JP3291447B2 - Semiconductor laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor laser device.

[0002]

2. Description of the Related Art Conventionally, AlGaInP-based semiconductor laser devices have been actively researched and developed as semiconductor laser devices having an oscillation wavelength in a red range. In particular, this AlGaInP-based semiconductor laser device can oscillate in the 630 to 680 nm band, and since this wavelength band has high visibility, such devices are used for laser pointers, line markers, and the like. Since the oscillation wavelength is shorter than that of the semiconductor laser device, it is expected as a light source for high density recording.

In such a semiconductor laser device, a GaAs layer is generally used as a current blocking layer.
OURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS,
VOL. 1, NO. 2, JUNE 1995, p723 to p727, shows an example in which a two-layer structure including an AlInP layer and a GaAs layer is adopted as a current blocking layer.

In this document, the semiconductor laser device having the current blocking layer of the two-layer structure has an oscillation threshold current and a slope efficiency higher than those of a general semiconductor laser device in which the current blocking layer has a single-layer structure of a GaAs layer. Have been reported to be improved.

[0005]

By the way, AlGaI
Regardless of the nP-based semiconductor laser device, the semiconductor laser device is required to further improve the oscillation threshold current and the slope efficiency.

Among them, the AlGaInP-based semiconductor laser device is inferior in characteristics of the oscillation threshold current and the slope efficiency due to a problem inherent to the material as compared with the AlGaAs-based semiconductor laser device, and further improvement in characteristics is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a semiconductor laser device having good characteristics of oscillation threshold current and slope efficiency.

[0008]

According to the present invention, there is provided a semiconductor laser device comprising: a first conductive type clad layer made of (Al _x1 Ga _1-x1 ) _y1 In _1-y1 P; and a first conductive type clad layer. An active layer formed on the active layer; a flat portion formed on the active layer;
And a striped ridge formed on the flat part
The conductivity type is opposite to the first conductivity type (Al _x2 Ga _1-x2 )
a cladding layer of a second conductivity type composed of _y2 In _1-y2 P, the
On the flat portion of the cladding layer of the second conductivity type and the ridge
A band gap (Eg) formed on the side surface of the portion and having an index of refraction smaller than that of the cladding layer of the second conductivity type and larger than the energy of oscillation light (hv: h is Planck's constant, ν is the frequency of oscillation light). : with a Eg> hν) (a
l _x3 Ga _1-x3 ) _y3 In _1-y3 P (1 ≧ x3>x1> 0,1
≧ x3>x2> 0, 1>y1> 0, 1>y2> 0, 1>
y3> 0), and a light confinement layer of the first conductivity type, wherein the thickness of the flat portion of the cladding layer of the second conductivity type is
1300 ° or less, and the impurity concentration of the light confinement layer is 5 × 10 ¹⁷ cm ⁻³ or less.

Such a semiconductor laser device has good characteristics of oscillation threshold current and slope efficiency.

Further, the semiconductor laser device of the present invention, (A
l _x1 Ga _1-x1 ) _y1 In _1-y1 P , a first conductivity type cladding layer, an active layer formed on the first conductivity type cladding layer, and a flat surface formed on the active layer. Part and the flat part
The first conductor having a stripe-shaped ridge portion formed.
(Al _x2 Ga _1-x2 ) _y2 In _1-y2
A second conductivity type cladding layer consisting of P, the second conductivity type
On the flat portion of the cladding layer and on the side surface of the ridge portion
Is formed on the second conductivity type cladding layer refractive index is smaller and more having a band gap of greater energy than the energy of the oscillation light _{(Al x3 Ga 1-x3)} y3 In 1-y3
P (1 ≧ x3>x1> 0, 1 ≧ x3>x2> 0, 1> y
1> 0, 1>y2> 0, 1>y3> 0), and a light confinement layer of the first conductivity type.
The thickness of the flat portion of the pad layer is 1300 ° or less, and the impurity concentration of at least the active layer side of the light confinement layer is 5 × 10 ¹⁷ cm ⁻³ or less.

Such a semiconductor laser device also has good characteristics of oscillation threshold current and slope efficiency.

In particular, the cladding layer of the second conductivity type is
The flat portion has a layer thickness of 800 ° or less.
Further, the layer thickness of the flat portion of the second conductivity type cladding layer
Is 100 ° or more.

