JP2009152296A - Method of manufacturing surface-emitting semiconductor laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of efficiently manufacturing a surface-emitting semiconductor laser having desired wavelength relation by fabricating the surface-emitting semiconductor laser accurately to a desired thickness with a small number of times of trial manufacture. <P>SOLUTION: The method of manufacturing the surface-emitting semiconductor laser includes the steps of: forming a lower mirror, an active layer, a first semiconductor layer having the same layer constitution with the upper mirror, a second semiconductor layer, and a third semiconductor layer on a first substrate; performing reflectivity inspection to measure the center wavelength of a reflection band of the first and third semiconductor layers and the resonance wavelength of a first optical resonator having the first to third semiconductor layers; calculating a lower and an upper mirror forming time to calculate a first and a second calculated value; finding the thickness of the active layer in the second calculated value and the thickness of the active layer in the desired resonance wavelength of a second optical resonator having a lower and an upper mirror and an active layer, from the relation between thicknesses of the active layer and resonance wavelengths of the second optical resonator; calculating an active layer forming time; forming a lower and an upper mirror and an active layer on a second substrate; and forming a first and a second electrode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a surface emitting semiconductor laser.

In the field of semiconductor lasers, surface emitting semiconductor lasers (hereinafter also referred to as “surface emitting lasers”) such as vertical cavity surface emitting lasers (VCSELs) have attracted a great deal of attention as inexpensive and high performance light sources. In general, the surface emitting laser has a structure in which the thickness of each layer of the distributed Bragg reflection (DBR) mirror is λ _D / 4n and the thickness of the active layer is mλ _D / 2n (for example, the following non-layered laser). Patent Document 1). Where λ _D is the design resonance wavelength, n is the refractive index of each layer, and m is a positive integer.
"Surface emitting laser" Kenichi Iga, Fumio Koyama, Ohmsha, (1990/09)

However, when a surface emitting laser is actually produced using a film forming apparatus such as a MOCVD (Metal Organic Chemical Vapor Deposition) apparatus or an MBE (Molecular Beam Epitaxy) apparatus, the desired thickness may not always be obtained accurately. The actual resonance wavelength is affected by the periodicity of the DBR mirror (electromagnetic field profile due to multiple reflection at the DBR mirror portion), and is not determined only by the thickness of the active layer. That is, for example, if the thickness of the DBR mirror becomes thicker than λ _D / 4n at the time of film formation, even if the thickness of the active layer is exactly mλ _D / 2n, the actual resonance wavelength is The wavelength becomes longer than the design resonance wavelength (λ _D ).

  One of the objects of the present invention is a method for efficiently producing a surface emitting semiconductor laser having a desired wavelength relationship by accurately producing a surface emitting semiconductor laser with a desired thickness with a small number of trial manufactures. It is to provide.

A method for manufacturing a surface emitting semiconductor laser according to the present invention includes:
Depositing a first semiconductor layer having the same layer configuration as the lower mirror above the first substrate in a deposition time (t ₁₀ );
Depositing a second semiconductor layer having the same layer configuration as the active layer above the first semiconductor layer in a deposition time (t ₂₀ );
Depositing a third semiconductor layer having the same layer configuration as the upper mirror over the second semiconductor layer in a deposition time (t ₃₀ );
A reflectance test is performed on the semiconductor multilayer film including the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer, and a central wavelength (in a reflection band of the first semiconductor layer and the third semiconductor layer) λ _S0 ), and measuring a resonance wavelength (λ _D0 ) of a first optical resonator having the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer;
The center wavelength of the desired reflection band of the lower mirror and the upper mirror is λ _S , and the lower mirror film formation time (t ₁₁ ) and the upper mirror film formation time (t ₃₁ ) are expressed by the following equations (1) and (2) The first calculation value (t ₂₁ ) and the second calculation value (λ ₁ ) for calculating the active layer deposition time (t ₂₂ ) are calculated from the following formulas (3) and (4). When,
A thickness (x) of a part or all of the active layer when the lower mirror and the upper mirror are fixed to a desired thickness, and a second mirror having the lower mirror, the active layer, and the upper mirror. From the relationship with the resonance wavelength (λ) of the optical resonator, the thickness (x _λ1 ) of a part or all of the active layer at the second calculated value (λ ₁ ) and the desired value of the second optical resonator Λ _D is a resonance wavelength of λ _D , and the thickness (x _λD ) of a part or all of the active layer at λ _D is obtained;
Calculating the active layer deposition time (t ₂₂ ) from the following equation (5);
Depositing a lower mirror on the second substrate at the lower mirror deposition time (t ₁₁ );
Depositing an active layer above the lower mirror with the active layer deposition time (t ₂₂ );
Depositing an upper mirror above the active layer at the upper mirror deposition time (t ₃₁ );
Forming a first electrode electrically connected to the lower mirror and a second electrode electrically connected to the upper mirror.

t ₁₁ = t ₁₀ × (λ _S / λ _S0 ) (1)
t ₃₁ = t ₃₀ × (λ _S / λ _S0 ) (2)
t ₂₁ = t ₂₀ × (λ _S / λ _S0 ) (3)
λ ₁ = λ _D0 × (λ _S / λ _S0 ) (4)
t ₂₂ = t ₂₁ × (x _λD / x _λ1 ) (5)
According to the method of manufacturing the surface emitting semiconductor laser according to the present invention, the lower mirror film formation time (t ₁₁ ), the active layer film formation time (t ₂₂ ), and the upper mirror film formation time (t ₃₁ ). An accurate value can be calculated in advance. That is, the center wavelength λ _S of the desired reflection band of the lower mirror and the upper mirror and the desired resonance wavelength λ _D of the second optical resonator need to be individually matched by repeating the trial production twice. Absent. Therefore, it is possible to accurately produce a desired thickness with a single correction without performing an extra trial production, which leads to resource saving and manufacturing cost reduction.

  In the description of the present invention, the word “upper” is used, for example, “an upper part of a specific member (hereinafter referred to as“ A member ”) and another specific member (hereinafter referred to as“ B member ”). "Membrane". In the description according to the present invention, in this case, the B member is directly formed on the A member, and the B member is formed on the A member via another material. The word “above” is used to include

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
From the relationship between the thickness (x) of part or all of the active layer and the resonance wavelength (λ) of the second optical resonator having the lower mirror, the active layer, and the upper mirror, Calculating a change rate (f) of a resonance wavelength (λ) of the second optical resonator with respect to a part or all of the thickness (x),
The rate of change (f) is represented by the following formula (6):
The active layer deposition time (t ₂₂ ) can be calculated from the following equation (5-2) obtained by modifying the above equation (5).

f = (λ _D −λ ₁ ) / (x _λD −x _λ1 ) (6)

本発明に係る面発光型半導体レーザの製造方法において、
前記活性層の一部または全部の厚さ（ｘ）と、前記下部ミラー、前記活性層、および前記上部ミラーを有する第２光共振器の共振波長（λ）との関係から、前記活性層の一部または全部の厚さ（ｘ）に対する前記第２光共振器の共振波長（λ）の変化率（ｆ）を求める計算工程を有し、
前記変化率（ｆ）は、前記活性層の一部または全部の厚さ（ｘ）と、前記下部ミラー、前記活性層、および前記上部ミラーを有する第２光共振器の共振波長（λ）との関係における、λ_Ｄとλ_１の中間波長（λ_Ｄ＋λ_１）／２における微分値の下記式（７）で表され、
前記活性層成膜時間（ｔ_２２）は、上記式（５）を変形した下記式（５−２）から算出されることができる。

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
From the relationship between the thickness (x) of part or all of the active layer and the resonance wavelength (λ) of the second optical resonator having the lower mirror, the active layer, and the upper mirror, Calculating a change rate (f) of a resonance wavelength (λ) of the second optical resonator with respect to a part or all of the thickness (x),
The rate of change (f) is the thickness (x) of a part or all of the active layer, and the resonance wavelength (λ) of the second optical resonator having the lower mirror, the active layer, and the upper mirror. In the relationship, λ _D and λ ₁ are expressed by the following equation (7) of the differential value at the intermediate wavelength (λ _D + λ ₁ ) / 2,
The active layer deposition time (t ₂₂ ) can be calculated from the following equation (5-2) obtained by modifying the above equation (5).

