JP3421999B2 - Optical functional device, optical integrated device including the same, and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor optical functional device used in the field of optical communication, and more specifically to a plurality of optical functional devices having slightly different emission or reception wavelengths and a method for manufacturing the same. It is a thing. The optical function element includes a light emitting element, an optical waveguide, a light receiving element, a spot size conversion element, a wavelength conversion element, a demultiplexer, a multiplexer, and the like. The semiconductor light emitting device can be applied to a light source for optical measurement, an integrated light source, a variable wavelength light source, a light source for optical communication, etc. by utilizing its wide band property and high directivity. For example, in the field of optical communication, a multi-wavelength integrated light source capable of increasing the capacity of a terabit class, and in the field of optical measurement, fiber gyro and OTDR (O
optical Time-Domain Reflect
It is useful as a light source for tomtry).

Further, the present invention relates to a semiconductor integrated optical device used for optical communication and optical processing such as optical information processing and optical switching. In particular, the present invention relates to an optical integrated device in which a semiconductor device having at least one transmitting / receiving function is integrated on a semiconductor substrate and a method for manufacturing the same.

[0003]

2. Description of the Related Art With the advancement of optical communication systems, a plurality of optical functional elements such as a light emitting element, an optical waveguide, and a light receiving element are arranged on a semiconductor substrate so that a large number of optical communication signals can be collectively processed. Research is progressing. For this,
There is an urgent need to develop an optical functional element capable of processing a plurality of wavelengths having slightly different communication wavelengths, and it is desired to develop a plurality of light emitting elements having slightly different emission wavelengths on a semiconductor substrate.

As a method of changing the oscillation wavelength of the light emitting element, for example, a DFB in which a diffraction grating having a period according to the oscillation wavelength is built in a semiconductor multilayer film having a crystal structure of uniform composition
A method using a (distributed feedback type) laser or a DBR (black reflection type) laser is generally used. However, in this method, the wavelength range in which a single light-emitting element can oscillate is determined by the light-emitting area of the active layer, that is, the gain width, and thus the wavelength variation amount is limited to about 100 nm, and the oscillation characteristics of the light-emitting element also have a wavelength range. It changed depending on the region.

There is also a method of utilizing the temperature dependence of the bandgap of a semiconductor to change the oscillation wavelength with temperature, but this has a slow response, is not suitable for integration, and emits light other than the oscillation wavelength. There are drawbacks such as changes in characteristics.

By the way, in order to slightly change the emission wavelength characteristics of a plurality of light emitting elements arranged in a plane on a semiconductor substrate and the wavelength sensitivity characteristics of a light receiving element, usually, a crystal composition corresponding to each wavelength is used. It is necessary to form a semiconductor layer, and in the conventional semiconductor growth techniques, a plurality of semiconductor layers having slightly different crystal compositions are produced on the same substrate by repeating crystal growth a plurality of times.

Several methods have been proposed or attempted as methods for growing crystals having different emission characteristics on the same substrate, but all of them are decisive techniques that exceed the repetition of growth a plurality of times. Is not.

For example, in order to slightly change the emission wavelengths of a plurality of optical functional elements, the active layer may be slightly changed in width to produce the oxide film having a predetermined active layer width or waveguide width on a semiconductor substrate. A stripe mask made of a film or a nitride film is arranged in advance, and a crystal is grown between the stripe masks (usually called a mask selective growth method. Aoki et al.
Applied Electronic Physics Subcommittee Research Report No. 445, p9-1
There is 4).

FIGS. 1A to 1C are explanatory views of this mask selective growth method, and FIG. 1A shows a stripe-shaped oxide film having a predetermined size on a flat semiconductor substrate 1 or The case where the nitride film 2a is formed is followed by crystal growth of the semiconductor multilayer film. Wm is the width of each stripe, and Wg is the width of the gap between the two stripes 2a. In addition, FIG. 1B shows a semiconductor multilayer film including a buffer layer 5, an active layer width or a waveguide layer 6, a clad layer 7, and a contact layer 10 on the semiconductor substrate of FIG. To form a ridge 3 and a groove 4 on both sides thereof. FIG. 1C shows In _1-x Ga _x As / InGaAsP (λ
(g = 1.15 μm) is a characteristic example showing the relationship between the mask width Wm of the system crystal and the emission wavelength using the groove width Wg as a parameter.

The emission wavelength shift amount increases as the mask width Wm increases, and increases as the gap width Wg decreases. The reason is that the growth rate changes because the raw material diffuses from the mask to the gap, and the change in the thickness of each semiconductor layer on the mesa, especially the quantum well layer, formed on the gap causes a change in the emission characteristics. This is because

However, this crystal growth method cannot avoid the influence of the mask such as the diffusion of impurities from the mask, and the crystallinity is not necessarily good as compared with the case without the mask. Further, the mask must be removed after the crystal growth in the process of progressing the process, and the process becomes complicated.

Further, in order to cause a wavelength shift of about 100 nm, it is necessary to spread the mask by about 100 μm in the lateral direction, so that it cannot be applied to integration in a minute region of about several μm. It should be noted that when the wavelength is largely changed, the position of the light emitting layer in the vertical direction in the cavity direction is displaced, so that the optical coupling is deteriorated.

On the other hand, as a method of slightly changing the crystal composition of the active layer without using a mask to change the emission characteristics, a metal organic molecular beam epitaxy method (MOMBE method) is used, and laser light is emitted during crystal growth. By irradiating
There is a method of changing the light emission characteristics (Yamada et al., Applied Electronic Physics Subcommittee Research Report No. 445, P. 27-32). However, this method has drawbacks such as the need to use a specific and expensive device and the inability to produce crystals having a plurality of compositions varied in a wide range.

Next, a ridge is formed in advance on the semiconductor substrate,
A light emitting device having a semiconductor layer grown thereon will be described.

Using a semiconductor substrate having a plurality of ridge shapes in which the ridge width is slightly changed in advance, a light emitting device in which an active layer of a strained quantum well is formed on the ridge substrate by a molecular beam epitaxy (MBE) method is manufactured. However, it has been reported that a plurality of light emitting elements having slightly different emission wavelengths can be realized (Japanese Patent Laid-Open No. 4-305991).

However, this method utilizes the exciton transition energy of the strained quantum well and has a ridge width of 2 μm.
m, 3 μm, 5 μm, 8 μm, the emission wavelengths are 1.52 μm, 1.53 μm, 1.54 μm, 1.55
However, since the amount of change is small, the controllability of the amount of wavelength shift by only the ridge width is not high.

A method for producing a multi-wavelength laser by changing the ridge width and the ridge groove width has been reported (Japanese Patent Laid-Open No. Hei 4-
No. 364084), the emission wavelength is changed by changing the thickness of the active layer. In addition, a light emitting device in which a semiconductor layer is formed by a metal organic chemical vapor deposition method on a substrate having two types of grooves having different widths on both sides of a ridge has been reported (Japanese Patent Laid-Open No. 4-204).
No. 206982), in which a semiconductor layer having a large band gap is formed at the laser end portion, and the laser with a so-called window structure is aimed at preventing deterioration of the end face and increasing the output.

Further, as a method for broadening the light emission characteristics by growing those having different compositions in the vertical direction, there is a functional super luminescent diode (The Institute of Electronics, Information and Communication Engineers OQE91-83 (1991), Noguchi, etc.). ). In this functional super luminescent diode, the light emitting portions with different compositions are produced by two crystal growths respectively, so in addition to the complexity of the crystal growth, the growth surface between both light emitting portions has a small loss. Ingenuity for growth is also required.

It is possible in principle to manufacture three or more kinds of light emitting regions different from each other, but a very advanced technique is required in terms of crystal growth and processing. Therefore, up to now, there have been almost no examples of light-emitting elements in which three or more kinds having different compositions are vertically integrated.

Conventionally, most optical transceivers with optical amplifiers at each terminal in optical communication are made by combining bulk materials such as demultiplexers, LDs, PDs, etc. Also, a waveguide and a semiconductor formed of quartz or the like are used. The laser and photodetector formed in 1. are connected with solder or the like, or are combined with a fiber or the like. In addition, there is one in which necessary semiconductor components are integrated on one semiconductor substrate.

However, in the case of using the bulk material and the method of using the quartz waveguide, the size of the components becomes large due to the coupling of the respective components through the space, and the adjustment becomes complicated and the manufacturing process is complicated. It is complicated, and it is not suitable for mass production. Also, there was a problem with connectivity. In the case of semiconductor integrated circuits, since semiconductors having various band gaps must be formed on a single semiconductor substrate, a part of the crystal once grown is removed, and a semiconductor with a different composition is grown again. The manufacturing process becomes complicated,
As it requires a very high level of technology, it cannot currently be a viable alternative to combining individual components into a hybrid.

On the other hand, integration of individual semiconductor optical devices is an essential technique for achieving high performance, high functionality, and economy of optical communication and optical information processing systems. In the integration of semiconductor optical devices, individual semiconductor optical devices are connected by glass optical circuits or optical fibers. Even when a plurality of elements are monolithically integrated on the same semiconductor substrate, input / output of optical signals to / from the integrated element is performed via a glass optical circuit or an optical fiber.

The integration of optical devices is different from the integration of electronic devices in that there is a problem of re-coupling loss of light passing between the devices. This is because the light spot size on the semiconductor element side is smaller than the spot size on the glass optical circuit or optical fiber side connected thereto. In order to avoid this and further loosen the connection tolerance, an element has been devised which converts a small spot size on the semiconductor element side into a large spot size on the glass or optical fiber side.

When the spot size conversion of the optical element is performed by the optical waveguide, a structure in which at least one of the thickness, the width, and the refractive index difference between the waveguide core and the clad is changed along the optical waveguide direction. Must be formed. The semiconductor waveguide structure is usually manufactured by processing the epitaxial growth layer by a method such as dry etching and further performing epitaxial regrowth. Therefore, in order to realize the spot size conversion of the optical element by the optical waveguide, the process steps are complicated, and there are manufacturing problems such as interface deterioration during the process and mixing of impurities.

FIG. 2 shows, as an example of the current technology, Electronics Letters Vol. 28, No. 7, 631 page (ELECTRO).
NICS LETTERS 26th March 1
992 vol. 28 No. 7 p631). This spot size converter consists of three parts I, II and III. The first portion I contains a small spot waveguide for optical coupling on the chip itself. In the second portion II, the spot size conversion is performed by the two tapered layers, and the waveguide 6 _{U in the} upper layer is used.
Has a pointed end that linearly decreases toward one end, while the width of the lower-layer waveguide 6 _L expands to the width of the output waveguide of the third portion III. is doing.

This spot size converter is a semi-insulating In
The P wafer 1a is used as a substrate, and the InP buffer layer 5 is formed thereon.
Was formed by metal organic vapor phase epitaxial growth, followed by, two layers for forming the two tapered waveguide 6 _U, 6 _L is formed by epitaxial growth. The lower layer 6 _L and the upper layer 6 _U are made of InGaAsP having different band gaps, and these layers are each formed into a taper shape by a two-step dry etching. Then these two layers 6 _U , 6 _L
An InP layer 7a is formed on the top by metal organic vapor phase epitaxial growth.

As described above, in order to manufacture this spot size exchanger, at least two epitaxial growth steps and two etching steps are required, and there is a problem that the manufacturing process becomes complicated.

[0028]

SUMMARY OF THE INVENTION A first object of the present invention is to provide an optical functional device, particularly a semiconductor light emitting device which has a wide band emission characteristic by utilizing crystal growth on a ridge and which is integrated at high density. Is to provide.

A second object of the present invention is to provide an optical device having such an optical functional device on a semiconductor substrate.

A third object of the present invention is to provide a method for manufacturing the above-mentioned optical functional device.

A fourth object of the present invention is to provide a method of manufacturing the above optical device.

A fifth object of the present invention is to provide a method of controlling (selecting) the oscillation wavelength of a semiconductor light emitting device.

[0033]

In order to achieve the above object, an invention according to claim 1 is an optical functional element, which is formed on a non-flat semiconductor substrate having a ridge shape. luminescent layer an optical functional layer, comprising an optical functional layer selected from the absorption layer and the optical waveguide layer, the light function
The layer is provided with an active layer having a multiple quantum well structure, and a composition of a portion of the active layer on the ridge is different from a composition of a portion of the active layer other than the ridge.

According to a second aspect of the present invention, in the optical functional element according to the first aspect, the ridge shape is 1 μm to 10 μm.
With a ridge width of μm, with a ridge height of 1 μm to 5 μm,
Further, it is characterized in that it has a groove width of 1 μm to 10 μm.

The invention according to claim 3 is the invention according to claim 1 or 2.
The optical functional element described above is characterized in that a diffraction grating is provided on an upper surface or a side surface of the ridge.

According to a fourth aspect of the present invention, in the optical functional element according to the second aspect, the ridge width is from 1 μm to 5 μm, and crystals of several different compositions are grown in the cavity direction. It is characterized in that it has light emission or light reception characteristics that are changed in series in the cavity direction.

