JP3846596B2 - Surface emitting semiconductor laser, optical module, and optical transmission device - Google Patents

Description

  The present invention relates to a surface emitting semiconductor laser, an optical module, and an optical transmission device.

  The surface emitting semiconductor laser has a characteristic that the light output varies depending on the environmental temperature. For this reason, an optical module using a surface emitting semiconductor laser has a light detection function for detecting a part of the laser light emitted from the surface emitting semiconductor laser and monitoring the light output value. There is a case. For example, by providing a light detection unit such as a photodiode in a surface emitting semiconductor laser, a part of laser light emitted from the surface emitting semiconductor laser can be monitored in the same element (for example, Patent Document 1). reference). However, in the case where a light detection unit is provided in a surface-emitting type semiconductor laser, the polarities of the layers that contribute to the generation of laser light (light-emitting element unit) and the layers constituting the light detection unit, and the electrodes of the light-emitting element unit and the light detection unit From the viewpoint of the structure, the structure of the surface emitting semiconductor laser is limited, and the degree of freedom of the structure may be reduced.

By the way, the surface emitting semiconductor laser can be driven at a high speed, and is applied to an electronic apparatus and an optical communication system by taking advantage of this feature. Therefore, high-speed driving is also required for a surface-emitting type semiconductor laser provided with a light detection unit.
Japanese Patent Laid-Open No. 10-135568

  An object of the present invention is to provide a surface-emitting type semiconductor laser including a photodetection section that has a degree of freedom in structure and can be driven at high speed.

  Another object of the present invention is to provide an optical module and an optical transmission device including the surface emitting semiconductor laser.

[Surface emitting semiconductor laser]
The surface emitting semiconductor laser of the present invention is
A light emitting element portion;
A light detecting portion provided on the light emitting element portion and having an emission surface,
The light emitting element unit includes a first mirror, an active layer provided above the first mirror, and a second mirror provided above the active layer,
The second mirror includes a first region and a second region,
The second region is in contact with the light detection unit;
The second region has a higher resistance than the first region.

  According to the surface-emitting type semiconductor laser of the present invention, since the second region has a higher resistance than the first region, the structure is flexible and high-speed driving is possible. Details will be described in the section of this embodiment.

  The surface-emitting type semiconductor laser can take the following aspects (1) to (11).

  (1) Furthermore, it may include a first electrode and a second electrode for driving the light emitting element portion, and the second electrode may be in contact with the first region. In this case, it further includes a third electrode and a fourth electrode for driving the light detection unit, and one of the first electrode and the second electrode, and any of the third electrode and the fourth electrode Either of them can be electrically connected at the electrode joint. In this case, the electrode joint portion can be provided in a region up to the electrode pad excluding the light emitting element portion and the light detection portion.

  (2) The film thickness of the second region may be 1 μm or more.

  (3) The first region and the second region contain impurities of a first conductivity type, and a concentration of the first conductivity type impurity in the second region is a concentration of the first conductivity type impurity in the first region. Can be lower.

(4) The impurity concentration of the second region may be less than 1 × 10 ¹⁶ [cm ⁻² ].

  (5) The second region may be semi-insulating by further including an impurity of a second conductivity type.

  (6) The second region may be made of an intrinsic semiconductor. Here, the “intrinsic semiconductor” means that most of the carriers involved in electric conduction are free electrons thermally excited from the valence band to the conductor or the same number of holes generated in the valence band. A semiconductor in which changes in carrier concentration due to the presence of lattice defects can be ignored.

  (7) The first region may include a current confinement layer.

  (8) The second region may include a spontaneous emission light reflecting layer.

  (9) The light detection unit may have a function of converting a part of the light generated in the light emitting element unit into a current.

  (10) The light detection unit includes a first contact layer, a light absorption layer provided above the first contact layer, and a second contact layer provided above the light absorption layer. Can do.

  (11) The light emitting element portion and the light detection portion may have a pnpn structure or an npnp structure as a whole.

[Optical module and optical transmission device]
The optical module of the present invention includes the surface emitting semiconductor laser and an optical waveguide. Moreover, the optical transmission apparatus of this invention contains the said optical module.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
1. Structure of Optical Device FIG. 1 is a cross-sectional view schematically showing a surface emitting semiconductor laser (hereinafter also referred to as “surface emitting laser”) 100 according to a first embodiment to which the present invention is applied. FIG. 2 is a plan view schematically showing the surface emitting laser 100 shown in FIG.

  The surface emitting laser 100 according to the present embodiment includes a light emitting element unit 140 and a light detection unit 120 as shown in FIG. In the surface emitting laser 100, laser light is generated in the light emitting element unit 140 and is emitted from the emission surface 108 provided in the light detection unit 120. The light detection unit 120 has a function of converting a part of the laser light generated in the light emitting element unit 140 into a current. Hereinafter, the light emitting element unit 140 and the light detection unit 120 will be described.