本発明に係る面発光型半導体レーザの製造方法において、
前記下部ミラーおよび前記上部ミラーの所望の反射帯域の中心波長（λ_Ｓ）と、前記第２光共振器の所望の共振波長（λ_Ｄ）とは、異なる波長であることができる。

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
The center wavelength (λ _S ) of the desired reflection band of the lower mirror and the upper mirror may be different from the desired resonance wavelength (λ _D ) of the second optical resonator.

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
A center wavelength (λ _S ) of a desired reflection band of the lower mirror and the upper mirror and a desired resonance wavelength (λ _D ) of the second optical resonator may be the same wavelength.

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
The lower mirror and the upper mirror are formed of a multilayer mirror in which a plurality of unit multilayer films are stacked,
The unit multilayer film is formed to have a pair of a low refractive index layer and a high refractive index layer stacked in the vertical direction,
The unit multilayer film is formed to satisfy the following formula (I):
The active layer may be formed to satisfy the following formula (II).

_{x D <λ D / 2n D} ... (I)
_{x A> mλ D / 2n A} ... (II)
However,
m is a positive integer;
x _D is the thickness of the unit multilayer film,
n _D is an average refractive index of the unit multilayer film,
x _A is the thickness of the active layer;
n _A is the average refractive index of the active layer.

  In the present invention, when “a pair of low refractive index layer and high refractive index layer laminated in the vertical direction” is referred to, another layer is laminated between the low refractive index layer and the high refractive index layer. Such cases are included.

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
As a part of the active layer in the calculation step, a confinement layer included in the active layer can be used.

  In the present invention, the “confinement layer” refers to a structure in which electrons are efficiently injected and confined in the quantum well.

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
The rate of change (f) may be greater than 0.46 and less than 0.92.

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
The calculation process may be performed using a time domain difference method.

In the method for manufacturing a surface emitting semiconductor laser according to the present invention,
The calculation process may be performed using a one-dimensional time domain difference method.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

  1. First, the surface emitting laser 100 according to the present embodiment will be described.

  FIG. 1 is a cross-sectional view schematically showing a surface emitting laser 100, and FIG. 2 is a schematic view showing an enlarged region V in FIG.

  As shown in FIG. 1, the surface emitting laser 100 includes a substrate 101, a lower mirror 10, an active layer 103, an upper mirror 20, an insulating layer 110, a first electrode 107, and a second electrode 109. Can be included.

  As the substrate 101, for example, a first conductivity type (for example, n-type) GaAs substrate or the like can be used.

On the substrate 101, for example, a first conductivity type lower mirror 10 is formed. The lower mirror 10 is a multilayer mirror in which a plurality of unit multilayer films 10p are stacked. As shown in FIG. 2, the unit multilayer film 10p can be composed of, for example, a low refractive index layer 10L and a high refractive index layer 10H formed under the low refractive index layer 10L. That is, the lower mirror 10 can be, for example, a distributed Bragg reflection (DBR) mirror in which low refractive index layers 10L and high refractive index layers 10H are alternately stacked. The low refractive index layer 10L can be composed of, for example, an n-type Al _0.9 Ga _0.1 As layer (refractive index 3.049). The high refractive index layer 10H can be composed of, for example, an n-type Al _0.12 Ga _0.88 As layer (refractive index 3.544). The number of stacked units (number of pairs) of the unit multilayer film 10p can be, for example, 35.5 pairs to 43.5 pairs. The unit multilayer film 10p of the lower mirror 10 may be any unit as long as the lower mirror 10 is configured by repeating the layer configuration of the unit multilayer film 10p. For example, the unit multilayer film 10p can include a low refractive index layer 10L and a high refractive index layer 10H formed on the low refractive index layer 10L.

An active layer 103 is formed on the lower mirror 10. The active layer 103 has, for example, a GRIN-SCH (graded-index separate-confinement heterostructure) structure. Examples of the structure of the active layer 103 include a structure in which a multiple quantum well (MQW) structure 304 is sandwiched between confinement layers 302 and 306 that are graded index layers formed above and below the structure. Examples of the MQW structure 304 include a structure in which three quantum well structures each composed of a GaAs well layer 303 and an Al _0.3 Ga _0.7 As barrier layer 305 are stacked as shown in FIG. FIG. 3 is a diagram schematically showing the aluminum (Al) composition of the active layer 103 and the AlGaAs layer in the vicinity thereof. The Al composition of the AlGaAs layer is the Al composition relative to the group III source (Al and Ga). The Al composition is 0 to 1. That is, the AlGaAs layer includes a GaAs layer (when the Al composition is 0) and an AlAs layer (when the Al composition is 1).

  Further, as the lower confinement layer 302 formed under the MQW structure 304, for example, as shown in FIG. 3, the Al composition of the AlGaAs layer is continuously decreased upward from 0.9 to 0.3. Can be mentioned. As the upper confinement layer 306 formed on the MQW structure 304, for example, as shown in FIG. 3, the Al composition of the AlGaAs layer is continuously increased upward from 0.3 to 0.6. Is mentioned.

On the active layer 103, for example, a second conductivity type (for example, p-type) upper mirror 20 is formed. The upper mirror 20 is a multilayer film mirror in which a plurality of unit multilayer films 20p are stacked. As shown in FIG. 2, the unit multilayer film 20p can include, for example, a low refractive index layer 20L and a high refractive index layer 20H formed under the low refractive index layer 20L. That is, the upper mirror 20 can be, for example, a DBR mirror in which low refractive index layers 20L and high refractive index layers 20H are alternately stacked. The low refractive index layer 20L can be composed of, for example, a p-type Al _0.9 Ga _0.1 As layer (refractive index 3.049). The high refractive index layer 20H can be composed of, for example, a p-type Al _0.12 Ga _0.88 As layer (refractive index 3.544). The number of stacked unit multilayer films 20p (number of pairs) can be, for example, 19 to 31 pairs. The unit multilayer film 20p of the upper mirror 20 may be any unit as long as the upper mirror 20 is configured by repeating the layer configuration of the unit multilayer film 20p. For example, the unit multilayer film 20p can include a low refractive index layer 20L and a high refractive index layer 20H formed on the low refractive index layer 20L.

  In the present embodiment, for example, the following formula (I) can be satisfied for all of the plurality of unit multilayer films 10p and 20p described above. In the present embodiment, the active layer 103 can satisfy the following formula (II).

_{x D <λ D / 2n D} ... (I)
_{x A> mλ D / 2n A} ... (II)
However,
λ _D is the design resonance wavelength of the surface emitting laser 100,
m is a positive integer;
x _D, the unit multilayer film 10p, the thickness of 20p,
n _D is an average refractive index of the unit multilayer films 10p and 20p,
x _A is the thickness of the active layer 103;
n _A is the average refractive index of the active layer 103.