According to a fifth aspect of the present invention, in the optical functional element according to the fourth aspect, a diffraction grating according to the composition is provided above the ridge, and a plurality of single lights are emitted from a single emission surface. Alternatively, it is characterized in that it receives light on the shorter wavelength side than the wavelength determined by the period of the diffraction grating.

According to a sixth aspect of the invention, in the optical functional element according to the fourth aspect, a light guide layer is provided in the ridge.

According to a seventh aspect of the present invention, in the optical functional element according to the second aspect, the ridge width is from 1 μm to 5 μm, and the ridge shape has a ridge width, a ridge height, or a groove width in a lateral direction. It is characterized in that it has a series of changes in the direction, and has different light emission or light reception characteristics depending on the location of the ridge shape that has changed in the series in the lateral direction.

According to an eighth aspect of the present invention, in the optical functional element according to the seventh aspect, a diffraction grating corresponding to a composition is provided on the upper portion of the ridge, and a single light is emitted in a parallel direction, or the diffraction grating has It is characterized in that it receives light on the shorter wavelength side than the wavelength determined by the period.

The invention according to claim 9 is the invention according to claim 1 or 2.
In the optical functional element described in the above, the optical functional layer is a semiconductor light emitting layer, and a semiconductor thin layer film having a conductivity type different from that of the non-flat semiconductor substrate is formed in a groove portion of the non-flat semiconductor substrate. To do.

According to a tenth aspect of the present invention, in the optical functional element according to the first or second aspect, the optical functional layer is a semiconductor light emitting layer, and the ridge shape of the light emitting layer of the non-flat semiconductor substrate is an inverted mesa. It is a non-flat semiconductor substrate having a structure.

The eleventh aspect of the present invention is the optical functional element according to the first or second aspect, wherein the optical functional layer is a semiconductor light emitting layer, and the non-flat semiconductor substrate is a semiconductor thin film buffer on the non-flat semiconductor substrate. It is characterized in that it is formed by forming layers.

According to a twelfth aspect of the present invention, a plurality of optical functions according to the first aspect are selected from a non-flat semiconductor substrate having a ridge shape and a light emitting element or a light receiving element arranged on the non-flat semiconductor substrate. An optical integrated device functionally combining the characteristics of the plurality of optical functional devices, wherein the optical functional device has a part of a strained multiple quantum well layer formed monolithically as an active layer. The composition of the multiple quantum well layers in the portion on the ridge is different in at least a part of the plurality of optical functional elements of the plurality of optical functional elements.

According to a thirteenth aspect of the present invention, in the optical integrated device according to the twelfth aspect, the non-flat semiconductor substrate is 1 μm.
To 10 μm, a ridge height of 1 μm to 5 μm, and a groove width of 1 μm to 10 μm.

According to a fourteenth aspect of the present invention, in the optical integrated device according to the twelfth aspect, a diffraction grating is provided on an upper surface or a side surface of the ridge of the non-flat semiconductor substrate.

According to a fifteenth aspect of the present invention, in the optical integrated device according to the fourteenth aspect, the diffraction grating has a period that varies depending on its position.

According to a sixteenth aspect of the present invention, there is provided a method of manufacturing an optical functional device having a light emitting layer, an absorption layer or an optical waveguide layer, characterized by comprising the following steps: a ridge-shaped semiconductor substrate having a ridge width Of 1 μm to 10 μm, ridge height of 1 μm to 5 μm, and groove width of 1 μm to 10 μm
A non-planar semiconductor substrate is prepared, and a strained multiple quantum well layer having a different composition on the ridge and on the part other than the ridge is formed on the non-planar semiconductor substrate by a metal organic chemical vapor deposition method.

According to a seventeenth aspect of the present invention, in the method of manufacturing an optical functional element according to the sixteenth aspect, the non-flat semiconductor substrate is formed by forming a thin semiconductor protective film layer having a composition different from that of the flat semiconductor substrate. It is characterized by being obtained by performing a non-planarization after that.

According to the eighteenth aspect of the present invention, in the method for manufacturing an optical functional element according to the sixteenth aspect or the seventeenth aspect, the ridge shape is such that a multiple quantum well structure formed on the ridge has a desired composition. The optical characteristics of the optical functional element are determined by the composition of the set multiple quantum well structure.

According to a nineteenth aspect of the present invention, in the method of manufacturing an optical functional element according to the eighteenth aspect, the optical characteristic is a band gap or a refractive index of the multiple quantum well structure, and the ridge shape is set. At least one of the ridge width, the ridge height and the groove width is changed from one end side to the other end side of the above-ridged waveguide.

According to a twentieth aspect of the present invention, in the method of manufacturing an optical functional element according to the eighteenth aspect, the optical characteristic is a light emitting or light receiving characteristic of the optical functional element, and the ridge shape is set by the ridge. It is characterized in that at least one of the width, the height of the ridge and the groove width is changed in series in the vertical direction, thereby changing the light emitting or light receiving characteristics in the cavity direction.

According to a twenty-first aspect of the invention, in the method of manufacturing an optical functional element according to the eighteenth aspect, the optical characteristic is a light emitting or light receiving characteristic of the optical functional element, and the ridge width, the ridge height, and the groove. The arrayed optical functional element is formed by setting the ridge shape so that at least one of the widths changes in series in the lateral direction, thereby changing the light emitting or light receiving characteristics in the lateral direction.

[0054]

[0055]

[0056]

[0057]

The present invention is basically produced by forming a strained multiple quantum well layer on a substrate having a ridge shape and changing the composition of the multiple quantum well layer according to the ridge shape. The present invention relates to an optical functional element such as a light emitting element and a light receiving element, and further relates to an integrated element and an optical element in which a plurality of such optical functional elements are arranged on a semiconductor substrate and the characteristics of the respective elements are functionally combined.

According to the first embodiment, according to the present invention, the width of a ridge formed in advance on a semiconductor substrate, the interval (groove width) between adjacent ridges, and the height of the ridge are set within a predetermined range. The active layer is strained by a metal organic chemical vapor deposition (hereinafter referred to as MOVPE) method to form a semiconductor multilayer film having a multiple quantum well (MQW) structure.

When a semiconductor multilayer thin film having a strained multiple quantum well structure is formed by the MOVPE method on a semiconductor substrate in which the width of the ridge, the interval between the ridges, and the height of the ridge are set in advance, a crystal plane is formed due to the characteristic of crystal growth. Causes a difference in the moving speed of the semiconductor constituent element, and causes a slight change in the composition of the strained multiple quantum well multilayer film on the ridge. Therefore, an optical functional element having a slightly different thickness and composition of the active layer can be formed on the plurality of ridges, and its emission wavelength characteristic can be controlled in a wide range.

In controlling the emission wavelength characteristic , the main factor when the groove width is changed is due to the change in the composition of the quantum well layer. FIG. 3 shows In _1-x Ga _x As /
2 shows the result of theoretical calculation of the relationship between the composition x of Ga and the light emission characteristics in an InGaAsP (λg = 1.1 μm) system using the thickness of the quantum well layer as a parameter. Since the change in the film thickness of the quantum well layer on the ridge by the MOVPE method is 10% or less for any change in the groove width from 1 μm to 10 μm,
The change in the emission wavelength is mainly due to the change in the composition of the quantum well structure.

For example, in FIG. 3, when the thickness of the quantum well layer is 30Å, when the Ga composition is reduced from 0.57 to 0.35 by about 40%, the emission wavelength is 1. It changes from 3 μm to 1.55 μm. This decrease in composition is due to the difference in the moving speed of In and Ga on the crystal plane,
Alternatively, it is an appropriate amount of change in consideration of the ratio of the crystal growth surface on the ridge of the surface that makes the difference visible.

On the other hand, in the mask selective growth method mentioned in the prior art, the change in the emission wavelength is due to the change in the thickness of the quantum well layer rather than the change in the composition, as indicated by the arrow B in FIG. is there.

In the above case, an element which emits light in a wide wavelength range from the same emission surface can be obtained by growing several kinds of different crystals in the cavity direction. In this case, the width of the groove formed on the semiconductor substrate is 1 μm or more, preferably 1 to 10 μm, while the width of the ridge formed between two such two grooves is 1 μm or more, preferably 1 μm.
.About.5 .mu.m, height 1-5 .mu.m, preferably 1-3 .mu.m. It is preferable to provide a light guide layer in the ridge.

In this growth method, the composition can be controlled by the size of the groove and the size of the ridge, and as a result, the emission wavelength can be significantly controlled to about 300 nm or more.

FIG. 4A shows an example of the structure of a semiconductor light emitting device manufactured by such a manufacturing method. The semiconductor light emitting device includes a light emitting diode (LED) and a laser diode (LD). In FIG. 4A, reference numeral 1 is n
-InP substrate, 6 is a light emitting layer (for example, InGaAsP / I
Strained MQW layer made of nGaAs), 6a is groove MQW
A layer, 7 is a p-InP clad layer, 8 is an n-InP buried layer, 9 is a p-InP layer, and 10 is a contact layer.

However, in order to further improve the characteristics of the semiconductor light emitting device by such a manufacturing method, it is necessary to solve two problems.

Specifically, for example, the ridge width is 1.5 μm,
When crystal growth is performed on a non-flat semiconductor substrate 1 having a groove width of 2 μm and a groove height of 2 μm so that the emission wavelength characteristic of the flat portion is in the 1.35 μm band, the composition of the light emitting portion 6 on the ridge is The width is 1.55 μm band, and the composition of the groove MQW layer 6a is 1.3 μm band. Although the composition of the light emitting portion 6 on the ridge does not change much in the vicinity of the 1.55 μm band with respect to the compositions of the emission wavelength characteristics of the flat portion having the same shape in the 1.45 μm band and the 1.55 μm band, the groove MQW layer 6a The composition of 1.4
It becomes a μm band and a 1.5 μm band.

Thus, the composition of the light emitting portion on the ridge is 1.5.
While it is constant in the 5 μm band, the composition of the groove portion is supposed to change.

When the light emission characteristics of such a semiconductor light emitting element are analyzed by computer simulation, the following results are obtained. That is, the closer the composition of the groove MQW layer 6a is to the composition of the light emitting portion, the smaller the potential difference in the vertical direction between the two parts becomes, so that the leakage of current to the groove becomes large and the threshold current value increases.

FIG. 4B shows a case where the ridge width is 1.5 μm, the groove width is 2 μm, and the groove depth is 2 μm, and the composition of the multiple quantum well layer in the groove portion is 1.3 μm, 1.4 μm, and 1.5 μm. 4A and 4B are examples of simulation results by a simple model in which the groove MQ in the structure of FIG.
It shows the emission characteristics of the optical output with respect to the injection current when the composition of the W layer is changed. In FIG. 4B, the solid line shows an ideal case where the crystal has no defects, the broken line shows the case where the crystallinity is insufficient, and the case where there are 10 ¹² defects per cm ³ .

As shown in FIG. 4B, the first problem is that the threshold value of the injection current of the light emitting element changes significantly depending on the composition of the MQW layer in the groove. The second problem is considered to be that the light emission characteristics change due to crystallinity, and the light emission characteristics according to the current technology are close to the dotted line. In order to improve such emission characteristics, it is necessary to make the injection current threshold uniform and improve the crystallinity.

Although the crystallinity depends on the conditions at the time of crystal growth, it largely depends on the damage caused at the time of producing the pattern of the underlying non-flat semiconductor substrate. When the crystal of the light emitting portion is directly grown on the non-planar semiconductor substrate manufactured by the dry process, the crystallinity is lowered, and the current light emitting characteristics are obtained. In order to further improve the characteristics of the current device, it is necessary to reduce the damage of the non-flat semiconductor substrate including the treatment before growth.

In the semiconductor light emitting device of the present invention, it is preferable that a semiconductor thin film having a conductivity type different from that of the substrate is formed in the groove.

The ridge shape of the light emitting layer is preferably a non-flat semiconductor substrate having an inverted mesa structure.

Further, it is preferable that the semiconductor thin film buffer layer is formed on the non-flat semiconductor substrate.

The method for manufacturing the semiconductor light emitting device is as follows.
A non-flat semiconductor substrate is formed after a semiconductor protective thin film layer having a composition different from that of the substrate is formed on the flat semiconductor substrate.

Specifically, in a semiconductor light emitting device having a strained multiple quantum well (MQW) structure on a predetermined non-planar semiconductor substrate by a metal organic chemical vapor deposition (MOVPE) method, introduction of a semiconductor current block thin film layer, semiconductor buffer This is to form a thin film layer and introduce an inverted mesa ridge structure.

By introducing a semiconductor current blocking thin film layer, forming a semiconductor buffer thin film layer, and forming a strained multiple quantum well thin film on a non-flat semiconductor substrate by introducing an inverted mesa ridge structure, a semiconductor having high crystallinity and high injection efficiency can be obtained. It becomes possible to manufacture a light emitting device, and it is possible to control the emission wavelength characteristic by controlling the composition by the pattern shape and also the amount of wavelength shift, so that a more advanced semiconductor light emitting device can be realized.

