JPH06275911A - Semiconductor laser device and its manufacture - Google Patents

Abstract

PURPOSE:To bury the side planes of a mesa stripe by a sufficiently high resistance burying layer by burying the side planes of the mesa stripe by an Fe doped semiconductor high resistance layer whose major ingredient is GaInP or Al Inks and changing the quantity of Fe dopant in response to the change of the burying growing planes in the vicinity of the mesa stripe. CONSTITUTION:A mesa stripe 10a whose longer side is in a (011) direction is formed on an n-type InP substrate 11a provided with a (100) plane. As for the mesa stripe 10a, an n-type InGaAsP guide layer 12a is formed on the substrate 11a by epitaxial growing and an undoped InGaAsP activating layer 13a is formed on the layer 12a. A p-type InP clad layer 14a and p-type InGaAsP contact layer 17a are formed on the activating layer 13a. The side planes of the mesa stripe 10a are buried by three types of Fe doped high-resistance InP burying layers 1, 2 and 3. The high-resistance InP burying layers 1, 2 and 3 are permitted to surround the planes differently at the time of growing and doping by the growing plane orientation is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device having an Fe-doped high-resistivity buried layer.
The present invention relates to a II-V compound semiconductor laser device.

With the development of optical communication technology, it is desired to further increase the communication capacity and the communication distance. Therefore, a high-power semiconductor laser capable of high-speed modulation is required. In order to meet such demands, it is desired to reduce the incidental capacitance and improve the luminous efficiency.

[0003]

2. Description of the Related Art As a semiconductor laser used for optical communication of 1.3 μm band and 1.5 μm band, a semiconductor laser using a high resistance buried layer as shown in FIGS. 9 and 10 is known. Hereinafter, a 1.5 μm band semiconductor laser will be described as an example.

In FIG. 9, a band gap wavelength of 1.3 μ is formed on an n-type InP substrate 121 having a (100) plane.
m, impurity concentration n = 1 × 10 ¹⁷ cm ⁻³ , thickness about 0.2 μm
m n-type InGaAsP guide layer 122 is formed,
It defines a lateral region.

An undoped InGa layer having a bandgap wavelength of 1.5 μm and a thickness of about 0.1 μm is formed on the guide layer 122.
An AsP active layer 123 is formed, and an impurity concentration p is formed thereon.
= 5 × 10 ¹⁷ cm ⁻³ , p-type InP clad layer 124 with a thickness of about 1.5 μm, bandgap wavelength 1.3 μm, impurity concentration p = 5 × 10 ¹⁸ cm ⁻³ , p with a thickness of about 0.2 μm A type InGaAsP contact layer 125 is formed.

These stacked layers on the InP substrate 121 are mesa-etched to the substrate, and the side surfaces of the mesa are filled with a Fe-doped high-resistance InP layer 126. The mesa stripe direction is set to the [011] direction. A p-side electrode 127 is formed on the front surface, and an n-side electrode 128 is formed on the back surface of the substrate to form a semiconductor laser device.

When a current is passed between the p-side electrode 127 and the n-side electrode 128, the carriers have high resistance InP buried layer 1 on both sides.
It passes through the central area bounded by 26. Here, the InP burying layer 126 fulfills the function of current confinement.

When radiative recombination of electrons and holes occurs in the active layer 123, light is generated, and the active layer 123 and the guide layer 1 are formed.
It is distributed in 22. The active layer 123 and the guide layer 122 have an n-type InP substrate 121 and a p-type InP clad layer 12 on the top and bottom.
4 and the left and right sides are sandwiched by the Fe-doped InP burying layer 126, so that an optical confinement effect occurs. Therefore, the laser light that is stimulated and emitted in the active layer 123 propagates in the active layer 123 and the guide layer 122.