The lower limit of x _D, and the upper limit value of x _A is, lambda _D can be determined by whether or not to enter the reflection band of the multilayer mirror (lower mirror 10 and the upper mirror 20). For example, in a multilayer mirror made of Al _x Ga _1-x As (x = 0.12, 0.90) with λ _D = 850 nm, the lower limit value of x _D is, for example, 5% with respect to λ _D / 2n _D The value can be reduced to some extent. The upper limit of x _A is appropriately determined according to the design resonance wavelength lambda _D, may be 20% of large value with respect to e.g. mλ _{D /} 2n _A.

  Moreover, the above-mentioned formulas (I) and (II) can be rewritten into the following formula (A).

2n _D · x _D <λ <(2n _A · x _A ) / m (A)
Further, from the above formulas (I) and (II), the ratio (x _A / x _D ) between the thickness x _A of the active layer 103 and the thickness x _D of the unit multilayer films 10p and 20p is expressed by the following formula (B ) Can be satisfied.

_{x A / x D> mn D} / n A ... (B)
The design wavelength λ _D is, for example, 780 nm, 850 nm, 1300 nm, etc., but is not particularly limited. When m is 2, for example, a 1λ resonator is configured.

In the present embodiment, for example, as shown in FIG. 2, the thicknesses of the plurality of unit multilayer films 10p in the lower mirror 10 and the thicknesses of the plurality of unit multilayer films 20p in the upper mirror 20 are the same x Can be _D. In the present embodiment, for example, the average refractive index of each of the plurality of unit multilayer films 10p in the lower mirror 10 and the average refractive index of each of the plurality of unit multilayer films 20p in the upper mirror 20 are the same n _D. Can be.

  Further, for example, among the plurality of unit multilayer films 10p in the lower mirror 10, there are two or more types of unit multilayer films 10p, and they may have different values. Further, for example, the average refractive index may be different from each other for two or more types of unit multilayer films 10p having different thicknesses among the plurality of unit multilayer films 10p in the lower mirror 10. Similarly, for example, among the plurality of unit multilayer films 20p in the upper mirror 20, there are two or more types of unit multilayer films 20p, and the values of the thickness and the average refractive index are different from each other. You can also. The above-described formula (I) only needs to be satisfied for at least one of the plurality of types of unit multilayer films 10p and 20p in the lower mirror 10 and the upper mirror 20. For example, the following formula (III) can be satisfied for the unit multilayer films 10p and 20p that do not satisfy the above-described formula (I).

_{x D = λ D / 2n D} ... (III)
For example, as shown in FIG. 2, the unit multilayer film 10p of the lower mirror 10 includes a low refractive index layer 10L and a high refractive index layer 10H, and the unit multilayer film 20p of the upper mirror 20 has a low refractive index layer 20L and a high refractive index. In the case of the rate layer 20H, the above-described formula (I) can be rewritten into the following formula (IV).

_{x H + x L <λ D} / 4n L + λ D / 4n H ... (IV)
However,
x _H is the thickness of the low refractive index layer;
x _L is the thickness of the high refractive index layer;
n _L is the refractive index of the low refractive index layer;
n _H is the refractive index of the high refractive index layer.

  Further, the threshold value of the surface emitting laser 100 can be adjusted by appropriately adjusting the number of unit multilayer films 10p in the lower mirror 10 and the number of unit multilayer films 20p in the upper mirror 20 described above. .

  In the surface emitting laser 100 according to the present embodiment, the following formulas (V) and (V I) can be satisfied instead of the above formulas (I) and (II).

x _D ≧ λ / 2n _D (V)
x _A ≦ mλ / 2n _A (VI)
The lower mirror 10, the active layer 103, and the upper mirror 20 can constitute a vertical resonator. The composition and the number of layers constituting the lower mirror 10, the active layer 103, and the upper mirror 20 can be appropriately adjusted as necessary. The upper limit of x _D, and the lower limit value of x _A also, lambda _D can be determined by whether or not to enter the reflection band of the multilayer mirror (lower mirror 10 and the upper mirror 20). The p-type upper mirror 20, the active layer 103 not doped with impurities, and the n-type lower mirror 10 constitute a pin diode. A part of the upper mirror 20, the active layer 103, and the lower mirror 10 can constitute a columnar semiconductor deposited body (hereinafter referred to as “columnar portion”) 30. The planar shape of the columnar portion 30 is, for example, a circle.

  In addition, as shown in FIG. 1, for example, at least one of the layers constituting the upper mirror 20 or a part thereof can be used as the current confinement layer 105. The current confinement layer 105 is formed in a region close to the active layer 103, for example. As the current confinement layer 105, for example, an oxidized AlGaAs layer or a proton implanted layer can be used. The current confinement layer 105 is an insulating layer having an opening. The current confinement layer 105 can be formed in a ring shape.

  A first electrode 107 is formed on the back surface of the substrate 101 (the surface opposite to the lower mirror 10 side). The first electrode 107 is electrically connected to the lower mirror 10 through the substrate 101. For example, the first electrode 107 can be formed on the upper surface side of the lower mirror 10 (around the columnar portion).

  A second electrode 109 is formed on the upper mirror 20 and the insulating layer 110. The second electrode 109 is electrically connected to the upper mirror 20. The second electrode 109 has an opening on the columnar part 30. Due to the opening, a region where the second electrode 109 is not provided is formed on the upper surface of the upper mirror 20. This region is the laser light emission surface 108. The planar shape of the emission surface 108 is, for example, a circle.

  The insulating layer 110 is formed on the lower mirror 10. The insulating layer 110 is formed so as to surround the columnar portion 30. The insulating layer 110 can electrically separate the second electrode 109 and the lower mirror 10.

  2. Next, an example of a method for manufacturing the surface emitting laser 100 according to the present embodiment will be described with reference to the drawings.

  4, 5, 13, and 14 are cross-sectional views schematically showing a manufacturing process of the surface emitting laser 100 of the present embodiment shown in FIG. 1.

(1) First, as shown in FIG. 4, a first semiconductor layer 210 having the same layer configuration as that of the lower mirror 10 is formed on the first substrate 201 at a film formation time t ₁₀ . As the first substrate 201, a substrate made of the same material as the substrate (second substrate) 101 described above is used. As the first substrate 201, for example, an n-type GaAs substrate can be used. An example of the first semiconductor layer 210 is the same as that of the lower mirror 10 described above. The first semiconductor layer 210 is formed while the composition is modulated using, for example, the MOCVD method, the MBE method, or the like.

(2) Next, as shown in FIG. 4, forming the second semiconductor layer 203 having the same layer structure as the active layer 103 on the first semiconductor layer 210 by deposition time _{t 20.} For example, a layer having the same layer configuration as that of the MQW structure 304 is formed at the deposition time t _M0 , and a layer having the same layer configuration as the lower and upper confinement layers 302 and 306 is formed by the deposition time t _C0 (two layers (Total time). An example of the second semiconductor layer 203 is the same as that of the active layer 103 described above. The formation of the second semiconductor layer 203 is performed while the composition is modulated using, for example, the MOCVD method, the MBE method, or the like.

(3) Next, as shown in FIG. 4, a third semiconductor layer 220 having the same layer configuration as the upper mirror 20 is formed on the second semiconductor layer 203 at a film formation time t ₃₀ . An example of the third semiconductor layer 220 is the same as that of the upper mirror 20 described above. The third semiconductor layer 220 is formed while the composition is modulated using, for example, the MOCVD method, the MBE method, or the like. When the third semiconductor layer 220 is formed, at least one layer or a part of the mirror in the vicinity of the second semiconductor layer 203 is a layer having the same layer configuration as a layer to be a current confinement layer 105 described later. be able to.