(Light emitting element)
The light emitting element part 140 is provided on a semiconductor substrate (in this embodiment, an n-type GaAs substrate) 101. The light emitting element portion 140 constitutes a vertical resonator (hereinafter referred to as “resonator”). The light emitting element portion 140 may include a columnar semiconductor deposited body (hereinafter referred to as “columnar portion”) 130.

The light emitting element unit 140 includes, for example, 40 pairs of distributed reflection type multilayer mirrors (hereinafter, referred to as “n-type Al _0.9 Ga _0.1 As layers and n-type Al _0.15 Ga _0.85 As layers”) , Called a “first mirror”) 102, an active layer 103 including a quantum well structure including a GaAs well layer and an Al _0.3 Ga _0.7 As barrier layer, and the well layer including three layers, and 25 pairs of A distributed reflection type multilayer mirror (hereinafter referred to as “second mirror”) 104 is sequentially laminated.

  A portion of the light emitting element portion 140 from the second mirror 104 to the middle of the first mirror 102 of the surface emitting laser 100 is etched into a circular shape when viewed from the direction perpendicular to the emission surface 108 to form a columnar portion 130. Yes. In this surface emitting laser 100, the planar shape of the columnar portion 130 is circular, but this shape can be any shape.

  The second mirror 104 includes a first region 104a and a second region 104b. As shown in FIG. 1, the second region 104b is provided on the first region 104a. In addition, the second region 104b is in contact with the light detection unit 120 (more specifically, the first contact layer 111 of the light detection unit 120). Further, in the surface emitting laser 100, as shown in FIGS. 1 and 2, when the semiconductor substrate 101 is cut along a plane parallel to the surface 101a, the cross section of the first region 104a is larger than the cross section of the second region 104b. large. Thereby, in the columnar section 130, a step is formed by the first region 104a and the second region 104b of the second mirror 104. That is, the second region 104b is provided on a part of the upper surface 104x of the first region 104a. A second electrode 109 (described later) is further provided on the upper surface 104x of the first region 104a.

  The second region 104b has a higher resistance than the first region 104a. For example, the second region 104b may be an intrinsic semiconductor. In the surface emitting laser 100 of the present embodiment, both the first region 104a and the second region 104b contain a first conductivity type (p-type) impurity, and the concentration of the p-type impurity in the second region 104b is the first region. The concentration is lower than the concentration of the p-type impurity 104a. In the present embodiment, the first conductivity type is p-type, but the first conductivity type can be n-type. This point can be similarly applied to other embodiments described later.

The impurity concentration of the second region 104b is preferably less than 1 × 10 ¹⁶ [cm ⁻² ]. Further, the film thickness of the second region 104b is desirably 1 μm or more.

More specifically, the first region 104a is configured by alternately stacking five pairs of p-type Al _0.9 Ga _0.1 As layers and p-type Al _0.15 Ga _0.85 As layers. The region 104b is configured by alternately stacking 20 pairs of p-type Al _0.9 Ga _0.1 As layers and p-type Al _0.15 Ga _0.85 As layers. In this case, the concentration of the p-type impurity in the first region 104a is, for example, 1 × 10 ¹⁸ [cm ⁻² ], and the concentration of the p-type impurity in the second region 104b is, for example, 1 × 10 ¹⁵ [cm ⁻² ]. .

  Note that the composition and the number of layers constituting each of the first mirror 102, the active layer 103, and the second mirror 104 are not limited thereto.

  At least the first region 104a of the second mirror 104 is made p-type by doping C, for example, and the first mirror 102 is made n-type by doping Si, for example. Therefore, a pin diode is formed by the first region 104 a of the p-type second mirror 104, the active layer 103 not doped with impurities, and the n-type first mirror 102.

  A current confinement layer 105 made of aluminum oxide is formed in a region near the active layer 103 in the first region 104a of the second mirror 104. The current confinement layer 105 is formed in a ring shape. In other words, the current confinement layer 105 has a shape in which the cross section when cut along a plane parallel to the surface 101a of the semiconductor substrate 101 shown in FIG. 1 is concentric.

  Further, the light emitting element portion 140 is provided with a first electrode 107 and a second electrode 109. The first electrode 107 and the second electrode 109 are used to drive the light emitting element portion 140 by applying a voltage. A second electrode 109 is provided on the upper surface 140 a of the light emitting element portion 140. Specifically, as shown in FIG. 2, the second electrode 109 has a ring-shaped planar shape. The first electrode 107 is provided so as to surround the columnar part 130, and the second electrode 109 is provided so as to surround the second region 104 b of the second mirror 104 and the light detection part 120. In other words, the columnar part 130 is provided inside the first electrode 107, and the second region 104 b of the second mirror 104 and the light detection part 12 are provided inside the second electrode 109. Note that the first electrode 107 can be formed in a predetermined planar shape.