[0013]

Further, an etching stop layer is provided between the flat portion and the ridge portion and on the flat portion.

In this case, since the flat portion can be formed with high precision, the production yield of a semiconductor laser device having good characteristics of oscillation threshold current and slope efficiency is improved.

In particular, the impurity concentration is 3 × 10 ¹⁷ cm
^-3 or less.

In this case, the characteristics of the oscillation threshold current and the slope efficiency become better.

Further, the impurity concentration is 2 × 10 ¹⁷ cm.
^-3 or less.

In this case, the characteristics of the oscillation threshold current and the slope efficiency are further improved.

The impurity concentration is 5 × 10 ¹⁶ cm
^-3 or more.

In this case, the entire light confinement layer or at least the active layer side of the light confinement layer can be formed as a low resistance region capable of having a sufficient carrier concentration. Since the current blocking effect is preferably obtained by the pn junction with the cladding layer, the characteristics of the oscillation threshold current and the slope efficiency can be improved.

Further, the impurity concentration is 7 × 10 ¹⁶ cm.
^-3 or more.

In this case, the entire light confinement layer or at least the active layer side of the light confinement layer can be formed as a low-resistance region having a more sufficient carrier concentration. Since the current blocking effect is preferably obtained by the pn junction with the layer, the characteristics of the oscillation threshold current and the slope efficiency can be improved.

Further, the impurity concentration is 1 × 10 ¹⁷ cm.
^-3 .

In this case, the oscillation threshold current becomes extremely small, and the slope efficiency becomes 0.5 W / A or less.
In addition, the pn between the low resistance region and the cladding layer of the second conductivity type.
It is very preferable because a sufficient current blocking effect can be obtained by bonding. The light confinement layer is doped with Se.
It is characterized by having been done.

Further, using a first conductivity type GaAs substrate as a substrate, a cladding layer of a first conductivity type cladding layer of the second conductivity type, the light confinement layer is substantially lattice matched with the GaAs substrate, respectively (Al _x1 Ga _1-x1 ) _0.5 In _0.5 P, (Al _x2
Ga _1-x2 ) _0.5 In _0.5 P, (Al _x3 Ga _1-x3 ) _0.5 In
_{Consists of 0.5} P.

In this case, the thickness of the flat portion is 0.01 to 0.5.
13 μm, preferably 0.03 to 0.08 μm, and the thickness of the light confinement layer is preferably 0.3 to 1 μm, preferably 0.4 to 0.85 μm, and more preferably 0.5 to 0.5 μm.
０．７0.75 μm. The light confinement layer is (Al _x3
In the case of Ga _1-x3 ) _y3 In _1-y3 P, since the ternary system has better thermal conductivity and the maximum effective refractive index than the quaternary system, the Al composition ratio x3 is most preferably 1. preferable.

In this case, the active layer is made of AlG
A single or multiple quantum well structure layer made of aInP or GaInP or a single layer that is a non-quantum well layer made of AlGaInP or GaInP is used.

Furthermore, a current blocking layer of a first conductivity type having a higher heat conduction efficiency than the light confinement layer is provided on the light confinement layer.

In this case, for example, the aforementioned (Al _x3 Ga _1-x3 )
_The optical confinement layer made of _y3In1-y3P has poor thermal conductivity,
Although there was a risk of deteriorating the oscillation threshold current and the like, the thickness of the light confinement layer was reduced to suppress the reduction of the heat dissipation effect, and the current blocking layer could sufficiently secure the current blocking effect and also supplement the heat dissipation effect. .

In particular, a current blocking layer of a first conductivity type having a higher impurity concentration (ie, a higher carrier concentration) than the light confinement layer is provided on the light confinement layer.

In this case, the function of the light confinement layer as a current blocking layer is that the current blocking effect may be reduced because the impurity concentration (carrier concentration) is low, but the current blocking layer has a large impurity concentration (carrier concentration). The layer can sufficiently compensate for the current blocking effect.

The first conductivity type current blocking layer preferably has a band gap of energy smaller than the energy of the oscillating light.

Particularly, the current blocking layer is made of GaAs.

In this case, GaAs is not liable to be oxidized, has a favorable advantage in manufacturing, and has an AlGaInP
It is preferable because it has better thermal conductivity than AlInP or the like.

Further, the carrier concentration of at least the active layer side of the light confinement layer is about 5 × 10 ¹⁶ cm ⁻³ or more.