  (4) Through the above steps, as shown in FIG. 4, the first semiconductor layer 210, the second semiconductor layer 203, and the third semiconductor layer having the same layer configuration as the lower mirror 10, the active layer 103, and the upper mirror 20, respectively. A first semiconductor multilayer film 250 in which the semiconductor layers 220 are sequentially stacked is formed.

  (5) Next, as shown in FIG. 5, with respect to a first semiconductor multilayer film (also referred to as a first optical resonator) 250 having a first semiconductor layer 210, a second semiconductor layer 203, and a third semiconductor layer 220. To perform reflectivity inspection. In the reflectance inspection, for example, as shown in FIG. 5, light 311 is vertically emitted from a light source 310 that emits white light through a diffraction grating (not shown) and a half mirror 314 from the surface side of the first semiconductor multilayer film 250. The irradiation and reflected light 313 is made incident on a light receiving element 312 such as a CCD (Charge Coupled Device) through a half mirror 314.

FIG. 6 is a diagram schematically showing an example of the reflectance profile P0 obtained in this step. In the present embodiment, for example, a region between wavelengths when the reflectance is half of the maximum value can be set as the reflection band of the DBR mirror. In this step, as shown in FIG. 6, the wavelength λ _S0 at the center of the reflection band W ₀ of the DBR mirrors constituting the first semiconductor layer 210 and the third semiconductor layer 220 can be measured. λ _S0 is, for example, 835.0 nm (first example). Further, λ _S0 is, for example, 830.0 nm (second example).

Further, in the reflectance profile P0 obtained in this step, a dip is observed as shown in FIG. The wavelength at the lowest point of this dip is the resonance wavelength λ _D0 of the first optical resonator 250 having the first to third semiconductor layers 210, 203, and 220. That is, in this step, the resonance wavelength λ _D0 of the first optical resonator 250 can be measured. λ _D0 is, for example, 846.0 nm (first example). Further, λ _D0 is, for example, 849.0 nm (second example).

(6) Next, the first calculation step is performed. In the first calculation step calculates a lower mirror deposition time t ₁₁ in the step of forming the lower mirror 10 to be described later from the following equation (1).

t ₁₁ = t ₁₀ × (λ _S / λ _S0 ) (1)
Incidentally, lambda _S is the desired center wavelength of the reflection band W _S of the lower mirror 10 and the upper mirror 20 (design value). λ _S is, for example, 829.36 nm in the first and second examples.

Similarly, to calculate the upper mirror forming time t ₃₁ in the step of forming the upper mirror 20 described below from the following equation (2).

t ₃₁ = t ₃₀ × (λ _S / λ _S0 ) (2)
Further, a first calculation value t ₂₁ and a second calculation value λ ₁ for calculating an active layer deposition time t ₂₂ in the film formation step of the active layer 103 described later are calculated from the following formulas (3) and (4). To do.

t ₂₁ = t ₂₀ × (λ _S / λ _S0 ) (3)
λ ₁ = λ _D0 × (λ _S / λ _S0 ) (4)
For example, in the first example, λ ₁ is calculated as 846.0 × (829.36 / 835.0) = 840.3 nm by the equation (4). In the second example, λ ₁ is calculated as 849.0 × (829.36 / 830.0) = 848.3 nm.

In the first calculation step, the thicknesses of the first to third semiconductor layers 210, 203, and 220 (corresponding to the lower mirror 10, the active layer 103, and the upper mirror 20) have the same ratio (s = λ _S / λ _S0). ) To make fluctuations. It utilizes the fact that the thickness of each layer and the deposition time, and the thickness of each layer, the resonance wavelength, and the reflection wavelength band are in a proportional relationship. FIG. 7 is a diagram showing a virtual reflectance profile P1 for explaining the calculation in this step. As shown in FIG. 7, the reflectance profile P0 described above is shifted to, for example, the direction of the arrow A1 to become the reflectance profile P1 by the calculation in this step. Central wavelength lambda _S1 of the reflection band W _S of the reflectivity profile P1 after calculation, as can be seen from the following formula (a), the center wavelength lambda _S of the desired reflection band W _S of the lower mirror 10 and the upper mirror 20 Be the same.

λ _S1 = λ _S0 × s = λ _S0 × (λ _S / λ _S0 ) = λ _S (a)
In this step, the calculation can also be performed so that the thickness of only a part of the second semiconductor layer 203 (corresponding to the active layer 103) (for example, corresponding to the confinement layers 302 and 306) varies. Even in this case, if the calculation is performed so that the total thickness of the second semiconductor layer 203 after this step is the same as that described above, the optical path length hardly changes because the layer corresponding to the MQW structure 304 is thin. . That is, for example, when a layer corresponding to the confinement layers 302 and 306 is used as a part of the second semiconductor layer 203, the following formula (b) may be satisfied.

(X _M + x _C ) × s = x _M + x _{C ′} (b)
However, x _M is the thickness of the layer corresponding to the MQW structure 304 after this step, by multiplying s, first calculation in a case of varying the entire thickness of the layer corresponding to the active layer 103 This is the thickness of the layer corresponding to the MQW structure 304 after the process. x _C is the thickness of the layer corresponding to the confinement layers 302 and 306 after this step, and is the first in the case where the total thickness of the layer corresponding to the active layer 103 is changed by multiplying by s. It becomes the thickness of the layer corresponding to the confinement layers 302 and 306 after the calculation step. xC _′ is the thickness of the layer corresponding to the confinement layers 302 and 306 after the first calculation step when only the thickness of the layer corresponding to the confinement layers 302 and 306 is changed.

Therefore, the first calculated value t ₂₁ when the entire thickness of the layer corresponding to the active layer 103 is varied is simply s × (t _C0 + t _M0 ), but corresponds to the confinement layers 302 and 306. The first calculated value t ₂₁ when the thickness of only the layer to be changed is expressed by the following formula (c) from the above formula (b).

_{t 21 = t C0 × {x} C × s + (s-1) × x M} / x C + t M0 ... (c)
(7) Next, the lower mirror 10 and the upper mirror 20 are fixed to a desired thickness, and a part or all of the thickness x of the active layer 103 and the lower mirror 10, the active layer 103, and the upper mirror 20 are The step of calculating the relationship with the resonance wavelength λ of the second optical resonator 150 is performed. This calculation step is performed using, for example, a time domain difference (FDTD) method.

  FIG. 8 shows an optical simulation of the surface emitting laser 100 of the present embodiment using a one-dimensional FDTD method. The thickness x of the confinement layers 302 and 306 that are part of the active layer 103 and the resonance wavelength λ It is the result of calculating the relationship. Similarly, FIG. 9 shows the result of calculating the relationship between the total thickness x of the active layer 103 and the resonance wavelength λ using the one-dimensional FDTD method. In this simulation, the surface emitting lasers under four conditions 1 to 4 were used. The structure of the sample to which numerical calculation is applied is as follows.