The optical integrated circuit according to the second embodiment of the present invention comprises a semiconductor light emitting device (LD) and a semiconductor photodetecting device (P
D), a semiconductor photodetecting element for detecting light having a wavelength longer than the detection wavelength, and a wavelength filter arranged between the photodetecting elements, which are integrated by coupling them through an optical waveguide. It can be made to work as a transmitting element of, and a light detecting element of two wavelengths.

In the optical integrated circuit of the present invention, the semiconductor multilayer film is preferably formed on the ridge formed between the two grooves.
As a result, the effective band gap of the multilayer film changes depending on the ridge width, groove width, and groove depth. By utilizing this, a light emitting layer, an absorbing layer, or an optical waveguide layer is formed on the same substrate.

First, the formation of a ridge preferably used in the present invention, and the crystal growth thereon and the band gap change of the grown multilayer film will be described.

As shown in FIG. 5A, after forming an oxide film or a nitride film 2 on a flat substrate 1 by dry etching with a reactive gas ion such as chlorine, or by wet etching using a hydrochloric acid system. A ridge (or mesa) 3 having grooves 4 on both sides as shown in FIG. 5C is formed. The mesa direction is the same as in the fabrication of a normal semiconductor laser, and is the <011> direction (so-called reverse mesa direction) on a (100) substrate. As another method of forming the ridge, there is a method of utilizing selective growth. In this case, in the first mask pattern, unlike the case of etching, the portion which becomes the groove 4 becomes the insulating film 2a as shown in FIG. 5B. Also by this selective growth method, a ridge as shown in FIG. 5C is formed. In FIG. 5C, the ridge width dw and the groove width dg are determined by the distance between the tops of the mesas, and the height h of the mesas is the difference between the flat surfaces of the tops of the mesas and the bottoms of the grooves. A semiconductor multilayer film (multiple quantum well structure) is grown on the non-flat substrate having the ridge formed in this way by the MOVPE method.

In the multiple quantum well structure grown by the above method, the composition of the quantum well structure changes depending on the ridge width, the groove width, and the ridge height, and the band gap wavelength changes. In FIG. 6A, the height is 2 μm, and 1, 2, 3, 4,
The groove width is 1 to 1 for the ridge having 5 kinds of width of 5 μm.
It is a graph showing the bandgap wavelength of the multiple quantum well structure on the ridge when changed to 0 μm by the shift amount from that of the multiple quantum well structure simultaneously grown on the flat region. FIG. 6B shows the results of the shift when the ridge width is fixed and the groove width is changed in series for three types of heights of 1, 2, 1.6 and 2.0 μm. As shown in FIGS. 6A and 6B, a wavelength shift up to 300 nm can be realized by growing a multiple quantum well structure on a non-flat substrate. The bandgap wavelength shifts to the longer wavelength side as the ridge width becomes narrower and the groove width becomes narrower.

As the multiple quantum well structure, InGaAs is used.
/ InGaAsP, InAsP / InGaAsP, In
GaAsP / InGaAsP, InGaAs / InP,
InGaAs / InAlAs, InGaAs / InGa
Any system such as AlAs may be used.

In the spot size exchange type optical element according to the third embodiment of the present invention, the composition and thickness of the epitaxial film to be grown thereon can be changed depending on the shape of the ridge structure formed on the substrate. Is used. When the composition and thickness of the epitaxial film change, the bandgap wavelength and the refractive index change.

In the present invention, it is understood that the ridge-shaped waveguide is composed of a groove and a ridge, and has the groove and the ridge. Therefore, the size of the ridge-shaped waveguide in the present invention includes not only the width and height of the ridge but also the width of the groove.

As the epitaxial layer, 17 Å InG is used.
aAs layer and InGaAsP layer 15 having a wavelength of 1.1 μm
7 and 8 show changes in PL (photoluminescence) wavelength in the case of growing a quantum well structure consisting of 0Å. FIG. 7 shows the dependence of the wavelength shift amount on the groove width dg when the ridge height h is 2.0 μm, using the ridge width dw as a parameter. Also, FIG.
Shows the same dependence by fixing the groove width dg to 2.0 μm and using the ridge height h as a parameter. The PL emission wavelength on a flat substrate without a ridge structure is about 1.27.
μm. In FIGS. 7 and 8, if the ridge structure size is changed in the light guiding direction, the epitaxial layer grown using this as a substrate changes the bandgap wavelength along the light guiding direction. It shows that the refractive index also changes. Therefore, by forming a waveguide having this layer as a core, it is possible to change the refractive index distributions of the core and the clad at both end faces of the waveguide, and as a result, an optical element having a waveguide with different spot sizes is formed. Easy to implement.

[0088]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings.

Example 1 Light Emitting Element In this example, crystal growth was carried out by MOVPE method on an InP substrate having a non-flat surface with varying ridge width, ridge spacing (groove width) and ridge height. And a light emitting element (light emitting diode, LED, and laser diode, which emits light in the vicinity of 1.3 μm to 1.65 μm as an emission wavelength region,
LD).

9A to 9F show manufacturing steps of the light emitting device of this example.

First, as shown in FIG. 9A, a mask pattern having a predetermined ridge size is formed of an oxide film or a nitride film 2 on the InP substrate 1.

Next, as shown in FIG. 9B, dry etching by a reactive gas ion such as a halogen system such as chlorine and bromine or monovalent hydrogen such as methane and ethane, or an inert gas ion such as Ar. The groove 4 for forming the ridge 3 is formed by milling or wet etching using chlorine, sulfuric acid, bromine or the like. The formation direction of the ridge 3 is the <011> direction (so-called reverse mesa direction) on the InP (100) substrate. As will be described later, empirically, this direction also has the largest shift amount.

As a method of forming the ridge 3, there is also a method of utilizing selective growth. In this case, the mask pattern has an inversion relationship with that in the case of etching, and becomes a groove as shown in FIG. 9B. The part becomes an insulating film. This way too
The ridge 3 as shown in FIG. 9C is formed. A semiconductor substrate having a film thickness of about 10 is previously formed by the MOVPE method described later.
After crystal growth of an optical waveguide layer made of InGaAsP of 00Å, a ridge-shaped non-flat substrate as shown in FIG. 9C may be formed. In this case, the degree of freedom in designing the optical functional element increases. In FIG. 9C, the ridge width dw and the groove width dg are measured at the distance over the ridge in consideration of the case where the ridge shape is not vertical, and the height h of the ridge 3 is measured on the flat surface between the ridge upper portion and the groove bottom. It was the difference.

Subsequently, as shown in FIG. 9D, MOVP is formed on the InP substrate 1 on which the ridge 3 is formed and whose surface is not flat.
The semiconductor multilayer films 5, 6, 7 having a laser structure are grown by the E method.

The semiconductor multilayer films 5, 6 and 7 are grown in a reduced pressure vertical MOVPE growth furnace at a pressure of 70 Torr and a growth temperature of 630.degree. Raw materials are TMI (trimethylindium), TEG (triethylgallium), AsH
₃ (arsine) and PH ₃ (phosphine) were used.

The semiconductor multi-layer film is composed of the n-InP buffer layer 5 and 4 to 6 cycles of 17 Å InGaAs / 150 Å I.
It is composed of an nGaAsP (λg = 1.1 μm) strained MQW light emitting layer, an InGaAsP optical waveguide layer 6, and a p-InP cladding layer 7.

Further, by masking the upper portion of the ridge, FIG.
As shown in (E), after growing the n-InP burying layer 8, the mask is removed and the p-InP burying portion 9 is formed on the entire surface.
And the p-InGaAsP contact part 10 was grown. By controlling the growth conditions such as the growth temperature and the doping amount, or by controlling the ridge width dw, the growth in FIGS. 9D and 9E can be consistently performed.

Finally, as shown in FIG. 9F, the p-type electrode 11 is formed on the p-InGaAsP contact portion 10 which is the uppermost multilayer film on the ridge, and the n-type electrode 12 is formed on the InP substrate 1.
Is formed and alloyed, and then cleaved or electrodes are separated to form a device. By the current injection, laser light emission is obtained in the arrow direction.

Through the above manufacturing steps, an embedded light emitting device can be realized on the InP substrate. When a current is injected into the light emitting element, laser emission is observed from the end face of the ridge 3.

In order to compare the difference between the light emitting characteristic of the light emitting element on the ridge shape according to the present invention and the light emitting characteristic of the light emitting element on the flat substrate according to the prior art, FIGS.
The characteristics of the present invention are shown in (C).

FIGS. 10 (A) to 10 (C) show In _1-x Ga _x As / InGaAsP (λg =) having a well layer thickness of 17 Å formed on a ridge-shaped substrate and containing 0.5% tensile strain.
It shows the shift amount of the emission wavelength of the quantum well layer made of 1.1 μm). After the strained quantum well layer was crystal-grown on a flat substrate as in the present invention, a predetermined active layer width was formed by dry etching, and the light emitting element filled with the semiconductor thin film layer again had an emission wavelength of 1. It is 27 μm.

In FIG. 10A, the height h of the ridge is 2 μm.
The relationship between the ridge width dw and the amount of change in the emission wavelength when the ridge width dw is changed from 1 μm to 6 μm is shown with the groove width dg as a parameter. Figure 1
As can be seen from 0 (A), the shift amount of the emission wavelength significantly increases with respect to the ridge width dw when the groove width dg is 3 μm or less. When the ridge width dw is 4 μm or more, the shift amount of the emission wavelength is extremely small.

In FIG. 10B, the height h of the ridge is 2 μm.
The relationship between the groove width dg and the amount of change in the emission wavelength when the groove width dg is changed from 1 μm to 10 μm is shown as a characteristic with the ridge width dw as a parameter. As can be seen from the figure, when the ridge width dw is 2 μm or less, the shift amount of the emission wavelength changes significantly with respect to the change of the groove width dg, and particularly when the groove width dg is 6 μm or less.

In FIG. 10C, the height h of the ridge is from 1.2 μm to 2.2 μ with the groove width dg being constant at 1.5 μm.
It shows the characteristics with the ridge width dw as a parameter with respect to the relationship with the amount of change in the emission wavelength when changed to m. It can be seen that the shift amount of the emission wavelength is remarkable with respect to the height h of the ridge. That is, FIG. 10 (A)-
From the characteristics of (C), it is found that the variation of the emission wavelength is extremely large when the ridge width dw, the height h, and the groove width dg are 10 μm or less, and the emission wavelength can be controlled by a processing technique such as a ridge. Shows. In addition, the light emission characteristics have a narrower ridge width dw and a narrower groove width dg.
Shift to the longer wavelength side. The emission wavelength according to the prior art utilizing the growth on a flat plate is 1.27 μm, and the present invention can realize a maximum emission wavelength of 1.6 μm with a maximum shift amount of 300 nm.

In order to determine the main cause of the change in the shift amount of the emission wavelength according to the present invention, InGaAs is formed on the ridge substrate.
(Λg = 1.1 μm) When a quantum well layer is grown,
FIG. 11A to FIG. 11C show results obtained for the relationship between the ridge width dw, the groove width dg, the ridge height h, and the quantum well layer thickness.
It shows in (C). The results of FIGS. 11A to 11C are shown so as to correspond to the respective dimensions of the example. Figure 1
1 (A) is the dependence of the thickness of the quantum well layer on the ridge width. The phenomenon in which the film thickness sharply increases when the ridge width dw is 1.5 μm or less reflects the movement of In particularly on the crystal growth surface. It is a thing.

FIG. 11B shows the characteristics of the groove width dg and the thickness of the quantum well layer. Further, FIG. 11C shows the height h of the ridge.
And the characteristics of the quantum well layer thickness. It can be seen that in both cases, the fluctuation of the film thickness of the quantum well layer is small. FIG. 11 (A)-
From the characteristics of (C), in the range of the present invention in which the ridge width dw, the height h, and the groove width dg are 10 μm or less, the thickness of the quantum well layer slightly increases, but the change amount of the emission wavelength largely changes. It can be judged that the cause is a change in the composition of the quantum well layer due to the shape effect.

In the above example, the strained MQW layer is formed of InGaAs /
InGaAsP is an embodiment, but other than this, for example, InGaAsP / InGaAsP, InGaAs / In
P, InAsP / InGaAsP, InGaAs / In
AlAs, InGaAs / InGaAlAs, InP
It is also applicable to the III-V MQW material system that can be grown on the substrate. In addition, GaAs is used as the substrate,
MQ of / AlGaAs, InGaAs / AlGaAs, etc.
By growing the W structure, it is possible to realize the above-described effect of controlling the emission characteristics in a short-wave system (from 0.8 μm to 1.1 μm).

(Example 2) DFB type laser This example relates to a method of manufacturing a DFB laser for improving the controllability of the oscillation wavelength of the light emitting device described in Example 1 and for oscillating in a single spectrum. .

FIGS. 12A to 12C show D according to this embodiment.
It shows the formation of a diffraction grating on a ridge-shaped substrate for an FB laser.

In FIG. 12A, a diffraction grating 13 having a predetermined period is formed in a region where a ridge is to be formed on a flat substrate by using an electron beam lithography technique or a laser interference exposure technique, and then the substrate is formed. The ridge 3 is manufactured. Subsequent processes for forming a semiconductor multiple quantum well and for manufacturing a light emitting device are the same as those in the first embodiment.