In this case, at least the active layer side of the optical confinement layer can be a low resistance region, and a current blocking effect can be preferably obtained by a pn junction between this region and the second conductivity type cladding layer. And the characteristics of slope efficiency can be improved.

In particular, the light confinement layer is a low resistance layer.

In this case, the light confinement layer is a low resistance layer, and the current blocking effect by the pn junction with the second conductivity type cladding layer is preferably obtained, so that the characteristics of the oscillation threshold current and the slope efficiency are remarkably good. become. The carrier concentration of the low resistance layer is preferably approximately 5 × 10 ¹⁶ c
m ⁻³ or more, more preferably about 1 × 10 ¹⁷ cm ⁻³ or more.

The above layers are preferably formed by MOCVD.
It is formed by a vapor phase growth method such as a method or an MBE method.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention, Al
A GaInP-based semiconductor laser device will be described with reference to the drawings.
1 and 2 are a schematic cross-sectional structure diagram of the semiconductor laser device and a schematic band structure diagram in the vicinity of the active layer or the current block layer, respectively.

In the figure, reference numeral 1 denotes an n-type GaAs semiconductor substrate whose one main surface (crystal growth surface) extends from the (100) plane to [011].
In the direction θ (θ = 5 to 17 degrees, preferably 7 to 1
3 degrees: this angle θ is hereinafter referred to as an off-angle θ), and an n-type Ga _0.5 In _0.5 P buffer layer 2 having a thickness of 0.3 μm is formed on the one main surface.

On the buffer layer 2, a layer thickness of 1.2 μm
Of n-type _{(Al x1 Ga 1-x1)} 0.5 In 0 .5 P ( in this embodiment x
1 = 0.7: Si doping) is formed.

As shown in detail in FIG. 2, on the n-type cladding layer 3, an undoped (Al _z1 G
a _1−z1 ) _0.5 In _0.5 P (in this embodiment, z1 = 0.5), the light guide layer 4 is formed.

On this light guide layer 4, a layer having a thickness of 100
It has tensile strain (Al_pGa_1-p) _qIn_1-qP (1> p
≧ 0, 1> q> 0.51: In the present embodiment, p = 0, q = 0.
65) Compression of quantum well layers 5a, 5a, 5a and layer thickness 40 °
With distortion (Al_rGa_1-r)_sIn_1-sP (1 ≧ r>
0, 0 <s <0.51: r = 0.5, s =
0.45) The quantum barrier layers 5b and 5b are alternately stacked
Of undoped strain-compensated multiple quantum well structures
The active layer 5 is formed.

An undoped (Al _z2 Ga _{1 -z 2} ) _0.5 In _0.5 P (in this embodiment, z 2 = 0.5) light guide layer 6 having a thickness of 500 ° is formed on the active layer 5.

On the light guide layer 6, a flat portion 7a having a layer thickness t and a height of approximately 0.5 to 0.8 μm extending substantially in the center of the flat portion in a direction perpendicular to the plane of the drawing (resonator length direction). Top width 2.5
P-type (Al _x2 Ga _1-x2 ) composed of a stripe-shaped ridge portion 7b having a width of 3.5 to 4.5 μm and a lower width of 3.5 to 4.5 μm.
_0.5 In _0.5 P (x2 = 0.7: Zn-doped in this embodiment)
Is formed.

On the upper surface of the ridge portion 7b, a layer thickness of 0.1 μm is formed.
m p-type Ga _0.5 In _0.5 P cap layer (Zn doped)
8, and a 0.3 μm-thick p-type GaAs cap layer (Z
n-deep) 9 is formed in this order.

The p-type cap layers 8 and 9 and the ridge 7
b on the side surface and the flat portion 7a, an n-type
(Al_x3Ga_1-x3)_0.5In_0.5P (1 ≧ x3> x1, x
2> 0: x3 = 1 in this embodiment, Se-doped)
Impurity concentration is 5 × 10¹⁷cm ^-3Current block layer below
Confinement that also functions as a light source and has a light confinement function
The layer 10 and the light confinement layer 10 have better thermal conductivity and
In this embodiment, the impurity concentration is 1 × 10¹⁸cm^-3
N-type GaAs (Se-doped) with a layer thickness of 0.3 μm
Current block layers 11 are formed in this order.
You.