Substrate 101: n-type GaAs substrate (refractive index 3.62)
The unit multilayer film 10p of the lower mirror 10 comprises an n-type Al _0.9 Ga _0.1 As layer (refractive index 3.049) and an n-type Al _0.12 Ga _0.88 As layer (refractive index 3.544). Two-layer structure Average refractive index n _D of unit multilayer film 10p of lower mirror 10: 2n _H n _L / (n _H + n _L ) = 3.278
Active layer 103: MQW structure 304 in which three quantum well structures composed of a GaAs layer (refractive index 3.6201) and an Al _0.2 Ga _0.8 As layer (refractive index 3.4297) are stacked are made of AlGaAs. GRIN-SCH structure sandwiched between the confinement layers (graded index layers) 302, 306 Average refractive index n _A of the active layer 103: 3.3838
The unit multilayer film 20p of the upper mirror 20 is composed of a p-type Al _0.9 Ga _0.1 As layer (refractive index 3.049) and a p-type Al _0.12 Ga _0.88 As layer (refractive index 3.544). Two-layer structure Average refractive index n _D of unit multilayer film 20p of upper mirror 20: 2n _H n _L / (n _H + n _L ) = 3.278
External space 40 of surface emitting laser 100: air (refractive index 1.00)
Refractive index of the Al _0.98 Ga _0.02 As layer that will later become the current confinement layer 105: 2.998
The thickness of the Al _0.98 Ga _0.02 As layer that will later become the current confinement layer: 12 nm
Resonance wavelength (design value) λ _D : 850 nm
The ratio x _A / x _D between the thickness x _A of the active layer 103 and the thickness x _D of the unit multilayer films 10p and 20p is equal to 2n _D / n _A at the resonance wavelength as designed. X _D = λ / 4n _H + λ / 4n _L = λ / 2n _D (= 129.66 nm) and x _A = mλ / 2n _A (= 253.77 nm). The x _A / x _D of the sample under the other conditions is 1.05 times 2n _D / n _A (= r ₀ = 1.96) under the condition 2 at the resonance wavelength as designed, and under the condition 3 1.10 times, and under condition 4, 1.15 times.

In each sample (conditions 1 to 4), the total thickness x _{D of} the unit multilayer films 10p and 20p that realize the resonance wavelength as designed, and the breakdown of the x _D (that is, the thickness of the high refractive index layers 10H and 20H) Thickness x _DH and the thickness x _{DL of the} low refractive index layers 10L and 20L), the thickness x _A of the active layer 103, the thickness x _CP of the upper confinement layer 306, the thickness x _CN of the lower confinement layer 302, and , X _A to x _D ratio x _A / x _D is shown in Table 1. Although it is an effective digit exceeding the lattice period of AlGaAs, it is a value used for calculation to the last, and there is no particular problem if a value according to reality is used. Further, the thickness of the upper confinement layer 306 and the thickness of the lower confinement layer 302 are designed to have the same optical path length. Table 2 shows the center wavelength λ _S of the reflection band, the number of pairs of the lower mirror 10, and the number of pairs of the upper mirror 20 in each sample (conditions 1 to 4). The thickness _{x D} and _{x A} in a sample condition 2-4 satisfies the above-mentioned formula (I) and (II).

_{x D <λ D / 2n D} ... (I)
_{x A> mλ D / 2n A} ... (II)
However, in this numerical calculation example, m = 2.

次に、表１の設計値から膜厚がずれた場合を想定して、活性層１０３全体の膜厚を変化させながら共振波長の計算を行い、活性層１０３の総厚さｘと共振波長λとの関係（図８）を得る。図８から、上述した第２計算値λ_１における活性層１０３の総厚さｘ_λ１、及び、第２光共振器１５０の所望の共振波長λ_Ｄにおける活性層１０３の総厚さｘ_λＤを求めることができる。図８に示す関係から、第１の例（条件４に相当）では、ｘ_λ１は、例えば２６４．８３ｎｍであり、ｘ_λＤは、例えば２８２．７０ｎｍであることが分かる。なお、図８における条件１〜４の近似曲線は、下記式でそれぞれ表される。

Next, assuming a case where the film thickness deviates from the design value in Table 1, the resonance wavelength is calculated while changing the film thickness of the entire active layer 103, and the total thickness x of the active layer 103 and the resonance wavelength λ are calculated. (FIG. 8). From FIG. 8, the total thickness x _λ1 of the active layer 103 at the second calculated value λ ₁ and the total thickness x _λD of the active layer 103 at the desired resonance wavelength λ _D of the second optical resonator 150 are obtained. be able to. From the relationship shown in FIG. 8, it can be seen that in the first example (corresponding to condition 4), x _λ1 is 264.83 nm, for example, and x _λD is 282.70 nm, for example. In addition, the approximate curve of the conditions 1-4 in FIG. 8 is each represented by a following formula.

Condition 1: y = −5.6826x ² + 3.7572x + 0.2653
Condition 2: y = −5.7723x ² + 3.7572x + 0.2612
Condition 3: y = −5.8206x ² + 3.7572x + 0.2590
Condition 4: y = −5.8692 × ² + 3.7572x + 0.2569
Further, from the relationship between the total thickness x of the active layer 103 and the resonance wavelength λ, the rate of change f of the resonance wavelength λ of the second optical resonator 150 with respect to the total thickness x of the active layer 103 can be obtained. The rate of change f can be obtained in part or all of the range where the resonance wavelength λ ranges from λ ₁ to λ _D, for example.

  The change rate f can be expressed by, for example, the following formula (6).

f = (λ _D −λ ₁ ) / (x _λD −x _λ1 ) (6)
Λ _D is a desired resonance wavelength of the second optical resonator 150, that is, a desired resonance wavelength (design value) of the surface emitting laser 100 of the present embodiment. In this simulation, λ _D = 850 nm. The desired resonance wavelength (λ _D ) of the second optical resonator 150 may be different from or the same as the center wavelength (λ _S ) of the desired reflection band of the lower mirror 10 and the upper mirror 20. .

  Moreover, the change rate f can also be represented by the following formula (7), for example.

また、図８を得るのと同様にコンファインメント層３０２，３０６の膜厚を変化させながら共振波長の計算を行う、または図８の活性層１０３全体の膜厚に上記関係式（ｂ）を適用することで、コンファインメント層３０２，３０６の厚さｘと共振波長λとの関係（図９）を導出することもできる。図９から、第２計算値λ_１におけるコンファインメント層３０２，３０６の厚さｘ_λ１、及び、第２光共振器１５０の所望の共振波長λ_Ｄにおけるコンファインメント層３０２，３０６の厚さｘ_λＤを求めることができる。図９に示す関係から、第１の例では、ｘ_λ１は、例えば１８２．７３ｎｍであり、ｘ_λＤは、例えば２００．６０ｎｍであることが分かる。また、コンファインメント層３０２，３０６の厚さｘと共振波長λとの関係から、コンファインメント層３０２，３０６の厚さｘに対する第２光共振器１５０の共振波長λの変化率ｆを求めることができる。変化率ｆは、例えば、上記式（６）、式（７）などで表されることができる。

In addition, the resonance wavelength is calculated while changing the film thickness of the confinement layers 302 and 306 as in the case of obtaining FIG. 8, or the relational expression (b) is applied to the film thickness of the entire active layer 103 in FIG. By doing so, the relationship (FIG. 9) between the thickness x of the confinement layers 302 and 306 and the resonance wavelength λ can also be derived. From FIG. 9, the thickness x _λ1 of the confinement layers 302 and 306 at the second calculated value λ ₁ and the thickness x _{λD of the} confinement layers 302 and 306 at the desired resonance wavelength λ _D of the second optical resonator 150 are obtained. Can be requested. From the relationship shown in FIG. 9, in the first example, it can be seen that x _λ1 is 182.73 nm, for example, and x _λD is 200.60 nm, for example. Further, the change rate f of the resonance wavelength λ of the second optical resonator 150 with respect to the thickness x of the confinement layers 302 and 306 can be obtained from the relationship between the thickness x of the confinement layers 302 and 306 and the resonance wavelength λ. it can. The change rate f can be expressed by, for example, the above formula (6), formula (7), and the like.

Note that FIG. 10 and FIG. 11 is the result of simulation performed by changing the lambda _D to 780 nm, respectively correspond to FIGS. 8 and 9.