In FIG. 12B, after the semiconductor optical waveguide layer 14 is formed on the substrate by the MOVPE method, the diffraction grating 13 having a predetermined period is formed in the region where the ridge is formed by using the electron beam lithography technique or the like. After that, the ridge 3 is formed on the substrate. The subsequent processes for forming the semiconductor multiple quantum well and the light emitting device can be realized in Example 1, but the formation of the optical waveguide layer becomes unnecessary.

FIG. 12C shows an example in which the diffraction grating 15 is formed on the side surface of the ridge 3. A diffraction grating having a predetermined period is formed on a mask for forming a ridge using an electron beam lithography technique or the like, and the diffraction grating 15 is formed on the side surface of the ridge 3 along with the fabrication thereof. Subsequent processes for forming a semiconductor multiple quantum well and for manufacturing a light emitting device are the same as those in the first embodiment.

In this embodiment, a single spectrum is obtained when a laser is operated by injecting a current to emit light.

(Third Embodiment) Groove Width Modulation Laser Array In this embodiment, the groove 4 is formed with the ridge width dw and the height h kept constant.
Of the semiconductor laser array in which the groove width dg of 4 is changed in four ways. 13A to 13E show a procedure for manufacturing the semiconductor laser array according to this embodiment.

First, as shown in FIG. 13A, n-type I
A stripe pattern made of an oxide film or a nitride film 2 is formed on the nP (100) substrate 1 by photolithography. Next, as shown in FIG. 13B, the ridge 3 and the groove 4 are dry-etched using chlorine gas.
Forming a groove width modulation type non-flat substrate. Here, the ridge 3 having a ridge width dw of 1.5 μm is <011>.
Direction (so-called reverse mesa direction), the height h of the ridge is 2 μm, and the groove width dg is 1.5 μm sequentially from the right.
It changes to 0 μm, 3.5 μm, and 4.0 μm.

Subsequently, as shown in FIG. 13C, n-type In
InP buffer layer 5 on P substrate 1, InGaAsP waveguide layer and 5 cycles of 20 Å InGaP well / 150 Å I
A light emitting layer having a strained quantum well structure formed of an nGaAsP barrier, an optical waveguide layer 6 and a p-InP clad layer 7 are formed. The growth of these semiconductor multilayer films 5, 6 and 7 is performed by using trimethylindium, trimethylgallium, arsine,
Using phosphine as a raw material gas for semiconductors and hydrogen selenide and diethyl zinc as a doping gas, 63
It was carried out by metalorganic vapor phase epitaxy at 0 ° C. and 0.1 atm.

Further, as shown in FIG. 13 (D), n-In is used for current blocking by metalorganic vapor phase epitaxy.
After growing the P layer 8 and the p-InP layer 9, p-InG
The aAsP contact layer 10 is formed. The crystal growth of FIGS. 13C and 13D can be performed once depending on the conditions, but when the thickness of the burying layer, the doping control, and the like are properly controlled, the growth is performed in two or three times.

Subsequently, as shown in FIG. 13E, a p-electrode 11 and an n-electrode 12 are formed on the upper and lower sides, and a separation groove 16 is provided to electrically separate them in the lateral direction. The element thus manufactured is mounted on the heat sink 17, the lead wire 18 is bonded, and then the currents I ₁ , I ₂ , I ₃ , and I ₄ are injected from the lead wire 18. From the laser emission A in the direction indicated by the arrow in FIG.
₁ , A ₂ , A ₃ , and A ₄ are observed.

The oscillation wavelength is in good agreement with the result of the photoluminescence measurement, and light emission with good directivity corresponding to the composition change is obtained. The emission spectrum on the flat substrate observed by the photoluminescence method has a peak at 1.3 μm, while the adjacent groove width dg is 1.5 μm.
The peaks of laser emission A ₁ , A ₂ , A ₃ , and A ₄ from the ridge end face of m, 3.0 μm, 3.5 μm, and 4.0 μm are 1.55 μm, respectively, as shown in FIG.
m, 1.5 μm, 1.45 μm, 1.4 μm.

(Embodiment 4) Groove width modulation type laser array with a diffraction grating In this embodiment, a diffraction grating is introduced in Embodiment 3 in order to improve controllability of an oscillation wavelength and to oscillate with a single spectrum. It is a thing. FIGS. 15A to 15F show the procedure for producing the groove width modulation type laser array according to the present embodiment.

First, as shown in FIG. 15B, InP
The diffraction grating 13 is formed on the substrate 1 by using the electron beam lithography technique. The diffraction grating 13 has a width of 5 μm and the periods from the right are 2400Å, 2300Å, 2200Å,
It changes to 2100Å. An optical waveguide layer, for example, an InGaAsP layer may be previously formed by crystal growth before the diffraction grating 13 is formed on the InP substrate 1. In that case, the growth process of the corresponding waveguide layer in the subsequent crystal growth may be performed. Is omitted.

Next, as shown in FIG. 15A, a stripe pattern made of an oxide film or a nitride film 2 is formed in the same manner as in Example 3, and then dry etching is performed as shown in FIG. 15B. A non-flat substrate having the ridge 3 and the groove 4 is manufactured, and further, the semiconductor multilayer films 5, 6 and 7 and the buried layers 8 and 9 are formed on the non-flat substrate according to FIGS.
Grow 10 crystals. Next, as shown in FIG. 15E, electrodes 11 and 12 are formed on the buried layer 10 and the semiconductor back surface, respectively, mounted on a heat sink 17, and a lead wire is attached to the electrode 11. When currents I ₁ , I ₂ , I ₃ , and I ₄ are injected from the lead wire 18, laser emission A ₁ , A ₂ , A ₃ , and A ₄ from the end face of each ridge 3 in the direction shown by the arrow in FIG. Is observed. Laser emission A
_{For 1} , A ₂ , A ₃ , and A ₄ , four-wave single mode oscillation as shown in FIG. 16 is obtained.

(Embodiment 5) Ridge Width Modulation Laser Array This embodiment relates to a semiconductor laser array in which the height h of the ridge 3 and the groove width dg are kept constant and the width dw of the ridge 3 is changed in four ways. is there. A procedure for manufacturing the ridge width modulation type laser array according to the present embodiment is shown in FIGS.

First, as shown in FIG. 17A, n-type I
A stripe pattern made of an oxide film or a nitride film 2 is formed on the nP (100) substrate 1 by photolithography.

Next, as shown in FIG. 17B, a groove width modulation type non-flat substrate having the ridge 3 and the groove 4 is formed by dry etching using chlorine gas. Here, the height h of the ridge is fixed to 2 μm and the groove width dg is fixed to 1.5 μm, and the ridge (mesa) width dw is 1.5 μm from the right.
It changed to 0 μm, 2.5 μm, and 3.0 μm.

Subsequently, as shown in FIG. 17C, as in Example 3, 5 cycles of 20 Å InGaP well / 150 was used.
A crystal having a light emitting layer 6 having a strained quantum well structure composed of a Å InGaAsP barrier is formed.

Further, by performing the buried growth and the electrode formation according to FIGS. 17D and 17E, it is possible to obtain the oscillation characteristic similar to that of FIG. That is, the emission spectrum on the flat substrate observed by the photoluminescence method is 1.3 μm.
m has a peak, while the ridge width is 1.5 μm,
The emission peaks from the ridge are 1.55 μm, 1.
It changes to 5 μm, 1.45 μm, and 1.4 μm.

Example 6 Light-Receiving Element In this example, a light-receiving layer is formed in place of the light-emitting layer in Example 1, and the manufacturing process is the same as in Example 1. Like the light emitting element, the light receiving element of this embodiment responds to light according to the composition of the light receiving layer formed on the ridge. Therefore, when light is incident in the direction opposite to the arrow in FIG. 9F, the photoresponse is detected by the generation of current in the electrode 11. For example, an element having a composition of 1.3 μm does not respond even if 1.55 μm light is incident from the end face, but an element that responds to only 1.3 μm light when 1.3 μm and 1.55 μm light are simultaneously injected. Becomes

(Embodiment 7) According to the method shown in FIGS. 9A to 9F of the optical integrated device embodiment 1,
In addition, various optical elements can be realized. For example, it is an optical waveguide having various optical characteristics depending on the composition, an optical modulator or an optical switch that operates in a specific wavelength region, a broadband semiconductor amplifier, or the like. An optical integrated device with high interelement coupling efficiency can be realized by simultaneously manufacturing these on one substrate.

Specifically, there is a monolithic optical integrated circuit for reception in the coherent communication system. In this integrated circuit, as shown in FIG. 18, a wavelength tunable multi-electrode DFB laser 30 as a local oscillation light source and a directional coupler type 3 dB were used.
It is composed of a coupler 31, a waveguide type PIN photodetector 32, a butt joint section 33, and an optical waveguide for optical signal propagation. A device with basic operation has already been realized by combining crystal growth 4 to 5 times and advanced process technology (Takeuchi et al., IEICE Transactions C-
1, Vol. J73-J-1, No. 5, pp360-
367 May 1990).

However, since the process is repeated many times, the characteristics such as optical coupling efficiency are insufficient, and the yield of the device is extremely low. By using the present invention, the optical integrated circuit can be realized by a single growth by first forming a mask pattern on the substrate,
Excellent properties such as coupling efficiency can be obtained. This results in a significant reduction in manufacturing cost due to crystal growth and simplification of the process.

As described above in detail with reference to Examples 1 to 7, according to the present invention, a plurality of optical functional elements having slightly different optical characteristics on the semiconductor substrate and an optical function integrated at high density are provided. Since the device can be realized relatively easily, the breakthrough of the optical communication system can be realized.

(Embodiment 8) Groove width modulation type super luminescent photodiode (SLD) A groove width modulation type super luminescent photodiode (SLD) according to this embodiment is shown in FIGS. 19 (A) to 19 (E). In this embodiment, the width of the ridge and the depth of the groove are made constant, and the groove interval is changed in five ways.

First, as shown in FIG. 19A, n-type I
A pattern made of an oxide film or a nitride film 2 is formed on the nP (100) substrate 1 by photolithography. This pattern is a plate-like mask having a stripe portion to be a ridge and a step in a portion sandwiching the stripe portion. n type I
Before the pattern is formed on the nP substrate 1, an optical waveguide layer such as In
When the GaAsP layer is crystal-grown, the corresponding growth process of the waveguide layer in the subsequent crystal growth is omitted.

Next, as shown in FIG. 19B, a groove width modulation type non-flat substrate having grooves 4 and ridges 3 is formed by dry etching using chlorine gas. Here, the ridge 3 is formed in the <011> direction (so-called reverse mesa direction), the ridge width dw is 1.5 μm, and the ridge height h is 2 μm. The groove width dg is 1.
5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 10.
It is 0 μm.

Subsequently, as shown in FIG. 19C, the InP buffer layer 5, the InGaAsP waveguide layer, and 5 cycles of 20Å In are formed on the substrate 1 having the ridge 3 and the groove 4.
A light emitting layer 6 having a strained quantum well structure composed of a GaP well / 150 Å InGaAsP barrier and a p-InP clad layer 7 are formed. These growth is performed by metalorganic vapor phase epitaxy at 630 ° C. and 0.1 atm using trimethylindium, trimethylgallium, arsine, and phosphine as source gases for semiconductors and hydrogen selenide and diethylzinc as doping gases. .

The emission spectrum on the flat substrate observed by the photoluminescence method has a peak at 1.3 μm, while the adjacent groove widths are 1.5 μm and 3.0 μm.
m, 3.5 μm, 4.0 μm and 10.0 μm, the peaks of light emission from the ridge are 1.55 μm.
m, 1.5 μm, 1.45 μm, 1.4 μm, 1.35
It becomes μm.

Further, according to FIG. 19D, after p-InP cladding layer 7'is added by the metalorganic vapor phase epitaxy method, n-InP layer 8 and p are stacked for current blocking.
After growing the -InP layer 9, the p-InGaAsP contact layer 10 is formed. The crystal growth in FIGS. 19C and 19D can be performed once depending on the conditions, but when the thickness of the buried layer, the toping control, and the like are accurately performed, the crystal growth is performed in two or three times.

After that, as shown in FIG. 19E, a p-electrode 11 and an n-electrode 12 are formed on the upper and lower sides, and a separation groove 16a is provided to separate the respective portions on the ridge where the composition changes.

The element thus manufactured is mounted on the heat sink 17, and the wire 18 is attached to the electrode 1.
After bonding to No. 1, current injection of I ₁ to I ₅ was performed to each electrode, and in the direction indicated by arrow A in FIG. 19 (E), thin solid lines A ₁ to A in FIG. _Five
Light emission with good directivity corresponding to the composition that is in agreement with the photoluminescence measurement result as shown in is observed.

By supplying a current to all the electrodes at the same time, 1.3 to 1.6 μm as shown by the thick solid line A in FIG.
An element that emits light in a wide range can be obtained. At that time,
Light emission is observed in the direction indicated by arrow B in the direction opposite to arrow A in FIG. This is because light with a short wavelength emitted from the front surface is absorbed in the area on the opposite side.