  Further, although the case where the first electrode 107 is provided over the first mirror 102 has been described in this embodiment mode, the first electrode 107 may be provided on the back surface 101 b of the semiconductor substrate 101. The same applies to the surface emitting lasers of the embodiments described later.

  The first electrode 107 is made of, for example, a laminated film of an alloy of Au and Ge and Au. The second electrode 109 is made of a laminated film of Pt, Ti and Au, for example. A current is injected into the active layer 103 by the first electrode 107 and the second electrode 109. Note that the materials for forming the first electrode 107 and the second electrode 109 are not limited to those described above, and for example, an alloy of Au and Zn can be used.

(Light detector)
The light detection unit 120 is provided on the light emitting element unit 140 and has an emission surface 108. The light detection unit 120 includes a first contact layer 111, a light absorption layer 112, and a second contact layer 113. The first contact layer 111 is provided on the second mirror 104 of the light emitting element portion 140, the light absorption layer 112 is provided on the first contact layer 111, and the second contact layer 113 is provided on the light absorption layer 112. Yes. Further, in the light detection unit 120 of the present embodiment, the case where the planar shape of the first contact layer 111 is larger than the planar shape of the light absorption layer 112 and the second contact layer 113 is shown (FIGS. 1 and 1). 2). The third electrode 116 is provided on the first contact layer 111. That is, the first contact layer 111 is in contact with the third electrode 116.

  The first contact layer 111 can be made of, for example, an n-type GaAs layer, the light absorption layer 112 can be made of, for example, a GaAs layer into which no impurity is introduced, and the second contact layer 113 can be made of, for example, a p-type GaAs layer. Specifically, the first contact layer 111 is made n-type by doping Si, for example, and the second contact layer 113 is made p-type by doping C, for example. Therefore, the n-type first contact layer 111, the light absorption layer 112 that is not doped with impurities, and the p-type second contact layer 113 form a pin diode.

  The light detection unit 120 is provided with a third electrode 116 and a fourth electrode 110. The third electrode 116 and the fourth electrode 110 are used to drive the light detection unit 120. In the surface emitting laser 100 of the present embodiment, the third electrode 116 can be formed of the same material as the first electrode 107, and the fourth electrode 110 is formed of the same material as the second electrode 109. be able to.

  The fourth electrode 110 is provided on the upper surface of the light detection unit 120 (on the second contact layer 113). The fourth electrode 110 is provided with an opening 114, and the bottom surface of the opening 114 is the emission surface 108. Therefore, by appropriately setting the planar shape and size of the opening 114, the shape and size of the emission surface 108 can be appropriately set. In the present embodiment, as shown in FIG. 1, a case where the emission surface 108 is circular is shown.

(Overall configuration)
In the surface emitting laser 100 of the present embodiment, the n-type first mirror 102 and the p-type second mirror 104 of the light-emitting element unit 140 and the n-type first contact layer 111 and the p-type second contact of the light detection unit 120 are used. The layer 113 forms an npnp structure as a whole. That is, the surface emitting laser 100 has three pn junctions, and the semiconductor conductivity type changes three times in the structure. In each of the above layers, the pnpn structure can be configured as a whole by switching the p-type and the n-type. The above points are similarly applied to the surface emitting lasers of the embodiments described later.

  The polarity of the second region 104b of the second mirror 104 is not particularly limited. In the surface emitting laser 100 of the present embodiment, the case where the first conductivity type (p-type) impurity is introduced into the second region 104b is shown. However, the second region 104b further includes the second conductivity type (p-type). n-type) impurities may be further included. In this case, in the second region 104b, the second region 104b can be made semi-insulating by making the concentration of the first conductivity type impurity and the concentration of the second conductivity type impurity substantially equal. In the second region 104b, the second region 104b can be made to be the first conductivity type by making the concentration of the first conductivity type impurity higher than the concentration of the second conductivity type impurity, or By making the concentration of the second conductivity type impurity higher than the concentration of the first conductivity type impurity, the second region 104b can be made the second conductivity type.

  The light detection unit 120 has a function of monitoring the output of light generated by the light emitting element unit 140. Specifically, the light detection unit 120 converts light generated in the light emitting element unit 140 into a current. The output of light generated in the light emitting element unit 140 is detected by the value of this current.

  More specifically, in the light detection unit 120, a part of the light generated by the light emitting element unit 140 is absorbed by the light absorption layer 112, and this absorbed light causes photoexcitation in the light absorption layer 112, and electrons. And holes are generated. Electrons move to the third electrode 116 and holes move to the fourth electrode 110 by an electric field applied from the outside of the element. As a result, in the light detection unit 120, a current is generated in the direction from the first contact layer 111 to the second contact layer 113.