The cap layer 9 and the current block layer 11
On the top, a 5 μm-thick p-type GaAs contact layer (Zn
Dope) 12 is formed.

The upper surface of the contact layer 12 is made of Au-Cr.
The p-type ohmic electrode 13 made of n-type GaAs
On the lower surface of the s substrate 1, an n-type ohmic electrode 14 made of Au-Sn-Cr is formed.

In this semiconductor laser device, crystal growth of each layer is performed by a conventionally known metal organic chemical vapor deposition (MOCVD) method, but other molecular beam epitaxy (MB) is used.
A vapor phase growth method such as E method) is also possible.

Such a semiconductor laser device is sandwiched between the cladding layers 3 and 7 having a band gap larger in energy than the band gap of the active layer 5 (that is, the energy (hν) of the oscillation light) and the energy (hν) of the oscillation light. Larger band gap (ie, little absorption of oscillation light)
And a light confinement layer 10 having a smaller refractive index than the cladding layer 7
And a current blocking layer 11 having better thermal conductivity than the light confinement layer 10. The light confinement layer 10
Is of the same conductivity type as the cladding layer 7 or undoped, the current blocking effect and the current confinement effect are weakened,
Oscillation threshold current and slope efficiency deteriorate, so do not set them.

The semiconductor laser device of this embodiment operates as a real refractive index guided laser device by the configuration of the light confinement layer 10 which is transparent to the oscillation light. In order to operate as an index-guided type, the actual refractive index difference between the active layer 5 below the ridge portion 7b region and below the ridge portion 7b region needs to be a predetermined value or more. In order to operate satisfactorily, preferably, the difference in refractive index is required to be 3 × 10 ⁻³ or more.

FIG. 3 shows the relationship between the thickness t of the flat portion 7a and the actual refractive index difference between the active layer 5 under the ridge portion 7b and the portion outside the ridge portion 7b.

From FIG. 3, in the present embodiment, the layer thickness t of the flat portion 7a is set so that the actual refractive index difference becomes 3 × 10 ^-3 or more.
Is selected to be 1300 ° or less, and preferably 800 ° or less which is 5 × 10 ⁻³ or more. And the active layer 5
Alternatively, in a structure in which the light confinement layer 10 is in direct contact with the light guide layer 6, there is an inconvenience such that the layers are exposed to the air during manufacturing. Therefore, the lower limit of the layer thickness t is preferably, for example, about 100 °.

FIG. 4 shows the relationship between the thickness u of the optical confinement layer 10 of the semiconductor laser device of the present embodiment and the oscillation threshold current obtained by experiments. Note that this characteristic is such that the impurity concentration of the optical confinement layer 10 is 1 × 10 ¹⁷ cm ⁻³ , and the cavity length L =
It was obtained by continuous oscillation under the conditions of 400 μm, uncoated end face, and room temperature.

From FIG. 4, the thickness u of the optical confinement layer 10 is
It is understood that the thickness is preferably 0.3 μm or more and 1 μm or less, more preferably 0.4 μm or more and 0.85 μm or less, and more preferably 0.5 μm or more and 0.75 μm or less.

The reason why the light confinement layer 10 needs to have a certain thickness is as follows. That is, in the present embodiment, since the current blocking layer 11 is made of a material capable of absorbing light, if the thickness of the light confinement layer 10 is small, light is strongly absorbed by the current blocking layer 11 and if the thickness is too large, This is because the light confinement layer 10 has poor heat dissipation, and the heat dissipation characteristics of the element are poor.

FIG. 5 is a current-light output characteristic diagram (IL characteristic) of the semiconductor laser device of the present embodiment and a loss guide type AlGaInP-based semiconductor laser device in which the conventional current blocking layer has a single-layer structure of a GaAs layer. Figure). Note that this characteristic also shows that the impurity concentration of the optical confinement layer 10 is 1 × 10 ¹⁷ c
m ⁻³ , resonator length L = 400 μm, u = 0.5 μm, t =
It was obtained by continuous oscillation under the conditions of 0.05 μm, uncoated end face, and room temperature.

From FIG. 5, it can be seen that the device of this embodiment has a smaller oscillation threshold current value and better slope efficiency than the conventional device.

Next, FIG. 6 shows the relationship between the impurity concentration (dopant concentration) of the light confinement layer 10, the oscillation threshold current, and the slope efficiency.