(8) Next, to calculate the active layer deposition time _{t 22} in the step of forming the active layer 103 to be described later from the following formula (5) or (5-2) (second calculation step).

t ₂₂ = t ₂₁ × (x _λD / x _λ1 ) (5)

なお、上記式（５）において、ｘ_λＤの代わりにｘ_Ｆを用いることができる。ｘ_Ｆは、本算出工程後の第２半導体層２０３（活性層１０３に対応）の一部または全部の最終的な厚さを表している。ｘ_Ｆを用いる場合、ｔ_２２及びｔ_２１において、ｔ_２０と膜厚及び時間を変更しない部分、例えばＭＱＷ部分についてはｔ_２０に含まれるｔ_Ｍ０などと同じ値を用い、膜厚及び時間を変更する部分、例えばコンファインメント層部分についてのみ式（５）を適用する。具体的には、コンファインメント層３０２，３０６部分のみを変更する場合は、上記関係式（ｃ）において、コンファインメント層に相当する部分ｔ_Ｃ０×｛ｘ_Ｃ×ｓ＋（ｓ−１）×ｘ_Ｍ｝／ｘ_Ｃのみをｔ_２１として扱って（ｘ_Ｆ／ｘ_λ１）倍し、変更しない部分ｔ_Ｍ０はそのままの時間を用い、
ｔ_２２＝ｔ_Ｃ０×｛ｘ_Ｃ×ｓ＋（ｓ−１）×ｘ_Ｍ｝／ｘ_Ｃ×（ｘ_Ｆ／ｘ_λ１）＋ｔ_Ｍ０
とする。活性層１０３全体の膜厚を変更する場合は、
ｔ_２２＝ｓ×（ｔ_Ｃ０＋ｔ_Ｍ０）×（ｘ_Ｆ／ｘ_λ１）
である。

In the above formula (5), it can be used _{x F} instead of x _.lambda.D. x _F represents the final thickness of some or all of the second semiconductor layer 203 after the calculation step (corresponding to the active layer 103). When using a x _F, at _{t 22} and _{t 21,} using the same value as such _{t M0} contained in _{t 20} is the portion that does not change the _{t 20} and the film thickness and the time, for example MQW portion, changing the film thickness and the time Formula (5) is applied only to the part to be performed, for example, the confinement layer part. Specifically, when only the portions of the confinement layers 302 and 306 are changed, a portion t _C0 × {x _C × s + (s−1) × x _M corresponding to the confinement layer in the relational expression (c). } / X _C is treated as t ₂₁ and multiplied by (x _F / x _λ1 ), and the unmodified portion t _M0 uses the same time,
t ₂₂ = t _C0 × {x _C × s + (s−1) × x _M } / x _C × (x _F / x _λ1 ) + t _M0
And When changing the film thickness of the entire active layer 103,
t ₂₂ = s × (t _C0 + t _M0 ) × (x _F / x _λ1 )
It is.

For example, when λ ₁ and λ _D are close to each other as in the second example (in the second example, λ ₁ = 848.3 nm, λ _D = 850.0 nm), the rate of change f As the above, one represented by the above formula (7) can be used. In the case of the second example, the change rate f is a differential value at 849.15 nm, which is an average value of λ ₁ and λ _D , as represented by the above formula (7). Tables 3 and 4 show specific values of the change rate f in this case.

なお、表３は、上述した第１算出工程において、第１計算値ｔ_２１を第２半導体層２０３（活性層１０３に対応）の全部の厚さが変動するようにして求めた場合を示している。また、表４は、上述した第１算出工程において、第１計算値ｔ_２１を第２半導体層２０３（活性層１０３に対応）の一部（コンファインメント層３０２，３０６に対応）のみの厚さが変動するようにして求めた場合を示している。また、表３及び表４には、それぞれの場合におけるλ_Ｓ、ｘ_λ１、及びｘ_Ｆの値も併せて示してある。表３及び表４に示すように、活性層１０３またはコンファインメント層３０２，３０６の厚さｘに対する、波長λの変化率ｆは、０．４６より大きく、０．９２より小さな値となっている。即ち、面発光レーザ１００が、上述した下記式（Ｉ）及び（II）を満たすような構造である場合、例えば条件２〜４の場合は、条件１と比較して変化率ｆの値が小さい。従って、波長ずれ量が同程度の場合、より大きな補正が必要となることが分かる。

Incidentally, Table 3, in the first calculating step described above, shows a case in which all of the thickness of the first calculated value t ₂₁ second semiconductor layer 203 (corresponding to the active layer 103) is determined so as to vary Yes. Further, Table 4, in the first calculating step described above, the first calculated value _{t 21} part of the second semiconductor layer 203 (corresponding to the active layer 103) (corresponding to the confinement layer 302 and 306) only the thickness It shows the case where it is determined so that fluctuates. Tables 3 and 4 also show the values of λ _S , x _λ1 , and x _F in each case. As shown in Tables 3 and 4, the change rate f of the wavelength λ with respect to the thickness x of the active layer 103 or the confinement layers 302 and 306 is larger than 0.46 and smaller than 0.92. . That is, when the surface emitting laser 100 has a structure that satisfies the following formulas (I) and (II) described above, for example, in the case of the conditions 2 to 4, the value of the change rate f is smaller than that of the condition 1. . Therefore, it can be seen that when the amount of wavelength shift is the same, a larger correction is required.

x _D <λ / 2n _D (I)
x _A > mλ / 2n _A (II)
Specifically, as shown in Tables 3 and 4, the rate of change f when λ _S is 856.6 nm (condition 1) is the same as the rate of change f when λ _S is 829.4 nm (condition 4). It has doubled. That is, in the case of condition 4, it is necessary to correct the film formation time approximately twice as much as that in condition 1.

FIG. 12 is a diagram showing a virtual reflectance profile P2 for explaining this process. As shown in FIG. 12, by this step, only the dip in the reflectance profile P1 described above is shifted to the dip of the reflectance profile P2, for example, in the direction of the arrow A2. The wavelength λ _{2 at} the lowest point of dip of the reflectance profile P 2 after this step is the desired resonance wavelength λ _D of the surface emitting laser 100.

(9) Next, as shown in FIG. 13, the lower mirror 10 is deposited on the second substrate 101 at the lower mirror deposition time t ₁₁ described above. The film formation of the lower mirror 10 can be performed in the same manner as the film formation of the first semiconductor layer 210 described above.

(10) Next, as shown in FIG. 13, the active layer 103 is formed on the lower mirror 10 at the above-described active layer formation time t ₂₂ . The film formation of the active layer 103 can be performed in the same manner as the film formation of the second semiconductor layer 203 described above.

(11) Next, as shown in FIG. 13, the upper mirror 20 is deposited on the active layer 103 at the above-described upper mirror deposition time t ₃₁ . The film formation of the upper mirror 20 can be performed in the same manner as the film formation of the third semiconductor layer 220 described above. When forming the upper mirror 20, at least one of the mirrors in the vicinity of the active layer 103 or a part of the mirror can be formed into a layer that is oxidized later to become the current confinement layer 105. As the layer that becomes the current confinement layer 105, for example, an AlGaAs layer having an Al composition of 0.95 or more can be used. When a part of one layer of the mirror near the active layer is a layer to be the current confinement layer 105, for example, an Al _0.6 Ga _0.4 As layer or the like is used as the remaining part of the one layer. it can.

  (12) Through the above steps, the second semiconductor multilayer film 150 in which the lower mirror 10, the active layer 103, and the semiconductor layers constituting the upper mirror 20 are sequentially stacked is formed as shown in FIG.

  (13) Next, as shown in FIG. 14, the second semiconductor multilayer film 150 can be patterned to form the lower mirror 10, the active layer 103, and the upper mirror 20 having desired shapes. Thereby, the columnar part 30 is formed. The patterning of the second semiconductor multilayer film 150 can be performed using, for example, a lithography technique and an etching technique.