(Ninth Embodiment) Ridge Width Modulation SLD A ridge width modulation SLD according to the present embodiment is shown in FIGS.
It shows in (E). In this embodiment, the width and depth of the groove are constant,
The ridge width is changed in five ways.

First, as shown in FIG. 21A, n-type I
A pattern made of an oxide film or a nitride film 2 is formed on the nP (100) substrate 1 by photolithography. This pattern is a plate-shaped mask having a polygonal stripe portion which becomes a ridge and a step in a portion sandwiching the polygonal stripe portion.

Next, as in the eighth embodiment, FIG.
The ridge 3 and the groove 4 as shown in (B) are formed. Here, the ridge 3 is formed in the <011> direction (so-called reverse mesa direction), and has five types of ridge widths dw of 1 μm, 2 μm, 3 μm, 4 μm, and 10 μm in which the ridge width changes stepwise every 300 μm. The ridge height h and the width dg are 2 μm and 2.5 μm, respectively.

Subsequently, in the same manner as in Example 8, FIG.
As shown in (C), the InP buffer layer 5, InGaA
Waveguide layer of sP and 5 cycles of 20Å InGaP well / 1
A light emitting layer 6 having a strained quantum well structure made of a 50 Å InGaAsP barrier and a p-InP clad layer 7 are formed.

Ridge width 1 μm, 2 μm, 3 μm, 4 μ
The peak wavelengths of the emission spectra obtained by photoluminescence measurement of the crystals formed on the ridges of m and 10 μm are 1.55 μm, 1.5 μm and 1.45 μ, respectively.
m, 1.4 μm, 1.35 μm.

Then, in order to obtain an embedded structure, as shown in FIG.
After forming a mask of an oxide film or a nitride film 2'as shown in FIG. 1 (D), dry etching is performed as shown in FIG. 21 (E). Buried growth and electrode formation are the same as in the case of Example 8, and the shapes are the same as in FIGS. 19D and 19E. The emission characteristics are also as shown in FIG.

(Embodiment 10) Ridge height modulation type SLD FIG. 22A shows a ridge height modulation type SLD according to this embodiment.
~ (E). In this embodiment, the ridge width and the groove width are made constant, and the ridge height (groove depth) is changed in five ways.

First, as shown in FIG. 22A, the n-type I
A pattern made of an oxide film or a nitride film 2 is formed on the nP (100) substrate 1 by photolithography. This pattern is a plateau-like mask having a step in a part that sandwiches the part that becomes the ridge.

Next, n-InP is selectively grown between the masks by a metal organic chemical vapor deposition method or a metal organic molecular beam epitaxy method. At this time, the growth rate changes according to the width of the mask, so that a step is formed in the height h of the ridge as shown in FIG.

Here, the ridge 3 is formed in the <011> direction (so-called reverse mesa direction), and the ridge height changes stepwise at 300 nm intervals of 1.2 μm and 1.4 μm.
It has five types of ridge heights h of 1.6 μm, 1.8 μm, and 2.0 μm, and the ridge width dw is 1.5 μm.

Then, in order to make the groove width constant, FIG.
A mask made of the oxide film or the nitride film 2 as shown in (C) is formed, and as shown in FIG. 22D, a non-flat substrate view in which only the height of the ridge changes by dry etching is obtained.
Here, the groove width is 2.5 μm.

Thereafter, in the same manner as in Example 8, the InP buffer layer 5, the InGaAsP waveguide layer, and 20 periods of 5 periods were used.
Light emitting layer 6 having a strained quantum well structure composed of Å InGaP well / 150 Å InGaAsP barrier, and p-InP
The clad layer 7 is formed.

Ridge height 1.2 μm, 1.4 μm, 1.
The peak wavelengths of the emission spectra obtained by photoluminescence measurement of the crystals formed on the ridges 3 of 6 μm, 1.8 μm, and 2.0 μm are 1.35 μm,
1.4 μm, 1.45 μm, 1.5 μm, 1.55 μm
become.

Further, the buried growth and the electrode formation are the same as in the case of the eighth embodiment, and the shapes are the same as those in FIGS. 19D and 19E. The emission characteristics are also as shown in FIG.

23A to 23C show a modification in which the height of the ridge is modulated.

As shown in FIG. 23A, FIG.
As shown in FIG. 23B, a non-flat substrate in which the width and height of the ridge change is formed as a result of selective growth. A mask made of an oxide film or a nitride film 2'as shown in FIG. 23C is formed to make the ridge width constant, and a non-flat substrate in which only the height of the ridge is changed is obtained by dry etching. The shape is shown in Figure 2.
The same non-planar substrate as 2 (D) is obtained. The same applies hereinafter.

As described above in detail with reference to Examples 8 to 10, a superluminescent photodiode having a high density integration is realized by the present invention, and measurement or evaluation utilizing the high wavelength band characteristic is realized. A dramatic development of the law is expected.

(Embodiment 11) Example of semiconductor light emitting device of current blocking layer introduction type A semiconductor light emitting device in which a current blocking layer is introduced into a groove portion of a non-planar semiconductor substrate is shown in FIGS. 24 (A) to 24 (E). Shown in.

First, the oxide films 2 and 2 are formed on the n-InP substrate 1.
After forming b (the same may be used), a predetermined etching oxide film pattern for forming a non-flat semiconductor substrate is formed (see FIG. 24A).

Next, dry etching is performed by reactive ion etching (RIE) using chlorine gas, for example.
A groove 4 is formed in the n-InP substrate 1.

After that, the oxide film 2 other than the upper portion of the ridge portion 3 is removed to form a non-flat semiconductor substrate (see FIG. 24B).

By metal organic vapor phase epitaxy (MOVPE) method, pressure 70 Torr, substrate temperature 600-700 ° C.,
Trimethylindium (TMI) and phosphine (PH
₃ ) is a p-type dopant diethylzing (Zn (C ₂ H
₅ ) ₂ ) is supplied to form the p-InP layer 19 at 0.2 to 0.
It grows up to about 3 μm (see FIG. 24 (C)).

The thin film growth layer having a conductivity type different from that of the non-flat semiconductor substrate is hereinafter referred to as "current blocking layer".

Next, after removing the oxide film 2b on the ridge portion 3, triethylgallium (TECa), arsine (AsH ₃ ), trimethylindium (TMI) and phosphine (PH ₃ ) are supplied at a predetermined flow rate, Wavelength 1.1μ
InGaP by forming a multi-quantum well structure by laminating an InGaAsP thin film having a composition of m and a thickness of 150Å and an InGaAs thin film having a thickness of 20Å for 4 to 6 periods.
An MQW light emitting layer 6 and a groove MQW layer 6a made of AsP / InGaAs are formed. Subsequently, the p-InP clad layer 7, the n-InP buried layer 8, the p-InP layer 9 and the p-InP layer
-InGaAsP contact layer 10 is sequentially grown (see FIG. 24D).

By this process, the emission wavelength can be controlled from about 1.3 μm to about 1.6 μm according to the values of the ridge width dw, the groove width dg, and the groove height h which are the shape factors of the semiconductor substrate. In this process, firstly p-InP
In order to form the current blocking layer 19, it is sufficient to previously form a reduction amount of the groove depth h in the groove depth of the semiconductor substrate. A p-electrode 11 and an n-electrode 12 are formed on a part of the contact layer on the ridge and on the semiconductor substrate side, respectively, to obtain a light emitting element chip (see FIG. 24E).

FIG. 25 shows the emission characteristics of the semiconductor light emitting device according to the present invention in a solid line. For comparison, the emission characteristics when the current blocking layer is not provided are shown by a broken line. As shown in FIG. 25, when the current blocking layer is provided according to the present invention, the threshold value of the injection current is lowered, the linearity is high, the luminous efficiency is improved and the output is increased, and the p-InP current blocking layer 19 is obtained. It has been confirmed that the introduction of the material improves the characteristics remarkably.

Example 12 Example of Introducing Buffer Layer Semiconductor Light Emitting Element In order to improve emission characteristics due to a damage layer generated when a non-flat semiconductor substrate is formed, an n-type buffer layer is formed on the non-flat semiconductor substrate. A manufacturing process for forming an InP thin film by crystal growth is shown in FIGS. In addition, in order to investigate the influence of the buffer layer and the ridge shape, the case where the buffer layer is formed in the reverse mesa shape together with the conventional forward mesa shape is also shown.

First, the oxide film 2 is formed on the n-InP substrate 1, and then a predetermined etching oxide film pattern for forming a non-flat semiconductor substrate is formed (see FIG. 26A).

Next, dry etching is performed by, for example, reactive ion etching (RIE) using chlorine gas, and the ridge portion 3 has a regular mesa shape on the n-InP substrate 1.
The groove 4 is formed, and a normal mesa type non-flat semiconductor substrate is manufactured. In addition, the n-InP substrate 1 is a bromine-based material such as 3HBr.
And a H ₂ O solution are used for wet etching to form an inverted-mesa type non-flat semiconductor substrate in which the ridge portion 3 has an inverted mesa shape (see FIG. 26B). After that, the oxide film 2 is removed.

The pressure is 70 Torr and the substrate temperature is about 600 ° C. to 700 ° C. by the metal organic chemical vapor deposition (MOVPE) method.
℃, trimethyl indium (TMI) and phosphine (P
H ₃ ) is supplied with selenium sulfide (H ₂ Se) as an n-type dopant to form the n-InP buffer layer 5 in an amount of 0.1 to 1.0 μm.
Grow about m. Continuously, triethylgallium (TE
Ca), arsine (AsH ₃ ), trimethylindium (TMI), and phosphine (PH ₃ ) are supplied at a predetermined flow rate and have a composition of wavelength of 1.1 μm and a film thickness of 150Å.
4 nGaAsP thin film and 20 Å thick InGaAs thin film
MQ consisting of InGaAsP / InGaAs by forming multiple quantum well structure by laminating about 6 periods
W light emitting layer 6 and groove MQW layer 6a are formed. Then, the p-InP clad layer 7, the n-InP buried layer 8,
p-InP layer 9, p-InGaAsP contact layer 10
Are sequentially grown (see FIG. 26C). Finally, the p electrode 11 and the n electrode 12 are formed on a part of the contact layer 10 on the semiconductor substrate side and on the ridge, respectively, to obtain a chip of a light emitting element (see FIG. 26D).

By this process, the ridge width (dw), the groove width (dg), and the groove height (h) which are the shape factors of the semiconductor substrate.
The emission wavelength can be controlled from 1.3 μm to 1.6 μm in accordance with the value of

FIG. 27 shows a characteristic example of the manufactured semiconductor light emitting device. It shows the relationship between the luminous efficiency η of the film thickness of the buffer layer and the wavelength shift amount. The luminous efficiency η does not depend on the mesa shape, and it greatly changes to the film thickness of the buffer layer regardless of the forward mesa shape or the reverse mesa shape, and by providing the buffer layer, it is possible to improve it by about 5 times as compared with the conventional characteristics. Recognize. This is because the thicker the buffer layer, the better the crystallinity.

If the wavelength range in which the emission wavelength is controllable is taken as the wavelength shift amount, the wavelength shift amount decreases sharply in the forward mesa structure as the thickness of the buffer layer increases, whereas in the reverse mesa structure, a comparison is made. It will be a gradual decrease. This decreasing tendency is due to the fact that the effective groove depth h becomes smaller when the buffer layer is grown, and the reverse mesa type has a larger capacity of the groove than the forward mesa type, and therefore the decreasing tendency is alleviated. FIG. 27
From the characteristics, it can be seen that the formation of the buffer layer and the inverted mesa ridge structure are effective for improving the light emission efficiency and the wavelength shift amount.

(Example 13) Example of semiconductor light-emitting device of introduction type of damage absorption layer When a non-flat semiconductor substrate was formed, especially when an oxide film was formed and dry etching (for example, chlorine RIE), the semiconductor substrate was damaged. If it enters, the quality of the crystal on it deteriorates, which causes deterioration of the characteristics of the light emitting device. In order to prevent this deterioration, a damage absorption layer is provided on the semiconductor substrate.

FIGS. 28A to 28D show a manufacturing process of a semiconductor light emitting device provided with a damage absorption layer. A film having a thickness of 0.1 to 0.5 μm is grown on the flat semiconductor substrate 1, and then a pattern of the oxide film 2 is formed (see FIG. 28A). After the damage absorption layer 20 and the semiconductor substrate are processed by dry etching, the oxide film 2 is removed (see FIG. 28B). After that, the damage absorption layer 20 is removed by selective etching using a sulfuric acid-based solution.
Crystal growth and electrode formation were performed by the same steps as described above to form a semiconductor light emitting device (see FIGS. 28C and 28D). Here, pattern formation and etching are performed so that the shape of the groove, especially the height (h) is only the semiconductor substrate.

By providing the damage absorption layer, it was confirmed that the light emitting efficiency of the semiconductor light emitting device was improved and the light output was increased due to the improvement of crystallinity.