  The light output of the light emitting element unit 140 is mainly determined by the bias voltage applied to the light emitting element unit 140. In the surface emitting laser 100, the light output of the light emitting element unit 140 varies greatly depending on the ambient temperature of the light emitting element unit 140 and the lifetime of the light emitting element unit 140, as in a general surface emitting laser. Therefore, the light detection unit 120 monitors the light output of the light emitting element unit 140. That is, by adjusting the voltage value applied to the light emitting element unit 140 based on the value of the current generated in the light detection unit 120, the value of the current flowing in the light emitting element unit 140 is adjusted, whereby the light emitting element unit At 140, it is required to maintain a predetermined light output. The control for feeding back the light output of the light emitting element portion 140 to the voltage value applied to the light emitting element portion 140 can be performed using an external electronic circuit (drive circuit; not shown).

2. Operation of Surface Emitting Laser A general operation of the surface emitting laser 100 according to the present embodiment is described below. The following method for driving the surface emitting laser 100 is merely an example, and various modifications can be made without departing from the spirit of the present invention.

  First, when a forward voltage is applied to the pin diode between the first electrode 107 and the second electrode 109, recombination of electrons and holes occurs in the active layer 103 of the light emitting element portion 140, and the recombination is caused by the recombination. Luminescence occurs. Stimulated emission occurs when the generated light reciprocates between the second mirror 104 and the first mirror 102, and the light intensity is amplified. When the optical gain exceeds the optical loss, laser oscillation occurs and laser light is generated in the active layer 103. The laser light is emitted from the second mirror 104 of the light emitting element unit 140 and is incident on the first contact layer 111 of the light detection unit 120.

  Next, in the light detection unit 120, the light incident on the first contact layer 111 is then incident on the light absorption layer 112. As a result of a part of the incident light being absorbed by the light absorption layer 112, photoexcitation occurs in the light absorption layer 112, and electrons and holes are generated. Electrons move to the third electrode 116 and holes move to the fourth electrode 110 by an electric field applied from the outside of the element. As a result, a current (photocurrent) is generated in the direction from the first contact layer 111 to the second contact layer 113 in the light detection unit 120. By measuring the value of this current, the light output of the light emitting element portion 140 can be detected. Then, the light that has passed through the light detection unit 120 is emitted from the emission surface 108.

  According to the surface emitting laser 100 of the present embodiment, a part of the light output of the light emitting element unit 140 is monitored by the light detection unit 120 and fed back to the drive circuit, thereby correcting output fluctuation due to temperature or the like. Therefore, a stable light output can be obtained.

3. Next, an example of a method for manufacturing the surface-emitting laser 100 according to the first embodiment to which the present invention is applied will be described with reference to FIGS. 3 to 8 are cross-sectional views schematically showing one manufacturing process of the surface emitting laser 100 shown in FIG. 1, and correspond to the cross-sectional view shown in FIG.

(1) First, as shown in FIG. 3, a semiconductor multilayer film 150 is formed on the surface 101a of the semiconductor substrate 101 made of n-type GaAs by epitaxial growth while modulating the composition (see FIG. 3). Here, the semiconductor multilayer film 150 includes, for example, 40 pairs of first mirrors 102 in which n-type Al _0.9 Ga _0.1 As layers and n-type Al _0.15 Ga _0.85 As layers are alternately stacked, GaAs An active layer 103 including a quantum well structure including a well layer and an Al _0.3 Ga _0.7 As barrier layer, the well layer including three layers, a p-type Al _0.9 Ga _0.1 As layer, and a p-type Second mirror 104 composed of five pairs of first regions 104a and 20 pairs of second regions 104b in which Al _0.15 Ga _0.85 As layers are alternately stacked, first contact layer 111 composed of n-type GaAs, impurities Is formed of a light absorption layer 112 made of GaAs not doped with, and a second contact layer 113 made of p-type GaAs. By laminating these layers on the semiconductor substrate 101 in order, the semiconductor multilayer film 150 is formed (see FIG. 3).

  When the second mirror 104 is grown, at least one layer in the vicinity of the active layer 103 is formed as an AlAs layer or an AlGaAs layer having an Al composition of 0.95 or more. This layer is later oxidized to become the current confinement layer 105 (see FIG. 7). Further, when the second electrode 109 is formed in a later step, at least a portion of the first region 104a of the second mirror 104 in the vicinity of the portion in contact with the second electrode 109 is increased by increasing the carrier density. It is desirable to make an ohmic contact with the electrode 109 easy. Similarly, the vicinity of at least the portion of the first contact layer 111 in contact with the third electrode 116 and the vicinity of at least the portion of the second contact layer 113 in contact with the fourth electrode 110 are increased by increasing the carrier density, respectively. It is desirable to facilitate the ohmic contact between the third electrode 116 and the fourth electrode 110.