It can be understood from FIG. 6 that, as the impurity concentration of the optical confinement layer 10 decreases, the oscillation threshold current decreases and the slope efficiency increases.

In particular, when the impurity concentration of the light confinement layer 10 is 5
In the case of × 10 ¹⁷ cm ⁻³ or less, a loss guide type AlGaI in which the conventional current blocking layer has a single-layer structure of a GaAs layer.
The oscillation threshold current can be reduced to 40 mA or less, which is smaller than the oscillation threshold current of the nP-based semiconductor laser device, and the slope efficiency can be increased to 0.3 or more, which is larger than that of the conventional device.

Further, when the impurity concentration is 3 × 10 ¹⁷ cm ^-3
In the following cases, the oscillation threshold current can be made smaller than 30 mA, and the slope efficiency can be made larger than 0.4, which is more preferable. In the case of 2 × 10 ¹⁷ cm ⁻³ or less, the oscillation threshold current is made smaller than 25 mA. , Slope efficiency is 0.4
It is more desirable because it can be larger than 5. In addition, 1 × 1
When it is 0 ¹⁷ cm ⁻³ or less, the oscillation threshold current becomes extremely small, and the slope efficiency becomes 0.5 or more.

Further, the impurity concentration is 1 × 10 ¹⁷ cm.
^-3 , the oscillation threshold current becomes extremely small, the slope efficiency becomes 0.5 W / A or less, and a sufficient current flows due to the pn junction between the low resistance region and the second conductivity type cladding layer. This is most preferable because a blocking effect can be obtained.

As described above, it can be seen that as the impurity concentration of the light confinement layer 10 decreases, the oscillation threshold current and the slope efficiency improve.

This is because, in the conventional device, the current is blocked by the pn junction formed by the current blocking layer having the opposite conductivity type to the cladding layer and the like adjacent to the current blocking layer. This is exactly the opposite of what was considered desirable at high concentrations.

Although the reason is not sufficient, in the case of the semiconductor laser device of the present invention, the light confinement layer 10 having a larger band gap (larger Al composition ratio) than the cladding layer 7 easily moves impurities (dopant). This is probably because impurities (dopant: Se in this embodiment) from the layer 10 diffused toward the active layer 5 side. In addition, it is considered that one of the causes of the device of the present invention is that the layer thickness t of the flat portion is smaller than that of the conventional semiconductor laser device.

When the impurity concentration (carrier concentration) of the optical confinement layer 10 becomes very small, the current blocking effect and the current pinching effect due to the pn junction with the cladding layer 7 are weakened, and the oscillation threshold current is reduced. The impurity concentration is preferably larger than 2 × 10 ¹⁶ cm ⁻³ because the slope efficiency becomes poor.
Preferably, it is 5 × 10 ¹⁶ cm ⁻³ or more. In the above-described embodiment, the activation rate of the dopant is approximately 100%. Therefore, when the impurity concentration is 2 × 10 ¹⁶ cm ⁻³ , the carrier concentration is approximately 2 × 10 ¹⁶ cm ^−3. Concentration 5
The carrier concentration in the case of × 10 ¹⁶ cm ^-3 is approximately 5 × 10 ¹⁶ c
m ⁻³ , the impurity concentration is 7 × 10 ¹⁶ cm ⁻³ , the carrier concentration is approximately 7 × 10 ¹⁶ cm ⁻³ , and the impurity concentration is 1 × 10 ¹⁷ c
The carrier concentration in the case of m ⁻³ corresponds to approximately 1 × 10 ¹⁷ cm ⁻³ .

The current blocking layer 11 may be made thicker than the light confinement layer 10 which also functions as a current blocking layer, so that the current blocking effect is increased.

Further, in the above description, the active layer having the strain compensation type quantum well structure has been mainly described. However, the active layer may have a tensile strain or a compressive strain, may have no strain, and may have a bulk structure. Further, the above-described active layer has a light guide layer for improving light confinement in the quantum well layer, but a configuration without such a light guide layer is also possible.

[0073] Further, may be used n-type GaAs buffer layer in place of the n-type GaAs semiconductor substrate 1 and the n-type cladding layer 3 n-type is provided between the Ga _{0. 5} In _0.5 P buffer layer 2,
Further, the buffer layer may not be provided.