As shown in Examples 11 to 13, according to the present invention, it is possible to realize a highly efficient light emitting device in which the emission wavelength can be easily controlled, and it is possible to realize a high density integrated optical functional device utilizing a wide wavelength band property. It is possible to achieve dramatic developments such as optical communication and optical measurement.

(Embodiment 14) FIG. 29 is a top view showing an optical integrated circuit according to an embodiment of the present invention. In this embodiment, the first wavelength is 1.3 μm and the second wavelength is 1.5 μm.
In the case of m, the optical communication system will be described by taking ping-pong bidirectional communication using light having a wavelength of 1.3 μm and broadcasting such as CATV using light having a wavelength of 1.5 μm. In the following description, 1.3 μm PD and 1.5 μm PD mean 1.3 μm light PD and 1.5 μm light PD,
Similarly, 1.3 μm LD means a LD for 1.3 μm light.

In FIG. 29, 41 is a Y-branch waveguide, 4
1a, 41b and 41c are waveguide portions, and 42 is 1.3 μm
Zone distributed feedback (DFB) semiconductor laser (LD), 43 is a monitor PD, 44 is a 1.3 μm PD, and 45 is a 1.3 μm
m residual light absorption region (layer), 46 is 1.5 μm PD, 47
Is a semiconductor substrate, 48 is an LD branch portion, and 49 is a PD branch portion.

To explain the outline of the operation, in 1.3 μm band ping-pong bidirectional optical communication, transmission and reception are performed in a time division manner, and transmission and reception are not performed at the same time. To do. For transmission of 1.3 μm light, laser light generated by the DFB laser (1.3 μm LD) 42 is guided through the Y-branch waveguide 41 and emitted from this integrated circuit. At this time, the power of the output light is equal to the monitor PD4.
Monitored by 3. Regarding the reception of 1.3 and 1.5 μm light, 1.3 μm incident on this integrated circuit
Light is guided in the straight portion of the Y-branching waveguide 41, and is branched into two waveguides at the Y-branching portion to travel. LD branch part 48
Although the light to enter the LD 42 is incident on the LD 42, it does not affect the transmission because the LD 42 is not operating at the time of receiving light of 1,3 μm. The light to the PD branch portion 49 is 1.3 μm PD4.
4 is absorbed and converted into photocurrent. The residual light that has not been absorbed is absorbed by the residual light absorption region 45, and is 1.5 μm.
Light of 1.3 μm does not enter the mPD 46. That is, the 1.3 μm residual light absorption region 45 is 1.3 μm
It is used as a wavelength filter that blocks light and transmits 1.5 μm light. When 1.5 μm light is incident, Y
The straight portion of the branch waveguide 41 is guided, and the Y branch portion branches into two waveguides. The light to the LD branch portion 48 is
Although incident on the 1.3 μm LDD 42, light in the 1.5 μm band is not absorbed by the active layer of the 1.3 μm LD 42, and therefore does not affect this LD. Light to the PD branch portion 49 is not absorbed by the absorption layer 45 having a composition of 1.3 μm.
Is transmitted to reach the 1.5 μm PD 46 and is converted into absorbed photocurrent.

Next, a method of manufacturing the present optical integrated circuit will be described.

First, basic crystal growth will be described below (see FIGS. 30 to 36).

(1-1) 1. On the n-InP substrate 10.
The waveguide layer 14 of 1 μm composition InGaAsP has a thickness of 0.3 μm.
m, the InP layer 5 is crystal-grown to 20 nm to obtain the structure of FIG.

(1-2) 1.3 μmLD (4 in FIG. 29)
The diffraction grating 13 having a pitch of 200 nm is formed in the region 2) (FIG. 31).

(1-3) 1.5 μm PD on the flat surface 21 (46 in FIG. 29) was formed by the above-described ridge forming method.
Ridge groove 4a with a groove width dg ₁ = 2 μm, a ridge 3a with a ridge width dw = 2 μm and a ridge height h = 2 μm
To form 1.3 μmLD and monitor PD, 1.3 μ
Each area which becomes mPD (42, 43, 4 in FIG. 29)
4), a ridge groove 4b having a groove width dg ₂ = 10 μm, a ridge 3b having a ridge width dw = 2 μm, and a ridge height h = 2 μm.
To obtain the structure of FIG.

(1-4) On the flat surface 21, effectively 1.
The multiple quantum well structure 17 having a band gap of 25 μm is crystal-grown. At this time, the wavelength shifts to the long wavelength side on the ridges 3a and 3b as described above, and on the ridge 3a having the groove width dg ₁ = 2 μm, the multiple quantum well structure 6 having the band gap of 1.5 μm and the groove width dg ₂ = 10μ
On the m ridge 3b, a multiple quantum well structure 6b having a band gap of 1.3 μm is formed (FIG. 33).

(1-5) 1.5 μm PD, 1.3 μm
LD, 1.3 μm PD portion is embedded and grown. This embedding can be preferably carried out by the method described in Japanese Patent Application Laid-Open No. 5-102607 (1993) (Japanese Patent Application No. 3-285470) by the present applicant. That is, FIG.
As shown in FIG. 4, Zn-doped p- using MOVPE method.
The InP current blocking layer 7 and the Se-doped n-InP current confinement layer 8 are sequentially grown. p-InP layer 7, n-In
The P layer 8 functions as a current confinement and optical confinement layer. At this time, the Se doping amount of the n-InP layer 8 is set to 5 × 10 ¹⁸ cm 2.
^{If it is -3} or more, the growth of the n-InP buried layer (current confinement layer) 8 on the upper part of the mesa structure (ridge) is suppressed, and only the p-InP current confinement layer grows on the ridge 6a or 6b. Subsequently, the p-InP overclad layer 9 and the p-InGaAsP layer 10 are successively MO-doped.
It grows by the VPE method.

(1-6) Y deposited at the time of embedding
The doped InP and the InGaAsP having a composition of 1.3 μm on the branch waveguides 41a, 41b and 41c are removed together with the p-InGaAsP layer as shown in FIG. 35 to form corresponding removed portions 22a, 22b and 22c, respectively. To do.

(1-7) Next, as shown in FIG.
An undoped InP layer 23 (1.000Å) is formed on each of the removed portions 22a, 22b and 22c formed in (1-6),
InGaAsP selective etching etch stop layer 24
(200 Å) and Andove InP layer 25 are sequentially grown.

With the above, crystal growth is completed.

Next, an electrode process is performed.

(2-1) 1.3 μmL D42, 1.3
A p-type electrode is formed using AuZnNi / Au on the μm PDs 43, 44, 45 and the 1.5 μm PD 46.

(2-2) The waveguide portion 41 is wet-etched on the stripe to the etch stop layer using a selective etching solution to form a ridge waveguide.

(2-3) An insulating film is deposited except the electrode portion.

(2-4) An electrode pad for attaching a wire is formed.

(2-5) The substrate is polished and A is applied to the substrate side.
The device is manufactured by forming the u electrode with uGeNi / Au.

Next, the characteristics of this element will be described.
FIG. 37 shows current-light output characteristics when an LD for 1.3 μm is oscillated. Threshold is 15mA, current is 3
An output of 4 mW is obtained at 0 mA. The side mode suppression ratio was 28 dB.

Next, the characteristics of PD will be described. 1.3
A reverse bias of 1 V is applied to the μm PD 44 and the 1.5 μm PD 46, and the 1.3 μm light residual light absorption region 35 is grounded so that the photocurrent generated by the residual light does not flow to another PD power source. From the left side of the waveguide 1.
Light of 1.3 μm and 1.5 μm was made incident from the side of the 3 μm PD44. At this time, in the 1.3 μm PD 44 and the 1.5 μm PD 46, 1.3 μm light,
Light of 1.5 μm is absorbed and photocurrent flows. 1.3 μm PD
The 1.3 μm light that was not absorbed by 44 is absorbed by the 1.3 μm light residual light absorption region 45, converted into photocurrent, and flows to the ground. As a result, almost no 1.3 μm light is incident on the 1.5 μm PD 46. FIG. 38 (A) shows the wavelength dependence of photocurrent and crosstalk of each PD.
It shows in (B). FIG. 38A shows the wavelength dependence of the crosstalk of the PD for 1.3 μm light, and FIG. 38B shows the wavelength dependence of the crosstalk of the 1.5 μm PD. The definition of the crosstalk c in this measurement is as follows.

[0200]

## EQU1 ## C _1.3 = 10 × log (1.3 μm PD photocurrent / _1.5 μm PD photocurrent) ... 1.3 μm band C _1.5 = 10 × log ( _1.5 μm PD photocurrent / 1.3 μm
(Photocurrent of mPD) ... 1.5 μm band As can be seen from FIGS. 38 (A) and 38 (B), good crosstalk characteristics of −24 dB are shown in both wavelength bands.

Further, when 1.3 μm light and 1.5 μm light are incident, the light is guided also to the LD branch portion, but at the time of 1.3 μm reception, it is not necessary to operate the LD, which has an influence. Can be ignored. Also, as described above, 1.5
Since the μm light does not affect the LD, it is 1.5
The characteristics of the LD do not change even when receiving μm light.

Although a DFB laser is used in this embodiment,
A distributed Bragg reflector (DBR) laser in which the diffraction grating is arranged on both sides of the active layer may be used.

Further, in this embodiment, the waveguide portion is 1.
The 1 μm composition was first grown on the substrate and used as a common waveguide. However, by optimizing the structure of the multiple quantum wells, the growth on the ridge was used, and the 1.1 μm composition to the 1.5 μm composition was used. It is possible to change the waveguide portion 41 (41a, 41b, 41c) to 1.3 μmP.
It may be grown together with D44, 45 and 1.5 μm PD46. That is, as shown in FIGS. 39A and 39B, the ridge groove 15 having a width corresponding to the PD 46 of 1.5 μm.
a, 1.3 μm PD44 and 1.3 μm residual light absorption region 4
Ridge groove 4b having a width corresponding to 5 and 1.1 μ waveguide portion 4
A multiple quantum well structure can be grown on a ridge formed with a ridge width 4c having a width corresponding to 1a, 41b, 41c. LD
Similarly for the branch portion, the Y branch waveguide 41 is set to 1.3 μm.
You may grow collectively with mLD42 and monitor PD43.

(Embodiment 15) An optical integrated circuit according to an embodiment of the present invention will be described with reference to FIG. 39A and 39B, the constituent elements are almost the same as those in the first embodiment, but the arrangement is different. In FIG. 40, 51 is an LD active layer having an effective band gap of 1.3 μm, 52 is a diffraction grating for forming a DBR laser, 53 is a DBR laser portion,
Reference numeral 54 is a curved waveguide, 55 is a 1.3 μm residual light absorption region, 56 is a 1.5 μm PD portion, 57 is a groove for blocking scattered light, and 58 is a semiconductor substrate.

The operation of this embodiment will be described. 1.3
The DBR laser 53 is used for transmission of μm. The resonator of this laser is formed by the cleavage plane of the semiconductor substrate and the diffraction grating 52. Since the reflectance of the diffraction grating is high, the laser light is mostly emitted from the left side of the element, and is not emitted to the PD side.

When the laser 53 is oscillated, spontaneous emission light is generated in addition to the laser light. Since this light is not guided light, the bending waveguide 54 is introduced, so that 1.5
Incident on the μm PD portion 56 can be avoided (FIG. 4).
0). Further, scattered light is generated when the light travels in the waveguide. These scattered lights can be prevented from entering the 1.5 μm PD portion 56 by the scattered light blocking groove 57. Due to these structures, the 1.5 μm PD portion 5 when transmitting 1.3 μm light
6 can be reduced.

On the other hand, when receiving 1.3 μm light, the laser 53 serves as a photodetector. Since the system in which this device is used is ping-pong bidirectional communication as described above,
Such usage is possible. The 1.3 μm light that has not been resonated by the laser / photodetector is absorbed in the 1.3 μm residual light absorption region 55 via the curved waveguide and does not enter the 1.5 μm PD portion 56. 1.5μ
At the time of m reception, the light is absorbed by the 1.5 μm PD portion 56 via the DBR laser (LD) portion 53, the curved waveguide 54, and the 1.3 μm residual light absorption region 55 and converted into a photocurrent.

The manufacturing method of this element is almost the same as that of the fourteenth embodiment. In addition, 1.3 μm LD and 1.3 μm PD
And the characteristics of 1.5 μm PD were the same as in Example 14.

As described above in detail with reference to Examples 14 to 15, according to the present invention, a semiconductor light emitting device,
A semiconductor photodetector, a semiconductor photodetector for detecting light having a wavelength longer than the detection wavelength, and a wavelength filter arranged between the photodetectors are integrated by coupling them through an optical waveguide. It can function as a wavelength transmitting element and a two-wavelength light detecting element.