FIG. 10 shows another structure of a semiconductor laser device according to the prior art. N-type InP having (100) plane
On the surface of the substrate 111, a band gap wavelength of 1.3μ
m, carrier concentration n = 1 × 10 ¹⁷ cm ⁻³ , thickness about 0.2
μm n-type InGaAsP guide layer 112, bandgap wavelength 1.55 μm, undoped InGaAsP active layer 113 having a thickness of about 0.1 μm, impurity concentration p = 5 × 10
^{A part of the 17} cm ⁻³ p-type InP clad layer 114 is formed, and these stacked layers are mesa-etched in the [011] direction.

Fe-doped high resistance In burying the side surface of the mesa
The P buried layer 116 is grown, and then the impurity concentration n = 5
An n-type InP burying layer 117 having a thickness of × 10 ¹⁸ cm ^-3 and a thickness of about 0.3 μm is grown.

After embedding the mesa side surface, p-type In is formed on the entire surface.
The remaining portion of the P-clad layer 114 is grown. p-type I
The total thickness of the nP clad layer 114 is about 1.5 μm. A p-type GaAsP contact layer 115 having a band gap wavelength of 1.3 μm, a carrier concentration p = 5 × 10 ¹⁸ cm ⁻³ and a thickness of about 0.2 μm is formed on the p-type cladding layer 114. The p-side electrode 118 is formed on the contact layer 115, and the n-side electrode 119 is formed on the lower surface of the substrate 111 to complete the semiconductor laser device.

In the structure of FIG. 10, the n-type InP buried layer 1 is formed on the Fe-doped high-resistance InP buried layer 116.
17 is formed, and the p-type clad layer 114 is also disposed thereon, which is different from the configuration of FIG. With this structure, the ability to supply current to the active layer 113 is enhanced, and the ability to block current to holes traveling to portions other than the active layer is enhanced by the n-type InP buried layer.

As described above, in the conventional semiconductor laser device including the mesa structure, the stripe direction of the mesa is [01
1] direction and the side surface of the mesa is buried with a high-resistance InP layer doped with Fe. The flow rate of Fe dopant at the time of forming the buried layer is constant. This dopant flow rate is
It was determined by the doping properties investigated with the (100) substrate.

On a (100) substrate, the amount of electrically activated Fe is about 6 × 1 at a growth temperature of 600 ° C., for example.
It saturates around 0 ¹⁶ cm ^-3 . Even if Fe is introduced above the saturation value, it will not be electrically activated and will not be activated F
There is concern that e may adversely affect the laser characteristics. Therefore, it has been considered that the Fe doping amount should be a value immediately before the saturation value.

[0015]

However, it is not always possible to obtain a region having a sufficiently high resistance with the Fe-doped InP high-resistance buried layer according to the conventional technique.

An object of the present invention is to provide a semiconductor laser device in which the side surface of the mesa is filled with a sufficiently high resistance buried layer. Another object of the present invention is to provide a method of manufacturing a semiconductor laser device in which the side surface of the mesa is filled with a high-resistance embedded Fe-doped layer having a sufficiently high resistivity to manufacture a semiconductor laser device.

[0017]

A method of manufacturing a semiconductor laser device according to the present invention comprises a step of forming a mesa stripe on a (100) plane III-V compound semiconductor substrate and GaInP or AlInAs on the side surface of the mesa stripe. And a buried growth step of burying with a Fe-doped semiconductor high resistance layer as a main component and changing the amount of Fe dopant according to the change of the burying growth surface near the mesa stripe.

The semiconductor laser device of the present invention is (1
InP substrate having a (00) plane, and a mesa stripe formed on the InP substrate along the [01-1] direction,
And a high resistance buried layer of Fe-doped InP that fills the side surface of the mesa stripe.

[0019]

The present inventor has discovered that the doping characteristics of Fe largely depend on the plane orientation of the growth surface on which the crystal grows.

In the side embedding of the mesa stripe,
The plane orientation of the growth surface changes as the growth progresses. By changing the Fe doping amount according to the change of the buried growth surface, good Fe doping can be performed at each stage of the buried growth.

When the mesa stripe is selected in the [01-1] direction, in the buried growth in which the side surface of the mesa is buried, (n
11) Side A appears. In these plane orientations, Fe
Is significantly higher than that for the (100) plane.