In the cladding layer composed of the ridge portion and the flat portion as described above, for example, an etching stop layer is provided between the two portions, and a saturable light absorbing layer such as a saturable light absorbing layer is provided in the flat portion or the ridge portion. May be included.

Further, (Al _x Ga _{1 -x} ) _y In _{1 -y} P (x ≧
0) The crystal is lattice-matched exactly with the GaAs semiconductor substrate when y = 0.51, and no distortion occurs, but almost no distortion occurs near y = 0.51, so that (Al _x G
a _1-x ) _0.5 In _0.5 P is abbreviated to the composition ratio y.
May be around 0.51. In particular, in the present invention, it is preferable that the clad layer and the block layer have substantially no distortion.

Further, in the above-described embodiment, one main surface of the GaAs semiconductor substrate 1 is a surface inclined in the [011] direction from the (100) plane. That is, one main surface (crystal growth surface) of the GaAs substrate
Are planes inclined from the (100) plane in the [0-1-1] direction, planes inclined from the (010) plane in the [101] or [-10-1] direction, and [110] or [110] from the (001) plane. [−
1-10], ie {100}.
Any surface may be used as long as it is inclined from the surface in the <011> direction.

[0077]

In addition, in the above embodiment, the entire layer
Impurity concentration is 5 × 10¹⁷cm^-3Light confinement is
Layer, but at least the impurity concentration on the active layer side is 5 ×
10 ¹⁷cm^-3The following optical confinement layers can also be used.
You. Furthermore, the impurity concentration in the optical confinement layer is gradually increased.
It can be changed stepwise, and the light confinement layer
It may be composed of a plurality of layers having different composition ratios.

[0079]

[0080]

The present invention can provide a semiconductor laser device having good characteristics of oscillation threshold current and slope efficiency.

[Brief description of the drawings]

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

FIG. 2 is a schematic band structure diagram near an active layer or a current block layer of the semiconductor laser device according to the embodiment.

FIG. 3 is a diagram illustrating a relationship between a layer thickness t of a flat portion of a p-type cladding layer and an actual refractive index difference.

FIG. 4 is a diagram illustrating a relationship between a thickness u of an optical confinement layer and an oscillation threshold current.

FIG. 5 is a diagram showing a relationship between light output and current characteristics of the semiconductor laser device of the embodiment and a conventional semiconductor laser device.

FIG. 6 is a diagram showing a relationship between an impurity concentration of an optical confinement layer, an oscillation threshold current, and a slope efficiency.

[Explanation of symbols]

Reference Signs List 1 n-type GaAs semiconductor substrate 3 n-type (Al _x1 Ga _1-x1 ) _0.5 In _0.5 P cladding layer 5 active layer 7 p-type (Al _x2 Ga _1-x2 ) _0.5 In _0.5 P cladding layer 7 a flat portion 7 b ridge portion 10 Optical confinement layer (n-type (Al _x3 Ga _1-x3 ) _0.5 In
_0.5 P layer) 11 Current block layer (n-type GaAs layer)

──────────────────────────────────────────────────の Continuing on the front page (72) Koji Yoneda, Inventor 2-5-2-5, Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Masayuki Shono 2-5-2, Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Akira Ibaraki 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Keiichi Yoshinori 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (56) References JP-A-8-321656 (JP, A) JP-A-8-130344 (JP, A) JP-A-5-37078 (JP, A) IEEE Journal on S Selected Topics in Quantum Electronics, 1 [2] (1995), p. 723-727 14th IEEE Int. Semicon. Laser Conf. , (1994), p. 243-244 Th3.5 (58) Field surveyed (Int. Cl. ⁷ , DB name) H01S 5/00-5/50 JICST file (JOIS)

Claims (16)