(Embodiment 16) An embodiment of the present invention is shown in FIGS. 41 to 43. An InGaAsP layer 61 having a wavelength of 1.5 μm and a thickness of 2 μm is formed on the InP substrate 1, and a part of the InGaAsP layer 61 is subjected to reactive ion etching using chlorine gas to form two tapered groove portions 4d and a ridge. 3d is removed to form a structure as shown in FIG. On the front end face of the substrate 1, the ridge 3
The width of d is 5 μm, the width of the groove 4d is 10 μm, and on the rear end surface of the substrate 1, the width of the ridge 3d is 1.5 μm and the width of the groove 4d is 3 μm. The height of the ridge 3d is 2 μm, which is uniform over the entire surface of the substrate. Although a portion where the ridge 3d and the groove portion 4d are parallel to each other is formed near the rear end surface of the substrate 1, this parallel portion may not be formed. Conversely, a similar parallel portion may be provided near the front end surface of the substrate 1.

Next, the structure having the substrate 1 and the ridge 3d formed thereon is used as an epitaxial growth substrate, and a wavelength of 1.1 is obtained by an organic metal growth method.
An InGaAsP layer having a composition of μm and a thickness of 150 Å is formed to obtain a barrier layer 6d. This barrier layer 6d has 17Å In
The total thickness of the well layer 6e is about 0.3μ.
m quantum well structure 6 is grown, and the wavelength of 1.
An InGaAsP layer 62 having a composition of 35 μm is grown to 2 μm, and finally an InP layer 63 is grown to 2 μm. 42 and 43 show the cross-sectional shapes of the front end face and the rear end face of the grown element, together with an enlarged schematic view of the quantum well structure portion.

As described above, the width of the ridge 3d on the rear end face of the element is 1.5 μm, and the width of the groove 4d is 3 μm.
Since it is m, the band gap of the quantum well structure 6 is 1.0 μm at the rear facet of the device, as is clear from the ridge structure size-PL wavelength correlation diagram of FIG. Also, FIG.
3, the quantum well layer 6 on the side surface of the ridge 3d
Is thinner than the upper surface of the ridge 3d, the guided light is confined with the quantum well layer 64 having a thickness of about 0.3 μm and a width of about 1.5 μm as the core on the upper surface of the ridge 3d. The spot size is about 1.5 to 2 μm, which matches the spot size of the semiconductor optical device.

Similarly, the width of the ridge 3d on the front facet of the element is 5 μm and the width of the groove 4d is 10 μm as described above.
As is clear from the wavelength correlation diagram, the band gap of the quantum well structure 6 is 1.35 μm at the device front end face. As a result, the refractive index is substantially equal to or smaller than that of the layer 61 in which the ridge 3d is formed. Therefore, on the front facet of the device, the layer 6
1, 6 and 62 are core layers, and layers 1 and 63 are upper and lower clad layers. A buried ridge structure having a thickness of about 4.5 μm and a width of about 5 μm is formed. In this case, since the center of the core layer is in the layer 6, the guided light is not deviated from the axis, and from the confined state in the quantum well layer 64 at the device rear end face to the layers 61, 6, 62 at the device front end face. Move to a locked state. As a result, a waveguide having a spot size enlarged to 4 to 5 μm, which is similar to that of a fiber, is formed on the front end face of the device.

When a flat end fiber was coupled to the front end face of this element and the coupling loss was measured, it was 0.5 dB or less, and the connection tolerance was ± 2.4 μ with 1 dB tolerance.
It was m.

In the present embodiment, the ridge width at the front facet of the device was expanded to 5 μm. However, even if the ridge width remains constant, the spot size can be changed by changing the groove width as confirmed in FIG. There is a magnifying effect. This is because the refractive index difference between the core and the clad in the direction horizontal to the substrate surface at the front end face of the device is small, so that even if the core size is small, the guided light seeps out to the clad region and the effective spot size is enlarged. Because there is.

(Embodiment 17) FIGS. 44 to 46 show the second embodiment of the present invention. As a substrate for growing the quantum well layer, a structure similar to that of Example 16 is used, but as shown in FIG. 44, in this example, the diffraction grating 13 is formed on a part of the upper surface of the ridge 3d. . The layers 1 and 61 are doped with impurities so as to show n-type conduction. After growing the quantum well layer 6 in the same manner as in Example 1, the method proposed by Kondo et al.
No. 07), a p-type InGaAsP layer 65 is grown.

That is, after growing the quantum well layer 6,
A stripe mask (not shown) is formed only on the quantum well layer 64 located on the ridge 3d. Then, using a reactive ion etching (RIE) apparatus, the layer 6
4 is removed by etching away the quantum well layer 6 around 4
To the mesa structure. Then, the mask is removed.

Subsequently, on this, n-type InP or I
An nGaAsP layer 66 is grown, and finally p-type InGaA is grown.
The sP layer 62 and the InP layer 63 are grown, and the electrode layer 67 is further formed on a part of the uppermost surface.

As a result, a structure as shown in FIG. 46 is formed on the rear end face of the element. This is a laser structure using the n-type InP layers 1 and 63 as a current blocking layer, and functions as a DFB laser by forming electrodes on the upper and lower surfaces.

On the other hand, on the front facet of the device, the refractive index structure is almost the same as that of the sixteenth embodiment, so that it is a waveguide structure with an enlarged spot size.

Therefore, in this embodiment, the monolithic integration of the spot size expanding waveguide and the DFB laser can be obtained by one epitaxial growth.

In this embodiment, the layer 61 has a thickness of 4 μm,
A structure in which only 2 μm is processed to form a ridge may be used as a substrate, the layers 62 and 65 may be p-InP layers, and the layer 66 may be an n-InP layer. in this case,
The centers of the guided light spots on the front and rear end faces of the element are axially offset from each other, but the structure of the p-type cladding layer is simplified,
There is an advantage that the current confinement is effectively performed by the npn structure.

In this embodiment, when the diffraction grating 13 is not manufactured, it can be used as it is as a light receiving diode, so that a waveguide type photodiode having a high coupling efficiency with a fiber can be realized.

(Embodiment 18) An embodiment of the present invention is shown in FIGS. 47 to 49. The structure of this embodiment is similar to the structure of FIG. 44 to FIG. 46, but in this embodiment, the structure in which the ridge width and the groove width are changed is also provided on the rear facet of the element as compared with the case where it is near the front facet. FIG. 48 shows the cross-sectional structure of the front and rear end faces after epitaxial growth performed in the same manner as in the above-described embodiment, which is formed in the opposite direction, and FIG. 49 shows the cross-sectional structure of the central portion where the ridge width and groove width regions are narrow. Shown in. In the figure, the same components as those of the above-described embodiment are designated by the same reference numerals to simplify the description.

A non-reflective coating is applied to both end faces of the element having the above structure, and a current is injected into the electrode formed in the central portion, whereby a semiconductor optical amplifier with improved coupling efficiency with the fiber can be realized.

Furthermore, in this embodiment, by inverting the polarity of the applied voltage, it is possible to realize an optical modulator using the electron confined Stark effect.

In the examples, the waveguide of 1.5 μm light was explained using InGaAsP-based materials, but other materials
For example, it can be realized by using InAlGaAs system or both. Furthermore, similar effects can be realized by selecting the material system and composition in other wavelength bands such as 1.3 μm.

As described in Embodiments 16 to 18, according to the present invention, the spot size of the waveguide of the optical device can be enlarged by a simple manufacturing process, so that high performance and high reliability of the semiconductor optical device can be obtained. Economical integration can be realized.

[0229]

As described above, according to the present invention, a high-density integrated super luminescent photodiode is realized, and it is expected that the measurement or evaluation method making use of the high wavelength band property will be dramatically developed. .

According to the present invention, the semiconductor light emitting element, the semiconductor photodetecting element, the semiconductor photodetecting element for detecting light having a wavelength longer than the detection wavelength, and the wavelength filter arranged between the two photodetecting elements are provided through the optical waveguide. By combining and integrating them, they can be made to function as a 1-wavelength transmission element and a 2-wavelength photodetection element.

According to the present invention, since the spot size of the waveguide of the optical device can be enlarged by a simple manufacturing process, high performance and highly reliable integration of the semiconductor optical device can be economically realized.

[Brief description of drawings]

1A and 1B are process diagrams showing a procedure for forming a strained quantum well structure by a mask selective growth method, and FIG. 1C is a graph showing characteristics of emission wavelength with respect to mask width.

FIG. 2 is a perspective view showing a configuration of a conventional spot size exchanger.

FIG. 3 is a graph showing the composition of a strained quantum well structure and the characteristics of emission wavelength.

FIG. 4A is 1.55 μ formed on a non-flat substrate.
FIG. 3B is an example of the structure of an m-band light emitting device, FIG. 1B is a diagram showing a light emission characteristic simulation result of the structure of FIG. 1, and a solid line and a dotted line are diagrams showing a difference in crystallinity.

FIG. 5 is a perspective view of a substrate. (A) shows a state where an etching mask is formed, (B) shows a state where a selective growth mask is formed, and (C) shows a state where a groove is formed.

FIG. 6 is a graph showing a bandgap wavelength shift of a multiple quantum well structure on a ridge. (A) shows the influence of the ridge width, and (B) shows the influence of the ridge height.

FIG. 7 is a graph showing the dependence of the photoluminescence wavelength of a quantum well structure grown on a ridge substrate on the width of a ridge and a groove.

FIG. 8 is a graph showing the dependence of the photoluminescence wavelength of a quantum well layer structure grown on a ridge substrate on the height of the ridge.

FIG. 9 is a process for manufacturing an optical functional device according to a first embodiment of the present invention, in which (A) is a mask formation (for etching),
(B) is for mask formation (for selective growth), (C) is for non-flat substrate, (D) is for crystal growth (single growth), (E) is for crystal growth (buried growth), and (F) is for electrode formation. It is process drawing which shows each procedure.

10A and 10B are graphs showing changes in emission wavelength of a light emitting device according to Example 1 of the present invention. FIG. 10A shows changes in ridge width dw and emission wavelength, and FIG. 10B shows changes in groove width dg and emission wavelength.
(C) is a graph showing the change characteristics of the ridge height and the emission wavelength.

FIG. 11 is a graph showing the thickness characteristics of the InGaAs quantum well layer,
(A) shows ridge width dw and InGaAs quantum well layer thickness characteristics, (B) shows groove width dg and InGaAs quantum well layer thickness characteristics, (C) shows ridge height and InGaAs quantum well layer thickness characteristics. It is a graph which shows each.

FIG. 12 is an explanatory diagram of a ridge-forming substrate with a diffraction grating according to a second embodiment of the present invention, in which FIG.
(B) is a diffraction grating with an optical waveguide layer, and (C) is a side diffraction grating.

FIG. 13 relates to a method of manufacturing a four-wave integrated laser array (groove width modulation type) according to a third embodiment of the present invention, (A) is mask formation (for etching), and (B) is a non-flat substrate (groove width modulation). (Mold), (C) is crystal growth (molding of light emitting layer), (D) is crystal growth (embedded growth), and (E) is a process diagram showing each procedure of electrode formation.

FIG. 14 is a graph showing oscillation characteristics of a four-wave integrated laser array according to Example 3 of the present invention.

FIG. 15 relates to a method for manufacturing a four-wave integrated DFB laser array (groove width modulation type) according to Example 4 of the present invention, (A) forming a diffraction grating, (B) forming a mask (for etching),
(C) is a non-flat substrate (groove width modulation type), (D) is crystal growth (molding of light emitting layer), (E) is crystal growth (embedded growth), and (F) is a step showing each step of electrode formation. It is a figure.

FIG. 16 is a graph showing oscillation characteristics of a 4-wave integrated DFB laser array according to Example 4 of the present invention.

FIG. 17 relates to a method for manufacturing a four-wave integrated laser array (ridge width modulation type) according to a fifth embodiment of the present invention, (A) is mask formation (for etching), and (B) is a non-flat substrate (groove width modulation). (Mold), (C) is crystal growth (molding of light emitting layer), (D) is crystal growth (embedded growth), and (E) is a process diagram showing each procedure of electrode formation.

FIG. 18 is a schematic diagram of a monolithic heterodyne receiver according to the seventh embodiment of the present invention.

FIG. 19 is a superluminescent diode (groove width modulation method) according to Embodiment 8 of the present invention, (A) is mask formation (for etching), (B) is a non-flat substrate (groove width modulation type), 3C is a process diagram showing each procedure of crystal growth (formation of a light emitting layer), (D) crystal growth (embedded growth), and (E).

FIG. 20 is a graph showing an emission spectrum characteristic of the super luminescent diode according to Example 8 of the present invention.

FIG. 21 (A) relates to a super luminescent diode (ridge width modulation method) according to Embodiment 9 of the present invention.
Is for mask formation (for etching), (B) is for non-flat substrate (ridge width modulation type), (C) is for crystal growth (formation of light emitting layer), (D) is for mask formation (for etching), and (E) is for It is a flowchart showing each procedure of non-flat substrate formation before embedding.

FIG. 22 relates to a super luminescent diode (ridge height modulation method 1) according to Embodiment 10 of the present invention,
(A) mask formation (for selective growth), (B) non-flat substrate (after mask removal), (C) mask formation (for etching), D) non-flat substrate (ridge height modulation type), (E)
[Fig. 3] is a process drawing showing each procedure of crystal growth (formation of light emitting layer).