Therefore, the direction of the mesa stripe is [0
By selecting the [1-1] direction, it is possible to dope a high concentration of Fe, which has been impossible in the past.

[0023]

FIG. 1 schematically shows the structure of a semiconductor laser device according to an embodiment of the present invention. This semiconductor laser device
It is for emitting a laser beam having a wavelength of 1.55 μm.

N-type InP substrate 11 having (100) plane
A mesa stripe 10a long in the [011] direction on a
Are formed. In the mesa stripe 10a,
On the substrate 11a, the band gap wavelength of about 1.3 μm,
Pure substance concentration n = 1 × 10¹⁷cm ^-3, With a thickness of about 0.2 μm
Type InGaAsP guide layer 12a is formed epitaxially
Formed with a bandgap wavelength of 1.55 μm and thickness
Undoped InGaAsP active layer 13 having a thickness of about 0.1 μm
a is formed epitaxially.

Further, p-type InP having an impurity concentration p = 5 × 10 ¹⁷ cm ^-3 and a thickness of about 1.5 μm is formed on the active layer 13a.
The clad layer 14a and the bandgap wavelength of about 1.
3 μm, impurity concentration p = 5 × 10 ¹⁷ cm ⁻³ , thickness about 0.
A 2 μm p-type InGaAsP contact layer 17a is formed.

The mesa stripe 10 thus configured
The side surface of a has at least three types of Fe-doped high resistance In
It is buried by the P buried layers 1, 2, and 3. These high resistance InP buried layers 1, 2 and 3 have different plane orientations during growth, and doping is performed depending on the growth plane orientation. In the flat part, the thickness of the first buried layer 1 is about 1.2 μm and the thickness of the second buried layer 2 is about 0.5 μm.
μm, and the thickness of the third embedded layer 3 is about 0.3 μm.

A p-side electrode 21 is formed on the contact layer 17a and the buried layer 3, and an n-side electrode 22 is formed on the lower surface of the substrate 11a. Here, the embedding of the side surface of the mesa stripe will be considered with reference to FIG. In FIG. 2, the mesa stripe 10a extends in the [011] direction and has a (011) plane on its side surface.

In the side embedding of the mesa stripe,
Si on the upper surface of the mesa stripe used for normal mesa etching
Using the mask 18a of O ₂ or the like, epitaxial growth is performed by burying the mesa side surface by metal organic chemical vapor deposition (MOCVD).

For example, as source gases, trimethylindium (TMIn), triethylgallium (TEG)
a), phosphine (PH ₃ ) and arsine (AsH ₃ ) are used, and dimethyl zinc (DMZn) for p-type and silane (SiH ₄ ) for n-type are used as dopant gas. The growth conditions are a temperature of 600 ° C., a growth rate of 2 μm / hr,
V / III = 150.

As the mesa etching, either dry etching or wet etching may be used. When dry etching is used, it is desirable to perform light etching with a phosphoric acid-based solution or the like in order to remove the strained layer on the surface after dry etching.

At this time, the buried growth on the side surface of the mesa occurs on the side surface and the bottom surface of the mesa as shown in the figure, but the growth surface gradually approaches the (100) flat surface. That is, as the growth proceeds, the main growth planes are from (011) plane to (11
1) Go through the B side toward the (100) side.

Therefore, the inventor of the present invention used Fe
We investigated how the properties of doping change. FIG. 3 shows the plane orientation dependence of Fe doping. Ferrocene (Cp ₂ Fe) was used as the Fe dopant. In FIG. 3, the horizontal axis represents the flow rate of Cp ₂ Fe in sccm.
And the vertical axis represents the activated Fe density in InP × 10.
^The unit is ¹⁶ cm ^-3 . In the figure, (011) 5 ° off surface, (111) B 5 ° off surface, (311) B surface, (1
The curve of the Cd ₂ Fe flow rate dependence of the Fe density with respect to the (00) plane is shown.

On the (311) B plane, the rise (intake efficiency) of the Fe density is fast, but the Fe density is saturated soon. In the (100) plane, the rise of Fe density is slower than in the (311) B plane, but the saturation value is almost the same as that of the (311) B plane.