The temperature at which the epitaxial growth is performed is appropriately determined depending on the growth method and the raw material, the type of the semiconductor substrate 101, or the type, thickness, and carrier density of the semiconductor multilayer film 150 to be formed. Preferably there is. Further, the time required for performing the epitaxial growth is also appropriately determined similarly to the temperature. In addition, as a method of epitaxial growth, metal organic vapor phase epitaxy (MOVPE) method, MBE method (Molecular Beam), or the like.
(Epitaxial) method or LPE method (Liquid Phase Epitaxy) can be used.

  (2) Next, the second contact layer 113 and the light absorption layer 112 are patterned into a predetermined shape (see FIG. 4).

  First, after applying a photoresist (not shown) on the semiconductor multilayer film 150, the photoresist is patterned by photolithography to form a resist layer R1 having a predetermined pattern.

  Next, using the resist layer R1 as a mask, the second contact layer 113 and the light absorption layer 112 are etched by, eg, dry etching. As a result, the second contact layer 113 and the light absorption layer 112 having the same planar shape as the second contact layer 113 are formed. Thereafter, the resist layer R1 is removed.

  (3) Next, the first contact layer 111 and the second region 104b of the second mirror 104 are patterned into a predetermined shape (see FIG. 5). Specifically, first, after applying a photoresist (not shown) on the first contact layer 111 and the third contact layer 113, the photoresist is patterned by a photolithography method, whereby a resist having a predetermined pattern is obtained. Layer R2 is formed (see FIG. 5).

  Next, using the resist layer R2 as a mask, the first contact layer 111 and the second region 104b of the second mirror 104 are etched by, eg, dry etching. Through the above steps, the light detection unit 120 is formed as shown in FIG. The light detection unit 120 includes a second contact layer 113, a light absorption layer 112, and a first contact layer 111. Further, the planar shape of the first contact layer 111 can be formed larger than the planar shapes of the second contact layer 113 and the light absorption layer 112. Thereafter, the resist layer R2 is removed.

  In the above process, the case where the first contact layer 111 is patterned after the second contact layer 113 and the light absorption layer 112 are patterned has been described. However, after the first contact layer 111 is patterned, the second contact layer 113 is patterned. Alternatively, the light detection layer 120 may be formed by patterning the light absorption layer 112.

  (4) Next, the light emitting element part 140 including the columnar part 130 is formed by patterning (see FIG. 6). Specifically, first, after applying a photoresist (not shown) on the first region 104a of the second mirror 104 and the light detection unit 120, the photoresist is patterned by a photolithography method to obtain a predetermined predetermined value. A resist layer R3 having a pattern is formed (see FIG. 6).

  Next, using the resist layer R3 as a mask, the first region 104a of the second mirror 104, the active layer 103, and a part of the first mirror 102 are etched by, for example, a dry etching method. Thereby, as shown in FIG. 6, the columnar part 130 is formed. Through the above steps, a resonator (light emitting element portion 140) including the columnar portion 130 is formed on the semiconductor substrate 101. That is, a stacked body of the light detection unit 120 and the light emitting element unit 140 is formed. Thereafter, the resist layer R3 is removed.

  In the present embodiment, as described above, the case where the columnar portion 130 is formed after the light detection portion 120 is first formed has been described, but the light detection portion 120 may be formed after the columnar portion 130 is formed. Good.

  (5) Subsequently, the semiconductor substrate 101 on which the light emitting element part 140 and the light detection part 120 are formed by the above process is put in a water vapor atmosphere of about 400 ° C., for example, so that the second mirror 104 is formed by the above process. A layer having a high Al composition provided in the first region 104a is oxidized from the side surface to form a current confinement layer 105 (see FIG. 7).

  The oxidation rate depends on the furnace temperature, the supply amount of water vapor, the Al composition and the film thickness of the layer to be oxidized (the layer having a high Al composition). In a surface emitting laser having a current confinement layer formed by oxidation, current flows only in a portion where the current confinement layer is not formed (a portion not oxidized) during driving. Therefore, in the step of forming the current confinement layer by oxidation, the current density can be controlled by controlling the range of the current confinement layer 105 to be formed.

  In addition, it is desirable to adjust the diameter of the current confinement layer 105 so that most of the light emitted from the light emitting element portion 140 is incident on the first contact layer 111.

  (6) Next, the second electrode 109 is formed on the upper surface 104x of the first region 104a of the second mirror 104, and the fourth electrode 110 is formed on the upper surface of the light detection unit 120 (the upper surface 113a of the second contact layer 113). Formed (see FIG. 8).