FIG. 23 is a super luminescent diode according to a modification of the tenth embodiment of the present invention (ridge height modulation method 2).
2A is a process diagram showing each procedure of mask formation (for selective growth), (B) non-flat substrate (after mask removal), and (C) mask formation (for etching).

FIG. 24 is a diagram showing an optical element manufacturing process (p-InP block layer introduction type) according to the eleventh embodiment of the present invention.

FIG. 25 is a characteristic (p of the optical element according to Example 11 of the present invention;
-InP block layer introduction type) FIG.

FIG. 26 is a diagram showing an optical element manufacturing process (buffer layer-introduced type) according to the twelfth embodiment of the present invention.

FIG. 27 is a characteristic (buffer layer-introduced type) diagram of the optical element according to Example 12 of the present invention.

FIG. 28 is a diagram showing an optical element manufacturing process (damage absorption layer introduction type) according to Example 13 of the present invention.

FIG. 29 is a schematic top view showing an optical integrated circuit according to Example 14 of the present invention.

FIG. 30 is a diagram for explaining the manufacturing method of the present invention, and a schematic cross-sectional view showing a state where a common waveguide and an n-InP layer are provided on the substrate.

31 is a diagram illustrating the manufacturing method of the present invention, and FIG.
It is a typical sectional view showing the state where a diffraction grating was provided in a part of n-InP layer of 0.

FIG. 32 is a view for explaining the manufacturing method of the present invention, and a schematic top view showing a state in which a ridge is formed.

FIG. 33 is a view for explaining the manufacturing method of the present invention, and a schematic cross-sectional view showing a state in which a multiple quantum well structure is provided.

FIG. 34 is a schematic cross-sectional view showing an embedded state.

FIG. 35 is a view for explaining the manufacturing method of the present invention, and a schematic cross-sectional view showing a state in which a doped InP layer and a multiple quantum well structure having a band gap of 1.3 μm are removed.

FIG. 36 is a diagram for explaining the manufacturing method of the present invention, which is a schematic cross-sectional view showing a state in which a removed portion is embedded.

FIG. 37 is a graph showing the current-light output dependence of 1.3 μm LD.

FIG. 38 is a graph showing wavelength dependence of photocurrent and crosstalk. (A) is 1.3 μm PD,
(B) shows the case of 1.5 μm PD.

FIG. 39 (A) is a schematic partial enlarged top view showing the width of a ridge groove of an optical integrated circuit, and FIG. 39 (B) is a schematic cross-sectional view showing the composition change of the quantum well structure of the part corresponding to (A). It is a figure.

FIG. 40 is a schematic top view showing an optical integrated circuit according to Embodiment 15 of the present invention.

FIG. 41 is a diagram showing a spot size conversion element according to Example 16 of the present invention and is a perspective view of a ridge-processed substrate before epitaxial growth.

FIG. 42 is a diagram showing a spot size conversion element according to Example 16 of the present invention, and is a sectional configuration diagram of the element in which a front end face of the element and a quantum well layer thereof are enlarged.

FIG. 43 is a diagram showing a spot size conversion element according to Example 16 of the present invention, and is a sectional configuration diagram of the element in which a rear end face of the element and a quantum well layer thereof are enlarged.

FIG. 44 is a diagram showing a spot size conversion element according to Example 17 of the present invention and is a perspective view of a ridge-processed substrate before epitaxial growth.

FIG. 45 is a diagram showing a spot size conversion element according to Example 17 of the present invention, which is a sectional configuration diagram of the element showing a sectional configuration of a front end face of the element.

FIG. 46 is a diagram showing a spot size conversion element according to Example 17 of the present invention, which is a sectional configuration diagram of the element showing a sectional configuration of a rear end face of the element.

FIG. 47 is a diagram showing a spot size conversion element according to Example 18 of the present invention and is a perspective view of a ridge processed substrate before epitaxial growth.

FIG. 48 is a diagram showing a spot size conversion element according to Example 18 of the present invention, which is a cross-sectional configuration diagram of the element showing a front end face configuration and a rear end face configuration of the device.

FIG. 49 is a diagram showing a spot size conversion element according to Example 18 of the present invention, which is a sectional configuration diagram of the element showing a sectional configuration of a central portion of the element.

[Explanation of symbols]

1 Substrate 2 Mask 2a Mask (stripe) 2b Oxide film 3 Ridge 3d Ridge 4 Groove (part) 4d Groove 5 Buffer layer 6 Active layer or Waveguide layer (light emitting part on ridge) 6a Groove MQW layer 6b Multiple quantum well structure 6d Barrier Layer 6e Well layer 6 _U Upper waveguide layer 6 _L Lower waveguide layer 7 Cladding layer 7'p-InP cladding layer 7a InP layer 8 Buried layer (current confinement layer) 9 p-InP layer 10 Contact layer 11 p Electrode 12 n Electrode 13 Diffraction Grating 14 Semiconductor Optical Waveguide Layer 15 Diffraction Grating 16 Separation Groove 16 a Separation Groove 17 Heat Sink 18 Lead Wire 19 p-InP Current Block Layer 20 Damage Absorption Layer 21 Flat Surfaces 22 a, 22 b, 22 c Removal Section 23 Undoped InP Layer 24 Etch stop layer 25 Undoped InP layer 41 Y branch waveguide 41a, 41b, 41c Waveguide Road portion 42 1.3 μm DFB semiconductor laser 43 Monitor PD 44 1.3 μm PD 45 1.3 μm Residual light absorption region (layer) 46 1.5 μm PD 47 Semiconductor substrate 48 LD branch portion 49 PD branch portion 51 LD active layer 52 Diffraction grating 53 DBR laser portion 54 Bent waveguide 55 1.3 μm Residual light absorption region (layer) 56 1.5 μm PD 57 Scattered light blocking groove 58 Semiconductor substrate 61 InGaAsP layer 62 InGaAsP layer 63 InP layer 64 Quantum well layer 65 InGaAsP layer 66 n -InP or InGaAsP layer 67 electrode layer dw ridge width dg groove width h ridge height

─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. 5-67032 (32) Priority date March 25, 1993 (March 25, 1993) (33) Country of priority claim Japan (JP) (31) Priority claim number Japanese Patent Application No. 5-327019 (32) Priority date December 24, 1993 (December 24, 1993) (33) Country of priority claim Japan (JP) (72) Inventor Mitsuru Naganuma 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo (72) Inventor, Yasuhiro Suzuki Yasuhiro Suzuki 1-1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo (72) Masahiro Yuda, Tokyo 1-6, Uchisaiwaicho, Chiyoda-ku, Nippon Telegraph and Telephone Corporation (72) Inventor Osamu Santomi 1-1-6, Uchisaiwaicho, Chiyoda-ku, Nippon Telegraph and Telephone Corporation (72) Inventor Kasaya Kasaya Tokyo 1-1-6 Uchisaiwaicho, Chiyoda-ku This Telegraph and Telephone Corporation (72) Inventor Junichi Nakano 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Kiyoyuki Yokoyama 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan (56) References JP-A 64-42888 (JP, A) JP-A-3-225884 (JP, A) JP-A-4-364084 (JP, A) JP-A-4-206982 ( JP, A) JP 61-183987 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01S 5/00-5/50 H01L 33/00 JISST file (JOIS)

Claims (21)

(57) [Claims] 1. A non-flat semiconductor substrate having a ridge shape, and an optical functional layer formed on the non-flat semiconductor substrate, the optical functional layer being selected from a light emitting layer, an absorption layer and an optical waveguide layer, The optical functional layer is an active layer having a multiple quantum well structure.
A functional layer, wherein the composition of the portion of the active layer on the ridge is different from the composition of the portion of the active layer other than the ridge. 2. The optical functional device according to claim 1, wherein the ridge shape has a ridge width of 1 μm to 10 μm, and
Ridge height from μm to 5 μm and from 1 μm to 10 μm
An optical functional element having a shape having a groove width of m. 3. The optical functional element according to claim 1, wherein the ridge has a diffraction grating on an upper surface or a side surface thereof. 4. The optical functional device according to claim 2, wherein the ridge width is from 1 μm to 5 μm, and crystals of several different compositions are grown in the cavity direction, and the ridge width is changed in series in the cavity direction. An optical functional element having the above-mentioned light emission or light reception characteristics. 5. The optical functional device according to claim 4, wherein the ridge has a diffraction grating depending on the composition, and a plurality of single lights are emitted from a single emission surface or the period of the diffraction grating. An optical functional element characterized by receiving light on a shorter wavelength side than the wavelength determined by. 6. The optical function element according to claim 4, wherein a light guide layer is provided in the ridge. 7. The optical functional element according to claim 2, wherein the ridge width is from 1 μm to 5 μm, and the ridge shape is such that the ridge width, the ridge height, or the groove width is continuously changed in a lateral direction. An optical functional element having different light emitting or light receiving characteristics depending on the location of the ridge shape which is changed in a series in the lateral direction. 8. The optical functional device according to claim 7, wherein a diffraction grating corresponding to the composition is provided on the upper portion of the ridge, and a single light is emitted in the parallel direction, or a wavelength determined by the period of the diffraction grating. An optical functional element characterized by receiving light of a shorter wavelength side. 9. The optical functional element according to claim 1, wherein the optical functional layer is a semiconductor light emitting layer, and a semiconductor thin layer having a conductivity type different from that of the non-flat semiconductor substrate in a groove portion of the non-flat semiconductor substrate. An optical functional element characterized by being formed with a film. 10. The optical functional element according to claim 1, wherein the optical functional layer is a semiconductor light emitting layer, and the non-flat semiconductor substrate is a non-flat semiconductor substrate in which the ridge shape of the light emitting layer is an inverted mesa structure. An optical functional element characterized in that 11. The optical functional element according to claim 1, wherein the optical functional layer is a semiconductor light emitting layer, and the non-flat semiconductor substrate is formed by forming a semiconductor thin film buffer layer on the non-flat semiconductor substrate. An optical functional element characterized by being a thing. 12. A non-flat semiconductor substrate having a ridge shape, and a plurality of optical functional elements according to claim 1 selected from a light emitting element or a light receiving element arranged on the non-flat semiconductor substrate, In an optical integrated device functionally combining the characteristics of each of the plurality of optical functional devices, the optical functional device has, as an active layer, a portion of a strained multiple quantum well layer formed monolithically, and An optical integrated device, wherein at least some of the plurality of optical functional devices have different compositions of the multiple quantum well layers on the ridge. 13. The optical integrated device according to claim 12, wherein the non-flat semiconductor substrate has a ridge width of 1 μm to 10 μm, a ridge height of 1 μm to 5 μm, and 1 μm.
An optical integrated device having a ridge shape with a groove width of 1 to 10 μm. 14. The integrated optical device according to claim 12, wherein a diffraction grating is provided on an upper surface or a side surface of the ridge of the non-flat semiconductor substrate. 15. The integrated optical device according to claim 14, wherein the diffraction grating has a period that varies depending on its position. 16. A method of manufacturing an optical functional device having a light emitting layer, an absorption layer or an optical waveguide layer, characterized by comprising the following steps: A ridge-shaped semiconductor substrate having a ridge width of 1 μm to 10 μm, and a ridge. A non-flat semiconductor substrate having a height of 1 μm to 5 μm and a groove width of 1 μm to 10 μm is prepared,
And a method of manufacturing an optical functional device, which comprises forming a strained multiple quantum well layer having different compositions on a portion on the ridge and a portion other than the ridge on the non-planar semiconductor substrate by a metal organic chemical vapor deposition method. 17. The method for manufacturing an optical functional element according to claim 16, wherein the non-planar semiconductor substrate is made non-planar after forming a thin semiconductor protective film layer having a composition different from that of the flat semiconductor substrate. A method for manufacturing an optical functional element, which is obtained by the above. 18. The method for manufacturing an optical functional device according to claim 16, wherein the ridge shape is set so that a multiple quantum well structure formed on the ridge has a desired composition, and the setting is performed. A method of manufacturing an optical functional device, wherein the optical characteristics of the optical functional device are determined by the composition of the obtained multiple quantum well structure. 19. The method of manufacturing an optical functional element according to claim 18, wherein the optical characteristic is a band gap or a refractive index of the multiple quantum well structure, and the ridge shape is set by setting the ridge width and the ridge height. And a groove width at least one of which is changed from one end side to the other end side of the waveguide on the ridge. 20. The method of manufacturing an optical functional element according to claim 18, wherein the optical characteristic is a light emitting or light receiving characteristic of the optical functional element, and the ridge shape is set by setting the ridge width, the ridge height size, and the ridge height. A method for manufacturing an optical functional element, characterized in that at least one of groove widths is changed in series in a vertical direction to thereby change the light emitting or light receiving characteristics in a cavity direction. 21. The method of manufacturing an optical functional element according to claim 18, wherein the optical characteristic is a light emitting or light receiving characteristic of the optical functional element, and at least one of the ridge width, the ridge height, and the groove width is lateral. A method for manufacturing an optical functional element, characterized in that the ridge shape is set so as to change in a series of directions to form an array-shaped optical functional element, and thereby the light emitting or light receiving characteristics are changed in the lateral direction.