On the (111) B5 ° off-plane, the rise of the Fe density is slow, but the saturation of the Fe density hardly occurs. On the (011) 5 ° off surface, the rise of the Fe density is about the same as that on the (100) surface, but it does not saturate at the saturation concentration on the (100) surface, and the Fe density continues to rise.

Therefore, F in crystal planes of various plane indices
e Saturation concentration and F when flowing 10 sccm of Cp ₂ Fe
The amount of incorporation of e and the concentration of undoped impurities generated without impurity doping were examined. The measurement results are shown in FIG.

In FIG. 4, the horizontal axis represents the off angle from the (100) plane in the [01-1] direction, and the position of the principal plane index is indicated by an arrow. The vertical axis represents the concentration in cm ⁻³ . The Fe saturation concentration first decreases as it goes from the (011) plane to the (100) plane, reaches a minimum value in the vicinity of the (111) B plane, and then gradually rises.

The amount of Fe taken in is (1) from the (011) plane.
11) It decreases toward the B surface, then rises, takes a maximum value near the (311) B surface, and then decreases to reach the (100) surface.

The undoped impurity concentration is (011)
From the plane toward the (111) B plane and increases almost linearly, and then decreases sharply to the (211) B plane and (3
11) After taking a fairly low value in the vicinity of surface B, (1
It gradually rises toward the (00) plane.

Conventionally, a substantially constant dopant is supplied to the entire buried layer based on the saturation concentration of the (100) plane. For example, on the (111) B plane, the same Fe
Fe incorporation was much lower than the dopant flow rate, so Fe was not doped as expected, and
It is considered that the e concentration was low.

On the other hand, the undoped impurity concentration is
Since it is extremely high near the (111) B plane, (11
1) It is considered that the expected high resistance was not obtained near the B surface.

In order to make the entire buried layer have a resistance as high as possible, it is preferable to dope Fe until just before the saturation concentration. Since the Fe saturation concentration is high near the (011) plane, it is preferable to flow a large amount of Fe dopant,
Since the Fe incorporation efficiency is low near the (111) B plane, it is preferable to flow a large amount of Fe dopant.

On the other hand, (211) B plane and (3)
11) The Fe uptake efficiency is high near the B surface,
If the flow rate of Fe dopant is not limited, F above the saturation concentration
e is doped, and Fe that is not activated is generated. Therefore, with Fe doping based on the (100) plane, it is impossible to perform the best doping as a whole.

When the buried growth surface in the vicinity of the mesa is in the vicinity of the (011) plane to the (111) B plane, a Fe doping gas flow rate higher than an appropriate Fe doping gas flow rate considered on the basis of the (100) plane is used. In the vicinity of the (211) B plane to the (311) B plane,
F than the Fe dopant flow rate based on the (100) plane
It is preferable to reduce the e-dopant flow rate.

After the growth surface approaches the (100) plane, the flow rate of the Fe doping gas determined with the (100) plane as a reference may be used as usual. By performing such Fe doping, in the vicinity of the (011) plane,
A Fe concentration significantly higher than the conventional Fe concentration can be realized.

In the vicinity of the (111) B plane, the Fe concentration itself is not so high, but a significantly higher Fe concentration can be realized as compared with the conventional Fe concentration, and a high undoped impurity concentration is compensated for, resulting in a high resistance. Can be realized.

When increasing or decreasing the Fe doping amount, it is preferable to increase or decrease it by at least ± 20% or more, more preferably ± 50% or more.

FIG. 5 shows a method of manufacturing a semiconductor laser device according to an embodiment of the present invention. In FIG. 5A, (10
0) plane n-type InP substrate 11, n-type InGaAsP guide layer 12 and undoped InGa by MOCVD method.
AsP active layer 13, p-type InP clad layer 14, p-type I
The nGaAsP contact layer 17 is sequentially formed in this order. The thickness and the impurity concentration of each layer may be the same as those described with reference to FIG.

