiode area and perfect, p ⁺ _- ΙnGaA
The s contact layer 90 is partially etched to form electrodes 110 and 120 in the respective regions. Further, the back side of the substrate is removed by etching or polishing until the thickness is such that chips can be formed by cleavage, and the common electrode 130 is formed in the entire area of the back side. After that, the chip is made to have an appropriate size, and the antireflection film 140 is formed in the photodiode region to complete the waveguide type semiconductor integrated circuit (FIG. 2F).

In the semiconductor device manufactured in this way, 1
The optical waveguide layer in the light emitting region and the isolation region without the first SiO ₂ mask 210 in the ΙnGaAsP bulk layer 20 in the second crystal growth is the optical waveguide layer in the photodiode region formed by the first SiO ₂ mask 210. Is different in its thickness and composition.

FIG. 3 is a diagram for explaining the growing thickness (growth thickness) of the optical waveguide layer and its composition wavelength. Here, the horizontal axis is the SiO ₂ mask width Wm, and the left and right vertical axes are the values obtained by dividing the growth thickness in the region sandwiched between the SiO ₂ masks by the growth thickness in the region without the mask (normal). of thickness), the value obtained by subtracting the band gap energy of the area without SiO ₂ mask from the band gap energy of the region between the SiO ₂ mask (energy difference ΔE
[meV]) is shown. However, in this measurement, Si
With the width of the absorption layer growth region 200 sandwiched between the O ₂ masks 210 fixed at 20 μm, the InG
Crystals of aAsP were grown. The band gap wavelength in the region without the SiO ₂ mask was about 1.3 μm.

[0041] As can be seen from Figure 3, in the region between the SiO ₂ mask, increasing the SiO ₂ mask width Wm, growth thickness increases, also the band gap energy is made can be seen that small. This is mainly due to the influence of diffusion of In and Ga (migration of group III atoms) on the SiO ₂ mask. Therefore, when the SiO ₂ mask width Wm is set to 40 μm as in this embodiment, the photodiode region 150 sandwiched by the mask is formed.
In comparison with the optical waveguide layer in the isolation region 160, the thickness of the lower optical confinement layer 20c in the light emitting region 170 can be formed as thin as about 58%. In addition, the light emitting area 170
The bandgap energy of the lower optical confinement layer 20c in the
From the bandgap energy of the optical waveguide layer at 0
It becomes 30 meV larger.

According to the manufacturing method of the second embodiment, the following effect c can be realized.

C. The effects a and b pointed out in the first embodiment can be realized by the method of combining the selective region growth and the selective etching of the active layer.
Moreover, the photodiode region 150 and the isolation region 160
Can be independently designed while using the optical waveguide layer as a bulk layer and adopting the QW structure as the active layer.

That is, the lower optical confinement layer 20c below the active layer of the light emitting region 170 is the photodiode region 150.
Although it is formed as a layer common to the optical waveguide layer of the isolation region 160, the lower optical confinement layer can be grown by controlling the thickness to a thickness suitable for the optical confinement layer in the light emitting region by growing the selective region. Therefore, the active layer grown on that layer is a layer different from the bulk layer commonly formed in each region, so that independent design values can be selected. On the other hand, in the first conventional example, even if the second problem of the conventional technique can be solved by electrically separating the portion with the bulk absorption layer and the portion without the bulk absorption layer, the thickness of the bulk layer still remains. If the thickness is made too thick, the supersaturated absorption characteristic becomes prominent in the vicinity of the threshold value, and if it is made too thin, the effect of providing that layer is lost.

Third Embodiment FIG. 4 is a diagram showing a layer structure of a waveguide type semiconductor integrated circuit according to a third embodiment of the present invention. On the n-InP semiconductor substrate 510, a Y branch region 650 including the vicinity of the input / output end face of an optical signal, a photodiode region (PD) 660 on one side of the branch waveguide and a light emitting region (L on the other side).
D) 670 is formed on the same substrate via the isolation region 680 that connects these regions and performs electrical isolation.

FIGS. 9B to 9E show cross sections B to E in FIG. 9A. Photodiode region 66
0 InGaAsP absorption layer 520a and Y branch region 650
And the n-GaAsP guide layer 520b of the isolation region 680
Are both bulk layers. In the light emitting region 670, grating processing is performed on the substrate, and InGaA is formed on the grating processing.
A lower bulk light confinement layer 520c of sP, an InGaAsP QW active layer 540a, and an upper bulk light confinement layer 550a of InGaAsP are sequentially formed. further,
The absorption layer 520a and the guide layer 520b and the lower optical confinement layer 520c of the light emitting region 670 form a common bulk layer.

Between the ΜQW active layer 540a and the lower optical confinement layer 520c of the light emitting region 670, there is a ΙnP etching stop layer 530. Then, on top of the optical waveguide layer, p _- InP cladding layer 580 and p ⁺ _- ΙnGaA
s contact layer 590 is sequentially formed. Also,
Similar to the first embodiment, block layers 560 and 570 are formed at lateral positions of the optical waveguide layer. Electrodes 610 and 620 for injecting current and applying an electric field are formed in the photodiode region 660 and the light emitting region 670, and the common electrode 630 is provided below the substrate 510.
Are formed. An antireflection film 640 is formed on the end face on the Y branch region 650 side.

Next, the operation of the waveguide type semiconductor integrated circuit having the above configuration will be described.