(57) [Claims] 1. A first conductive type clad layer made of (Al _x1 Ga _1-x1 ) _y1 In _1-y1 P, an active layer formed on the first conductive type clad layer, and the active layer Flat formed on
A ridge portion formed on the flat portion and the flat portion;
(Al _x2 G)
a _1-x2 ) _y2 In _1-y2 P cladding layer of the second conductivity type, and above and before the flat portion of the cladding layer of the second conductivity type
It is formed on the side surface of the ridge portion and has a band gap of an energy smaller than that of the cladding layer of the second conductivity type and larger than that of the oscillation light (Al _x3 G
a _1-x3 ) _y3 In _1-y3 P (1 ≧ x3>x1> 0, 1 ≧ x3
>X2> 0, 1>y1> 0, 1>y2> 0, 1>y3>
0) a first conductivity type light confinement layer made of, includes a front
The flat portion of the second conductivity type cladding layer has a thickness of 130.
0 ° or less, and the impurity concentration of the light confinement layer is 5 °.
The semiconductor laser device characterized by × is 10 ¹⁷ cm ^-3 or less. 2. A first conductive type cladding layer made of (Al _x1 Ga _1-x1 ) _y1 In _1-y1 P, an active layer formed on the first conductive type cladding layer, and the active layer. Flat formed on
A ridge portion formed on the flat portion and the flat portion;
(Al _x2 G)
a _1-x2 ) _y2 In _1-y2 P cladding layer of the second conductivity type, and above and before the flat portion of the cladding layer of the second conductivity type
It is formed on the side surface of the ridge portion and has a band gap of an energy smaller than that of the cladding layer of the second conductivity type and larger than that of the oscillation light (Al _x3 G
a _1-x3 ) _y3 In _1-y3 P (1 ≧ x3>x1> 0, 1 ≧ x3
>X2> 0, 1>y1> 0, 1>y2> 0, 1>y3>
0) a first conductivity type light confinement layer made of, includes a front
The flat portion of the second conductivity type cladding layer has a thickness of 130.
0 ° or less, and the impurity concentration of at least the active layer side of the light confinement layer is 5 × 10 ¹⁷ cm ⁻³ or less. 3. The flatness of the cladding layer of the second conductivity type.
The layer thickness of the portion is 800 ° or less.
3. The semiconductor laser device according to 1 or 2 . 4. The flatness of the cladding layer of the second conductivity type.
The layer thickness of the portion is 100 ° or more.
4. The semiconductor laser device according to 1, 2, or 3 . 5. The semiconductor device according to claim 5 , wherein a gap between said flat portion and said ridge portion is provided.
Having an etching stop layer on the flat portion.
The semiconductor laser device according to claim 1, 2, 3, or 4 . 6. An impurity concentration of 3 × 10 ¹⁷ cm ^{-3 or} less.
6. The method as claimed in claim 1, wherein the lower part is a lower part.
14. The semiconductor laser device according to claim 1. 7. The impurity concentration is 2 × 10 ¹⁷ cm ^{-3 or} less.
7. The semiconductor laser device according to claim 6, wherein: 8. The impurity concentration is 5 × 10 ¹⁶ cm ^{-3 or} less.
Claim 1, 2, 3, 4, 5,
8. The semiconductor laser device according to 6 or 7 . 9. The method according to claim 1, wherein the impurity concentration is 7 × 10 ¹⁶ cm ^{−3 or} less.
9. The semiconductor laser device according to claim 8, wherein: 10. The impurity concentration is 1 × 10 ¹⁷ cm ^-3.
It is near, Claim 1, 2, 3, 4 or
6. The semiconductor laser device according to 5 . 11. The light confinement layer is doped with Se.
1, 2, 3, 4, 5, 6,
11. The semiconductor laser device according to 7, 8, 9 or 10 . 12. The light confinement layer is provided on the light confinement layer.
Current block of the first conductivity type with higher heat conduction efficiency than the first layer
Claims 1, 2, 3, 4, comprising a layer
The semiconductor laser device according to 5, 6, 7, 8, 9, 10, or 11 . 13. The light confinement layer is provided on the light confinement layer.
Current block of the first conductivity type having a higher impurity concentration than the first layer
Claims 1, 2, 3, 4, comprising a layer
13. The semiconductor laser device according to 5, 6, 7, 8, 9, 10, 11 or 12 . 14. The current blocking layer is made of GaAs.
14. The semiconductor laser device according to claim 12, wherein: 15. At least the active layer of the light confinement layer
The carrier concentration on the active layer side is about 5 × 10 ¹⁶ cm ⁻³ or more.
Claims 1, 2, 3, 4, 5, 6, 7,
The semiconductor laser device according to 8, 9, 10, 11, 12, 13 or 14 . 16. The light confinement layer is a low resistance layer.
Claims 1, 2, 3, 4, 5, 6, 7,
The semiconductor laser device according to 8, 9, 10, 11, 12, 13, 14 or 15 .