  Next, the current confinement layer 105 is formed by oxidizing the layer to be the current confinement layer 105 from the side surface by putting the entire substrate 101 in a water vapor atmosphere at about 400 ° C., for example. When the current confinement layer 105 is formed by proton implantation, the second semiconductor multilayer film 150 may not be patterned.

  (14) Next, as shown in FIG. 1, an insulating layer 110 is formed on the lower mirror 10 so as to surround the columnar portion 30. First, an insulating layer made of polyimide resin or the like is formed on the entire surface by using, for example, a spin coating method. Next, the upper surface of the columnar portion 30 is exposed using, for example, chemical mechanical polishing (CMP). Next, the insulating layer is patterned using, for example, a lithography technique and an etching technique. In this manner, the insulating layer 110 having a desired shape can be formed.

  (15) Next, as shown in FIG. 1, a first electrode 107 electrically connected to the lower mirror 10 and a second electrode 109 electrically connected to the upper mirror 20 are formed. These electrodes can be formed in a desired shape by, for example, a combination of a vacuum deposition method and a lift-off method. In addition, the order which forms each electrode is not specifically limited.

  (16) Through the above steps, the surface emitting laser 100 of the present embodiment is obtained as shown in FIG.

  5). Next, a modification of the surface emitting laser according to this embodiment will be described. Note that differences from the surface-emitting laser 100 shown in FIG. 1 (hereinafter referred to as “example of surface-emitting laser 100”) will be described, and description of similar points will be omitted.

  (1) First, a first modification will be described.

  FIG. 15 is a cross-sectional view schematically showing a part of a surface emitting laser according to this modification. The unit multilayer film 10p of the lower mirror 10 includes, for example, a low refractive index layer 10L, a first graded index layer (hereinafter referred to as “first GI layer”) 12 formed below the low refractive index layer 10L, and a first GI. The high refractive index layer 10H formed under the layer 12 and the second graded index layer (hereinafter referred to as “second GI layer”) 14 formed under the high refractive index layer 10H. As the first GI layer 12, for example, a layer in which the Al composition of the AlGaAs layer is continuously increased downward from 0.12 to 0.9 can be used. Further, as the second GI layer 14, for example, a layer in which the Al composition of the AlGaAs layer is continuously decreased downward from 0.9 to 0.12 can be used. Similarly, the unit multilayer film 20p of the upper mirror 20 is formed, for example, under the low refractive index layer 20L, the first GI layer 22 formed under the low refractive index layer 20L, and the first GI layer 22. The high refractive index layer 20H and the second GI layer 24 formed under the high refractive index layer 20H.

  (2) Next, a second modification will be described.

  In this modification, although not shown, the substrate 101 in the example of the surface emitting laser 100 can be separated using, for example, an epitaxial lift-off (ELO) method. That is, the surface emitting laser 100 can have no substrate 101.

  (3) Note that the above-described modifications are merely examples, and the present invention is not limited to these. For example, it is possible to appropriately combine the modified examples.

6). According to the method for manufacturing the surface emitting laser 100 of this embodiment, as described above, accurate values of the lower mirror film formation time t ₁₁ , the active layer film formation time t ₂₂ , and the upper mirror film formation time t ₃₁ are set in advance. Can be calculated. That is, the center wavelength λ _S of the desired reflection band of the lower mirror and the upper mirror and the desired resonance wavelength λ _D of the second optical resonator need to be individually matched by repeating the trial production twice. Absent. Therefore, it is possible to accurately produce a desired thickness with a single correction without performing an extra trial production, which leads to resource saving and manufacturing cost reduction.

  In the method of manufacturing the surface emitting laser 100 according to the present embodiment, as described above, the thickness of the layer corresponding to a part of the active layer 103 (a part other than the MQW structure 304, for example, the confinement layers 302 and 306). It is possible to perform the calculation by changing only the length. Thereby, since the thickness of the layer corresponding to the MQW structure 304 does not vary, it is possible to prevent variations in gain and gain band.

  In addition, the surface emitting laser 100 according to the present embodiment can have a novel structure that satisfies the following formulas (I) and (II).

x _D <λ / 2n _D (I)
x _A > mλ / 2n _A (II)
The manufacturing method of the surface emitting laser 100 of this embodiment is suitable for the manufacturing method of the surface emitting laser which has a novel structure where such an empirical rule does not exist.

  When the surface emitting laser 100 of the present embodiment satisfies the above formulas (I) and (II), the thickness of the current confinement layer 105, the opening diameter, the inclination angle θ of the post (columnar portion 30), the outer diameter, etc. Regardless, the resonance energy increase rate of the higher-order mode can be reduced without significantly reducing the increase rate of the resonance energy of the lower-order mode component. As a result, it is possible to prevent the higher-order mode from lasing without reducing the output of the surface emitting laser 100. Furthermore, even if the output is increased, it is possible to prevent the higher-order mode from lasing. Therefore, according to this embodiment, the number of oscillation modes of the surface emitting laser can be reduced, and higher output can be achieved than when the oscillation mode is reduced simply by reducing the diameter of the current confinement layer. A surface emitting laser can be provided. The reason why the surface emitting laser 100 of the present embodiment exhibits the functions and effects by satisfying the above formulas (I) and (II) is as follows.

The wave vector magnitude | k | in the resonator is an effective refractive index n _eff times the wave vector magnitude k ₀ in vacuum. This can be expressed as follows.

但し、ｋ_ｚは、共振器内の波数ベクトルの垂直方向の成分であり、ｋ_//は、面方向の成分である。

Here, k _z is a component in the vertical direction of the wave vector in the resonator, and k _// is a component in the plane direction.

k _z and k _// satisfy the continuity of the electromagnetic field within the range satisfying the total reflection condition at the boundary between the clad region including the current confinement layer 105 and the core region not including the current confinement layer 105. To be determined. In the surface emitting laser, k _z and n _eff k ₀ are close to each other, so that k _// is a small value as can be seen from the above-described equation. Therefore, the solution of k _// that satisfies the above-described continuity of the electromagnetic field, that is, the number of transverse modes allowed in the equation is limited. In the surface emitting laser, only those satisfying the total reflection condition oscillate. In the present invention, by further increasing k _z , the solution of k _// is further limited than the total reflection condition. k _z can be increased by the unit multilayer film 10p of the lower mirror 10 and the upper mirror 20, the thickness _{x D} of 20p thin. Thus, by limiting the solution of k _//, the number of laser light oscillation modes can be reduced. Further, it is possible to prevent the short-wavelength side by increasing the thickness x _A of the active layer 103.

Therefore, to reduce the _{x D,} increasing the _{x A,} i.e., by increasing the thickness ratio _x A / _{x D} (in particular larger than _mn D / _{n A),} the current constricting layer 105 Regardless of the thickness, the number of oscillation modes of the surface emitting laser can be reduced, and laser oscillation can be performed at a desired design wavelength.

  7. The surface emitting laser and the manufacturing method thereof according to the present embodiment described above include, for example, an element having an exhaust heat structure, an element having a flip chip structure, an element having an ESD protection structure, and a monitor photodiode (MPD). It is applied to an optical module such as an OSA (Optical Sub-Assembly) using a CAN or a ceramic package, an optical transmission device incorporating them, an element having the same, an element having an inkjet microlens, an element having a dielectric mirror, and the like. it can.

  Although the embodiments of the present invention have been described in detail as described above, those skilled in the art can easily understand that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention.