First, let us consider a case in which it is used for receiving an optical signal. The optical signal transmitted through the optical fiber is the Y branch area 65.
When incident from the 0-side end face, half the power of the optical signal is guided to the photodiode region 660 by the Y branch region 650 and is absorbed by the absorption layer 520a. At this time, if a reverse bias voltage of several V is applied to the absorption layer 520a, light having a wavelength longer than the bandgap wavelength of the absorption layer is also absorbed by the electric field absorption effect. Further, since an electric field is applied, carriers generated by light absorption are efficiently swept out. These operations are similar to those of the device according to the first embodiment.

Next, consider the case of using for transmitting an optical signal. When a current is injected into the light emitting region 670, light emission occurs at a wavelength near the bandgap wavelength of the active layer 540a or a wavelength shorter than that due to the stimulated emission effect. Here, a feedback action of light occurs due to the grating processing on the substrate, and a DFB (distributed feedback type) laser structure that oscillates a laser when a certain current is exceeded is formed. Further, similarly to the description of the operation in the first embodiment, the active layer 540a and the lower optical confinement layer 520 are formed.
Since the difference in bandgap wavelength from c is 100 [nm] (0.1 μm) or more, there is no excessive absorption loss in the light emitting portion. The oscillated optical signal is guided through the separation region 680 and the Y branch region 650, and is extracted from the end face to the outside.

According to the third embodiment, the following effects d and e can be realized.

D. Compared with the second conventional example, the optical waveguide layer on the path from the end face where the optical signal enters and exits to the photodiode region 660 does not have the ΜQW layer, and is formed of only the bulk layer. Therefore, the polarization independence required for the optical signal receiving operation can be realized. Further, the effects a and b of the first embodiment are also achieved at the same time.

The method of manufacturing the circuit shown in the third embodiment can be easily understood from the analogy of the manufacturing method shown in the second embodiment. , The following points.

E. A bulk layer can be adopted for the optical waveguide layers of the photodiode region 660 and the isolation region 680 while adopting the ΜQW structure for the active layer, and they can be designed independently. Regarding the degree of independent design, it is better to apply to the second conventional example than to the first conventional example.
Has a greater effect.

In the description of the first, second and third embodiments, the present invention is simply shown to the extent that the present invention can be implemented. Therefore, the present invention is not limited to the specific numerical values and materials pointed out in the above description, and is not limited to the lateral embedded structure. As the optical element structure of the waveguide type semiconductor integrated circuit, for example, if a high-mesa ridge type waveguide structure is adopted for the stripe of the optical waveguide layer, the number of crystal growth can be further reduced. Also, when using another semiconductor crystal substrate such as a GaAs substrate without using the InP semiconductor substrate,
A similar effect can be obtained.

That is, the present invention is an element that can be formed at least by a step of growing a plurality of optical waveguide layers at a time, and the thickness or composition of the optical waveguide layers differ depending on the waveguide direction, and The element can be applied to any type as long as it includes an element common to the above.

In the first embodiment, no grating structure is provided inside or outside the light emitting region (particularly on the separation region side). That is, the light emitting unit is L
The element that functions as an ED or FP (Fabry-Perot) laser has been described. However, a DFB (Distributed Feedback Type) laser or D
Naturally, it may be operated as a BR (distributed reflection type) laser.

Similarly, also in the third embodiment, a DBR laser structure may be provided by providing a grating structure outside the light emitting region, particularly on the side of the isolation region, or an LED or FP type resonance mode without a grating structure. May be operated as a laser.

Further, in the manufacturing method of the second embodiment,
The second SiO ₂ mask is formed, and the unmasked region is etched up to the etching stop layer by using a selective etchant. However, the etching stop layer may be etched or left as it is. Good.

[0060]

Since the present invention is configured as described above, it is a low-cost and excellent waveguide type semiconductor integrated circuit which has a function of transmitting / receiving an optical signal used in bidirectional optical communication. Can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a layer structure of a waveguide type semiconductor integrated circuit according to a first embodiment of the present invention.

FIG. 2 is a process explanatory view showing an example of a method of manufacturing a waveguide type semiconductor integrated circuit of the present invention.

FIG. 3 is a diagram illustrating a growth thickness of an optical waveguide layer and its composition wavelength.

FIG. 4 is a diagram showing a layer structure of a waveguide type semiconductor integrated circuit according to a third embodiment of the present invention.

FIG. 5 is a schematic diagram showing an example of a transmission / reception element according to a conventional technique.

FIG. 6 is a schematic diagram showing another example of a transmission / reception element according to a conventional technique.

[Explanation of symbols]

10 substrate, 20 optical waveguide layer, 30 etching stop layer, 40a active layer, 50a confinement layer, 150
Photodiode area, 160 isolation area, 170 light emitting area.

Claims (4)

[Claims] 1. A waveguide-type semiconductor integrated circuit including a light-receiving portion and a light-emitting portion, comprising: an optical waveguide layer region of the light-emitting portion, which is formed of a quantum well layer having a bulk optical confinement layer at least on the lower side; A waveguide-type semiconductor integrated circuit, comprising: a lower optical confinement layer of the optical waveguide layer region; and an optical waveguide layer region other than the light emitting portion formed as a common bulk layer. 2. The common bulk layer has a different thickness or composition for each region.
2. A waveguide type semiconductor integrated circuit as set forth in. 3. A method of manufacturing an integrated circuit having the structure according to claim 1 or 2, wherein a mask is selectively formed in each of the regions to crystallize the common bulk layer. A method of manufacturing a waveguide type semiconductor integrated circuit, comprising: 4. The quantum well layer to be the light emitting portion is simultaneously formed on the bulk layer by one-time crystal growth, and the quantum well layer formed in a region other than the light emitting portion is selectively removed by etching. The method for manufacturing a waveguide type semiconductor integrated circuit according to claim 3, wherein