  First, before forming the second electrode 109 and the fourth electrode 110, the upper surface 104x of the first region 104a and the upper surface 113a of the second contact layer 113 are cleaned using a plasma treatment method or the like as necessary. Thereby, an element having more stable characteristics can be formed.

  Next, a laminated film (not shown) of, for example, Pt, Ti, and Au is formed by, for example, a vacuum deposition method. Next, the second electrode 109 and the fourth electrode 110 are formed by removing the laminated film other than the predetermined position by a lift-off method. At this time, a portion where the laminated film is not formed is formed on the upper surface 113 a of the second contact layer 113. This portion becomes the opening 114, and the bottom surface of the opening 114 becomes the emission surface 108. In the above process, a dry etching method can be used instead of the lift-off method. Moreover, in the said process, although the 2nd electrode 109 and the 4th electrode 110 are patterned simultaneously, you may form the 2nd electrode 109 and the 4th electrode 110 separately.

  (7) Next, the first electrode 107 is formed on the first mirror 102 of the light emitting element section 140 by patterning a laminated film of, for example, an alloy of Au and Ge and Au by the same method, and light detection A third electrode 116 is formed on the first contact layer 111 of the portion 120 (see FIG. 1). Next, an annealing process is performed. The annealing temperature depends on the electrode material. In the case of the electrode material used in this embodiment, it is normally performed at around 400 ° C. Through the above steps, the first electrode 107 and the third electrode 116 are formed (see FIG. 1). Here, the first electrode 107 and the third electrode 116 may be formed by patterning at the same time, or the first electrode 107 and the third electrode 116 may be formed individually.

  Through the above steps, the surface emitting laser 100 including the light emitting element portion 140 and the light detecting portion 120 is obtained (see FIG. 1).

4). Operational Effects Hereinafter, operational effects of the surface emitting laser 100 according to the present embodiment will be described.

(1) Effect 1
First, before describing the operational effects of the surface emitting laser 100 according to the present embodiment, the structure of a known surface emitting laser 900 will be described.

(A) Known Surface Emitting Laser FIG. 23 is a cross-sectional view schematically showing a known surface emitting laser 900. A surface emitting laser 900 shown in FIG. 23 includes a light emitting element portion 940 and a light detecting portion 920. The light emitting element portion 940 is provided on the semiconductor substrate 901, and is configured by stacking an n-type first mirror 902, an active layer 903, and a p-type second mirror 904 in this order. The light detection portion 920 is provided on the light emitting element portion 940, and an n-type first contact layer 911, a light absorption layer 912 in which no impurity is introduced, and a p-type second contact layer 913 are sequentially stacked. Further, a first electrode 907 and a second electrode 909 for driving the light emitting element portion 940 are provided, and a third electrode 916 and a fourth electrode 910 for driving the light detection portion 920 are provided.

  An insulating layer 915 is provided between the light emitting element portion 940 and the light detection portion 120. The insulating layer 915 is made of a layer containing aluminum oxide, for example. It is formed by oxidizing a layer containing Al from the side. A surface emitting laser 900 including such an insulating layer 915 is disclosed in, for example, Japanese translations of PCT publication No. 2002-504754 and JP-A-2000-183444.

  In the surface emitting laser 900, a voltage is applied between the first electrode 907 and the second electrode 909 in order to drive the light emitting element portion 940. On the other hand, a predetermined voltage is also applied between the third electrode 916 and the fourth electrode 910 in order to drive the light detection unit 920.

  On the other hand, the insulating layer 915 is obtained by oxidizing a layer (not shown) containing Al. When the insulating layer 915 is formed by this method, the layer containing Al before oxidation is formed so as to be “sparse” so that oxygen easily enters the layer during oxidation and the oxidation proceeds easily. For this reason, since the insulating layer 915 obtained by oxidation is also “sparse”, the reliability is low and the mechanical strength is low. Therefore, in order to ensure reliability and mechanical strength, the insulating layer 915 must be formed with a small thickness. However, when the insulating layer 915 having a small thickness is provided between the light emitting element portion 940 and the light detection portion 920, a large parasitic capacitance is generated between the light emitting element portion 940 and the light detection portion 920. Generation of this parasitic capacitance hinders high-speed driving.

(B) Surface-emitting laser according to the present embodiment On the other hand, according to the surface-emitting laser 100 according to the present embodiment, the second mirror 104 includes the first region 104a and the second region 104b, and the second region 104b. Is in contact with the light detection unit 120, and the second region 104b has a higher resistance than the first region 104a. The second region 104b can be formed by normal epitaxial growth. Thereby, the film thickness of the second region 104b can be formed large. As a result, the parasitic capacitance generated between the light emitting element unit 140 and the light detection unit 120 can be reduced.