Next, as shown in FIG.
1] A SiO ₂ mask 18a having a width of about 2 μm and long in the direction is formed. Using this SiO ₂ mask 18a as an etching mask, a mesa having a height of about 2 μm and a width of about 1.5 μm and having substantially vertical sides is formed by using a sulfuric acid-based and hydrochloric acid-based etching solution. At this time, the (011) plane appears on the side surface of the mesa.

The mesa etching is performed until the substrate 11 is reached. In this way, under the mask 18a,
A mesa stripe 10a long in the [011] direction is formed. Next, as shown in FIG. 5C, the mesa stripe 1
Fe doped on the side surface of 0a by MOCVD method I
A high resistance buried layer 1 of nP is formed. For example, at a growth temperature of 600 ° C., a ferrocene flow rate of 100 sccm,
Grow 1.2 μm. Due to this growth, (01
Growth of the (1) plane and the (111) B plane is performed.

As is apparent from FIG. 3, 100s
The ferrocene flow rate of ccm is much higher than the flow rate (about 30 sccm) corresponding to the Fe saturation concentration for (100) plane InP. However, (011) to (111) B
In the vicinity of the surface, even at such a ferrocene flow rate, Fe
No concentration saturation occurs.

Next, as shown in FIG. 5D, a second high resistance buried layer is grown. The second high resistance buried layer 2 is formed with a ferrocene flow rate of 10 sccm.
By growing about 0.5 μm, (211) B
Surface, (311) B surface, etc. are grown. In these plane orientations, the uptake efficiency of Fe is high, and a sufficient amount of Fe is doped even at such a low flow rate.

If ferrocene of about 30 sccm corresponding to the saturation concentration of the (100) plane is flowed as in the conventional case, the saturation concentration is greatly exceeded, and Fe that is not activated is generated.

Next, as shown in FIG.
The third high resistance buried layer 3 near the 0) plane is formed by setting the ferrocene flow rate to 25 sccm. This ferrocene flow rate of 25 sccm corresponds to the amount of dopant immediately before the saturated Fe concentration on the (100) plane. At this time, the Fe concentration is about 5
The density is × 10 ¹⁶ cm ^-3, which is slightly lower than the saturation density of 6 × 10 ¹⁶ cm ^-3 .

After the mesa side surface is embedded and grown in this manner, the growth mask 18a is removed. Next, FIG.
As shown in (F), the n-side electrode 21 is formed on the upper surface of the growth surface and the p-side electrode 22 is formed on the lower surface of the substrate 11a.

In the semiconductor laser device manufactured in this manner, the high-resistance buried layer 1 in contact with the mesa stripe 10a is doped with a higher Fe concentration than the saturation concentration with respect to the (100) plane. Becomes

In the vicinity of the (011) plane, (100)
It is desirable to dope Fe with about 20% or more, preferably about 50% or more, more preferably about 100% or more of Fe saturation concentration with respect to the surface.

In the high resistance buried layer 2, Fe
Since the dopant flow rate is limited, F above the saturation concentration
Since e is not supplied, the adverse effect of inactivating Fe is prevented.

FIG. 6 shows the structure of a semiconductor laser device according to another embodiment of the present invention. N-type I having (100) plane
On the nP substrate 11b, a bandgap wavelength of about 1.3μ
m, impurity concentration n = 1 × 10 ¹⁷ cm ⁻³ , thickness about 0.2 μm
m n-type InGaAsP guide layer 12b, bandgap wavelength of about 1.55 μm, thickness of about 0.1 μm undoped InGaAsP active layer 13b, impurity concentration p = 5 × 10
^{A part of the 17} cm ⁻³ p-type InP clad layer 14b is formed, and the height is about 1.3 μm and the width is about 1.5 μm [01-1].
It is shaped into a mesa stripe 10b in the direction.

On the side surface of the mesa stripe in the [01-1] direction, an Fe-doped high-resistance InP burying layer 6 having a flat portion with a thickness of about 1.1 μm is buried, and further, an impurity concentration n = 5 × 10 5. An n-type InP buried layer 7 having a thickness of ¹⁸ cm ⁻³ and a flat portion thickness of about 0.3 μm is formed. The surface of the n-type InP burying layer 7 is almost a (100) plane.