1 is a cross-sectional view schematically showing a surface emitting laser according to an embodiment. FIG. 3 is a cross-sectional view schematically showing a part of the surface emitting laser according to the embodiment. The figure which shows roughly the Al composition of the AlGaAs layer in the active layer and its vicinity. Sectional drawing which shows roughly one manufacturing process of the surface emitting laser of this embodiment. Sectional drawing which shows roughly one manufacturing process of the surface emitting laser of this embodiment. The figure which shows schematically an example of the reflectance profile obtained at a reflectance test process. The figure which shows the virtual reflectance profile for demonstrating a 1st calculation process. The result of calculating the relationship between the thickness x of the confinement layer and the resonance wavelength λ. The result of calculating the relationship between the total thickness x of the active layer and the resonance wavelength λ. The result of calculating the relationship between the thickness x of the confinement layer and the resonance wavelength λ. The result of calculating the relationship between the total thickness x of the active layer and the resonance wavelength λ. The figure which shows the virtual reflectance profile for demonstrating a 2nd calculation process. Sectional drawing which shows roughly one manufacturing process of the surface emitting laser of this embodiment. Sectional drawing which shows roughly one manufacturing process of the surface emitting laser of this embodiment. Sectional drawing which shows a part of modification of the surface emitting laser of this embodiment roughly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lower mirror, 12 1st GI layer, 14 2nd GI layer, 22 1st GI layer, 24 2nd GI layer, 20 Upper mirror, 30 Columnar part, 100 Surface emitting laser, 101 2nd board | substrate, 103 Active layer, 105 Current confinement layer , 107 first electrode, 108 emitting surface, 109 second electrode, 110 insulating layer, 150 second optical resonator (second semiconductor multilayer film), 201 first substrate, 203 second semiconductor layer, 210 first semiconductor layer, 220 third semiconductor layer, 250 first optical resonator (first semiconductor multilayer film), 302 lower confinement layer, 303 well layer, 304 MQW structure, 305 barrier layer, 306 upper confinement layer, 310 light source, 311 light, 312 light receiving element, 313 light, 314 half mirror

Claims (10)

Depositing a first semiconductor layer having the same layer configuration as the lower mirror above the first substrate in a deposition time (t ₁₀ );
Depositing a second semiconductor layer having the same layer configuration as the active layer above the first semiconductor layer in a deposition time (t ₂₀ );
Depositing a third semiconductor layer having the same layer configuration as the upper mirror over the second semiconductor layer in a deposition time (t ₃₀ );
A reflectance test is performed on the semiconductor multilayer film including the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer, and a central wavelength (in a reflection band of the first semiconductor layer and the third semiconductor layer) λ _S0 ), and measuring a resonance wavelength (λ _D0 ) of a first optical resonator having the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer;
The center wavelength of the desired reflection band of the lower mirror and the upper mirror is λ _S , and the lower mirror film formation time (t ₁₁ ) and the upper mirror film formation time (t ₃₁ ) are expressed by the following equations (1) and (2) The first calculation value (t ₂₁ ) and the second calculation value (λ ₁ ) for calculating the active layer deposition time (t ₂₂ ) are calculated from the following formulas (3) and (4). When,
A thickness (x) of a part or all of the active layer when the lower mirror and the upper mirror are fixed to a desired thickness, and a second mirror having the lower mirror, the active layer, and the upper mirror. From the relationship with the resonance wavelength (λ) of the optical resonator, the thickness (x _λ1 ) of a part or all of the active layer at the second calculated value (λ ₁ ) and the desired value of the second optical resonator Λ _D is a resonance wavelength of λ _D , and the thickness (x _λD ) of a part or all of the active layer at λ _D is obtained;
Calculating the active layer deposition time (t ₂₂ ) from the following equation (5);
Depositing a lower mirror on the second substrate at the lower mirror deposition time (t ₁₁ );
Depositing an active layer above the lower mirror with the active layer deposition time (t ₂₂ );
Depositing an upper mirror above the active layer at the upper mirror deposition time (t ₃₁ );
Forming a first electrode electrically connected to the lower mirror and a second electrode electrically connected to the upper mirror.
t ₁₁ = t ₁₀ × (λ _S / λ _S0 ) (1)
t ₃₁ = t ₃₀ × (λ _S / λ _S0 ) (2)
t ₂₁ = t ₂₀ × (λ _S / λ _S0 ) (3)
λ ₁ = λ _D0 × (λ _S / λ _S0 ) (4)
t ₂₂ = t ₂₁ × (x _λD / x _λ1 ) (5) In claim 1,
From the relationship between the thickness (x) of part or all of the active layer and the resonance wavelength (λ) of the second optical resonator having the lower mirror, the active layer, and the upper mirror, Calculating a change rate (f) of a resonance wavelength (λ) of the second optical resonator with respect to a part or all of the thickness (x),
The rate of change (f) is represented by the following formula (6):
The active layer deposition time (t ₂₂ ) is a method for manufacturing a surface emitting semiconductor laser, which is calculated from the following equation (5-2) obtained by modifying the above equation (5).
f = (λ _D −λ ₁ ) / (x _λD −x _λ1 ) (6)

In claim 1,
From the relationship between the thickness (x) of part or all of the active layer and the resonance wavelength (λ) of the second optical resonator having the lower mirror, the active layer, and the upper mirror, Calculating a change rate (f) of a resonance wavelength (λ) of the second optical resonator with respect to a part or all of the thickness (x),
The rate of change (f) is the thickness (x) of a part or all of the active layer, and the resonance wavelength (λ) of the second optical resonator having the lower mirror, the active layer, and the upper mirror. In the relationship, λ _D and λ ₁ are expressed by the following equation (7) of the differential value at the intermediate wavelength (λ _D + λ ₁ ) / 2,
The active layer deposition time (t ₂₂ ) is a method for manufacturing a surface emitting semiconductor laser, which is calculated from the following equation (5-2) obtained by modifying the above equation (5).

In any one of Claims 1 thru | or 3,
The center wavelength (λ _S ) of the desired reflection band of the lower mirror and the upper mirror is different from the desired resonance wavelength (λ _D ) of the second optical resonator. Production method. In any one of Claims 1 thru | or 3,
The center wavelength (λ _S ) of the desired reflection band of the lower mirror and the upper mirror and the desired resonance wavelength (λ _D ) of the second optical resonator are the same wavelength. Production method. In claim 4,
The lower mirror and the upper mirror are formed of a multilayer mirror in which a plurality of unit multilayer films are stacked,
The unit multilayer film is formed to have a pair of a low refractive index layer and a high refractive index layer stacked in the vertical direction,
The unit multilayer film is formed to satisfy the following formula (I):
The said active layer is a manufacturing method of the surface emitting semiconductor laser formed so that following formula (II) may be satisfy | filled.
_{x D <λ D / 2n D} ... (I)
_{x A> mλ D / 2n A} ... (II)
However,
m is a positive integer;
x _D is the thickness of the unit multilayer film,
n _D is an average refractive index of the unit multilayer film,
x _A is the thickness of the active layer;
n _A is the average refractive index of the active layer. In any one of Claims 1 thru | or 6.
A method for manufacturing a surface emitting semiconductor laser, wherein a confinement layer included in the active layer is used as a part of the active layer in the calculation step. In any one of Claims 2 to 4 and Claims 6 to 7,
The method of manufacturing a surface emitting semiconductor laser, wherein the rate of change (f) is greater than 0.46 and less than 0.92. In any one of Claims 1 thru | or 8.
The calculation step is a method for manufacturing a surface emitting semiconductor laser, which is performed using a time domain difference method. In any one of Claims 1 thru | or 9,
The calculation step is a method for manufacturing a surface emitting semiconductor laser, which is performed using a one-dimensional time domain difference method.

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