  Further, the second region 104b can be formed by epitaxial growth in the same manner as a normal mirror. Thereby, in the known surface emitting laser 900, the surface emitting laser 100 according to the present embodiment is superior in reliability and mechanical strength as compared with the insulating layer 915 obtained by oxidizing the layer containing Al. .

(2) Action effect 2
In addition, according to the surface emitting laser 100 of the present embodiment, one of the first electrode 107 and the second electrode 109 of the light emitting element unit 140 and the third electrode 116 and the fourth electrode 110 of the light detection unit 120 A three-terminal structure can be obtained by electrically connecting any one of the electrodes at the electrode joint.

  FIGS. 9A to 9D show a method of connecting the electrodes when the surface emitting laser 100 has a three-terminal structure. Moreover, the electrode connection structure for implement | achieving the connection method of the electrode shown to Fig.9 (a)-FIG.9 (d) is each typically shown as a top view in FIG.10 and FIG.14-16. Furthermore, the top view which cut | disconnected the top view shown in FIG. 10 along the AA line, the BB line, and CC line is shown in FIGS. 11-13, respectively.

  There are four methods for electrically connecting one of the first electrode 107 and the second electrode 109 of the light emitting element section 140 and one of the third electrode 116 and the fourth electrode 110 of the light detection section 120. 9A to 9D are shown as connection methods 1 to 4, respectively. 9A to 9D show electrode joint portions 160a to 160d, respectively.

(A) Connection method 1
In connection method 1, as shown in FIG. 9A and FIGS. 10 to 13, the second electrode 109 of the light emitting element portion 140 and the third electrode 116 of the light detection portion 120 are connected at the electrode joint portion 160 a. Electrically connected. More specifically, as shown in FIGS. 12 and 13, an electrode joint 160a is provided between the surface emitting laser 100 and an electrode pad (not shown), and the electrode joint 160a The two electrodes 109 and the third electrode 116 are electrically connected. That is, the second electrode 109 is provided on the third electrode 116 in the electrode connection portion 160a.

  The third electrode 116 is formed from the first contact layer 111 of the light detection unit 120 to the insulating layer 106b, and the second electrode 109 is insulated from the first region 104a of the second mirror 104 through the insulating layer 106a. It is formed over the layer 106 b and the second electrode 109. Note that the insulating layers 106a, 106b, and 106c may be formed in a lump or may be formed respectively. This also applies to connection methods 2 to 4 described later. Moreover, although illustration of sectional drawing is abbreviate | omitted about the connection methods 2-4, it has the same layer structure as the surface emitting laser 100 shown in FIGS. 10-13 about parts other than the electrode mentioned below.

(B) Connection method 2
In the connection method 2, as shown in FIG. 14, the second electrode 109 of the light emitting element part 140 and the fourth electrode 110 of the light detection part 120 are electrically connected by an electrode joint part 160b. The electrode joint 160b is provided between the surface emitting laser 100 and an electrode pad (not shown). In the electrode connection part 160 b, the second electrode 109 is provided on the fourth electrode 110.

  The fourth electrode 110 is formed from the second contact layer 113 to the insulating layer 106c, and the second electrode 109 extends from the first region 104a of the second mirror 104 to the fourth electrode 110 through the insulating layer 106c. Is formed.

(C) Connection method 3
In the connection method 3, as shown in FIG. 15, the first electrode 107 of the light emitting element unit 140 and the fourth electrode 110 of the light detection unit 120 are electrically connected by an electrode joint 160c. The electrode joint 160 c is provided from the surface emitting laser 100 to an electrode pad (not shown), and is provided in a region excluding the light emitting element portion 140 and the light detection portion 120. In the electrode connection part 160 c, the first electrode 107 is provided on the fourth electrode 110.

  The fourth electrode 110 is formed from the second contact layer 113 to the insulating layer 106c, and the first electrode 107 is formed from the first mirror 102 to the fourth electrode 110 through the insulating layer 106c.

(D) Connection method 4
In the connection method 4, as shown in FIG. 16, the first electrode 107 of the light emitting element unit 140 and the third electrode 116 of the light detection unit 120 are electrically connected by an electrode joint 160d. The electrode joint 160d is provided between the surface emitting laser 100 and an electrode pad (not shown). In the electrode connection portion 160 c, the first electrode 107 is provided on the third electrode 116.

  The third electrode 116 is formed from the first contact layer 111 to the insulating layer 106b, and the first electrode 107 is formed from the first mirror 102 to the third electrode 116 through the insulating layer 106b.

(E) Effect In connection method 1, as shown in FIG. 9A, the second electrode 109 of the light emitting element section 140 and the third electrode 116 of the light detection section 120 are electrically connected. . In this case, since no potential difference is generated between the second electrode 109 and the third electrode 116, no parasitic capacitance is generated between the light emitting element unit 140 and the light detection unit 120.