On the n-type InP buried layer 7, p-type InP is formed.
The remaining portion of the clad layer 14b is formed, and p-type InP is formed.
The total thickness of the cladding layer is about 1.5 μm. p-type In
A bandgap wavelength of approximately 1.
3 μm, impurity concentration p = 5 × 10 ¹⁸ cm ⁻³ , thickness about 0.
A 2 μm p-type InGaAsP contact layer 17b is formed. On the contact layer 17b, the p-side electrode 21
And the n-side substrate 22 is formed on the lower surface of the n-type InP substrate 11b.

In such a structure, the (011) plane appears on the side surface of the mesa, but the (111) A plane and the (211) A plane are formed in the middle stage of the buried growth for embedding the side surface of the mesa.
A surface, such as surface (311) A surface, appears.

FIG. 7 shows the plane orientation dependence of Fe doping on each growth surface of such a mesa buried layer. Figure 4
Similarly, the horizontal axis represents the off angle in the [011] direction from the (100) plane, and the vertical axis represents the concentration in cm ⁻³ . In the figure, the Fe saturation concentration, the Fe uptake amount and the undoped impurity concentration when flowing 10 cc of ferrocene as the Fe dopant are plotted.

When compared with the respective values of the (100) plane, the Fe saturation concentration is higher by one digit or more in the other main planes. Further, the undoped impurity concentration does not show abnormality as in the (111) B plane and is always at a low level. The amount of Fe taken in has a peak in the vicinity of the (311) A plane and the (211) A plane, and gradually decreases toward the (100) plane and the (011) plane.

Therefore, the characteristic of the structure shown in FIG. 6 is that, in the mesa stripe embedding, in the region where the embedding growth surface extends from the (011) plane to the vicinity of the (311) A plane, the Fe concentration is (100) plane. The Fe saturation concentration can be made significantly higher.

Therefore, by adopting a Fe concentration at least 1.5 times, preferably 2 times, and more preferably one digit or more higher than the Fe saturation concentration of the (100) plane, an extremely high resistance mesa-embedded layer is formed. can do.

FIG. 8 is a schematic sectional view showing a method of manufacturing a semiconductor laser device according to an embodiment of the present invention. First, FIG.
N-type InP having (100) plane as shown in (A)
On the substrate 11, the n-type InGaAsP guide layer 12, the undoped InGaAsP active layer 13, and the part 15 of the p-type InP clad layer are continuously grown epitaxially by MOCVD.

Next, as shown in FIG.
SiO long in the [01-1] direction₂Forming the mask 18b
It Using this mask 18b as an etching mask, C
H_Four, H ₂Dry etch using a system etchant gas
Etching to reach the substrate 11b.
U In this way, the long mesast in the [01-1] direction
The lip 10b is formed.

Next, as shown in FIG. 8C, the side surface of the mesa stripe 10b is filled with the Fe-doped high-resistance InP buried layer 6 and the n-type InP buried layer 7. At this time, Fe
The doped high-resistance InP buried layer 6 is doped with a sufficient amount of Fe so as to have a sufficiently high resistance.

Next, as shown in FIG. 8D, the mask 1
8b is removed, and the remaining part 1 of the p-type InP clad layer is removed.
6b, and a p-type InGaAsP contact layer 17b is grown thereon. The p-type InP clad layer 15b
And 16b together form the p-type InP clad layer 14b.

Next, as shown in FIG. 8E, the p-side electrode 21 is formed on the contact layer 17b, and the n-side electrode 22 is formed on the lower surface of the substrate 11b to complete the semiconductor laser device. The composition, impurity concentration, thickness, etc. of each layer may be selected so as to realize the values described with reference to FIG. 6, for example.

Further, by setting the mesa stripe in the [01-1] direction, the undoped impurity concentration can be suppressed low, so that a high resistance can be realized without setting the Fe concentration too high.

The description has been made above by taking the case where the mesa stripe is formed on the InP substrate and the side surface of the stripe is filled with Fe-doped InP as an example. However, by doping Fe, the same crystal capable of forming a high resistance region. It is considered that the same effect can be obtained by the similar structure in AlInAs and GaInP having the structure.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to these. For example,
As long as the side surface of the mesa stripe is filled with the Fe-doped high-resistance buried layer, the configuration of the laser body, the oscillation wavelength, etc. are arbitrary.

It will be apparent to those skilled in the art that various other changes, improvements, combinations and the like can be made.

[0075]

As described above, according to the present invention,
Provided is a semiconductor laser device in which the side surface of a mesa stripe is filled with a high resistance burying layer having good properties.

Further, according to the present invention, there is provided a method of manufacturing a semiconductor laser device in which the side surface of the mesa stripe is filled with a buried layer having good high resistance characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor laser device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram for explaining buried growth of a mesa stripe.

FIG. 3 is a graph showing the plane orientation dependence of Fe doping.

FIG. 4 is a graph showing the plane orientation dependence of Fe doping.

FIG. 5 is a cross-sectional view showing the method of manufacturing the semiconductor laser device shown in FIG.

FIG. 6 is a sectional view of a semiconductor device according to another embodiment of the present invention.

FIG. 7 is a graph showing the plane orientation dependence of Fe doping.

8 is a cross-sectional view showing the method of manufacturing the semiconductor laser device shown in FIG.

FIG. 9 is a sectional view showing a configuration of a semiconductor laser device according to a conventional technique.

FIG. 10 is a sectional view showing a configuration of a semiconductor laser device according to a conventional technique.

[Explanation of symbols]

 1 1st InP: Fe high resistance burying layer 2 2nd InP: Fe high resistance burying layer 3 3rd InP: Fe high resistance burying layer 6 InP: Fe high resistance burying layer 7 n-type InP burying layer 10a [011] direction mesa stripe 10b [ 01-1] Direction mesa stripe 11 n-type InP substrate 12 n-type InGaAsP guide layer 13 InGaAsP active layer 14 p-type InP clad layer 17 p-type InGaAsP contact layer 21, 22 electrode

Claims (6)

[Claims] 1. A step of forming a mesa stripe (10a) on a (100) plane III-V compound semiconductor substrate (11a), and Fe doping containing GaInP or AlInAs as a main component on the side surface of the mesa stripe (10a). Of the semiconductor high resistance layer (1, 2, 3, 6), and changing the amount of Fe dopant according to the change of the buried growth surface in the vicinity of the mesa stripe. 2. The substrate is a (100) plane InP substrate, the mesa stripe is in the [011] direction, and the mesa stripe (10) is formed in the buried growth step.
a) The embedded growth surface near the side surface is mainly the (011) plane
When the (111) B plane is formed, the Fe dopant amount is set to (10
The method of manufacturing a semiconductor laser device according to claim 1, wherein the amount of Fe dopant in the vicinity of the (0) plane is increased. 3. In the buried growth step, when the buried growth surface near the side surface of the mesa stripe (10a) is mainly the (211) B surface to the (311) B surface, the Fe dopant amount with respect to the (100) surface vicinity is set. The method of manufacturing a semiconductor laser device according to claim 1, wherein the amount of Fe dopant is decreased. 4. A semiconductor laser device having a mesa stripe (10a) in the [011] direction on a (100) plane InP substrate (11a), wherein a side surface of the mesa stripe (10a) is embedded to form a side surface of the mesa stripe. F on the (100) plane in the contact area
Fe-doped InP having Fe concentration higher than saturation concentration
A semiconductor laser device having high resistance buried layers (1, 2, 3). 5. An InP substrate (11) having a (100) plane.
b) and [01-1] formed on the InP substrate (11b).
A semiconductor laser device comprising: a mesa stripe (10b) along a direction; and a Fe-doped InP high-resistance buried layer (6) buried in a side surface of the mesa stripe (10b). 6. The semiconductor laser device according to claim 5, wherein the high resistance buried layer (6) has a Fe concentration higher than a saturated Fe concentration on a (100) plane in a main part thereof.