On the other hand, in the connection method 2, as shown in FIG. 9B, the second electrode 109 of the light emitting element section 140 and the fourth electrode 110 of the light detection section 120 are electrically connected. In this case, as a result of the potential difference between the second electrode 109 and the fourth electrode 110, a parasitic capacitance _Cp is generated. Here, when a “highly insulating layer” is formed between the light emitting element portion 140 and the light detection portion 120, the generated parasitic capacitance _Cp is large. That is, the smaller the film thickness of the “highly insulating layer”, the larger the parasitic capacitance _{Cp that} is generated.

Similarly, in the connection methods 3 and 4, when a potential difference is generated between the first electrode 107 and the fourth electrode 110 and between the first electrode 107 and the third electrode 116, a parasitic capacitance C _p is generated. To do.

For example, in the case of the known surface emitting laser 900 shown in FIG. 23, an insulating layer 915 is provided between the light emitting element portion 940 and the light detecting portion 120. As described above, the insulating layer 915 is formed by oxidizing a layer containing Al. As described above, the insulating layer 915 formed by oxidizing the layer containing Al has low mechanical strength. In particular, when the insulating layer 915 is formed thick, the mechanical strength of the surface emitting laser 100 is lowered. For this reason, the insulating layer 915 must be formed thin to some extent. However, when the thickness of the insulating layer 915 is small, the parasitic capacitance C _p generated between the light emitting element portion 940 and the light detection portion 120 increases.

On the other hand, according to the surface emitting laser 100 of the present embodiment, the second region 104b in the second mirror 104 of the light emitting element unit 140 has a higher resistance than the first region 104a, and the second region 104b. Is in contact with the light detection unit 120. Therefore, the second region 104b corresponds to a “highly insulating layer” provided between the light emitting element portion 140 and the light detection portion 120 in the connection methods 2 to 4 described above. However, since the second region 104b is a part of the second mirror 104, the second region 104b can be formed by normal epitaxial growth. For this reason, the second region 104b can be formed thick. That is, the film thickness of the second region 104b, which is a “highly insulating layer” provided between the light emitting element portion 140 and the light detection portion 120, can be formed large. Thus, the connection method 2-4 described above, it is possible to suppress the parasitic capacitance C _p which is generated, can be a surface-emitting laser 100 fast driven.

  As described above, according to the surface emitting laser 100 of the present embodiment, any of the connection methods 1 to 4 can be applied. Accordingly, since the connection method of each electrode can be changed without changing the laminated structure of the surface emitting laser 100, the surface emitting laser 100 having a three-terminal structure with a flexible structure and capable of high-speed driving. Obtainable. Further, the surface emitting laser 100 having a three-terminal structure in which the connection method between the electrodes is different can be obtained without changing the manufacturing process other than the electrode forming process.

(3) Effect 3
Furthermore, according to the surface emitting laser 100 of the present embodiment, the second mirror 104 is provided on the active layer 103, and the second region 104b of the second mirror 104 is provided on the first region 104a. In addition, the first electrode 107 and the second electrode 109 for driving the light emitting element portion 140 are included, and the second electrode 109 is in contact with the first region 104 a of the second mirror 104. That is, since the second electrode 109 is provided closer to the active layer 103, a voltage can be efficiently applied to the active layer 103.

  In addition, since the second region 104b is provided on the first region 104a and the second electrode 109 is provided on the first region 104a, no current flows in the second region 104b. That is, carriers do not move in the second region 104b, and carriers move only in the first region 104a. Therefore, since the inside of the surface emitting laser 100 can be moved via the heterojunction with fewer carriers, the surface emitting laser 100 having a lower resistance can be obtained.

  Further, in a general surface emitting laser, impurities are added in the mirror in order to reduce the resistance in the mirror. By the addition of this impurity, light absorption confusion may occur and the light emission efficiency may decrease. On the other hand, according to the surface emitting laser 100 of the present embodiment, the second region 104b of the second mirror 104 has a concentration of impurities having the same conductivity type as that of the first region 104a compared to the first region 104a. Low or same conductivity type impurities are not added. For this reason, the second region 104b has a higher resistance than the first region 104a. Thereby, the subject by addition of the impurity mentioned above can be solved.

[Second Embodiment]
1. Structure of Optical Element FIG. 17 is a cross-sectional view schematically showing a surface emitting laser 200 according to a second embodiment to which the present invention is applied. FIG. 18 is a plan view schematically showing the surface emitting laser 100 shown in FIG.

  The surface emitting laser 200 of the present embodiment has a configuration different from that of the surface emitting laser 100 of the first embodiment in that a reflective layer 305 is provided in the second region 104b of the second mirror 104. . Except for the points described above, the structure is the same as that of the surface emitting laser 100 of the first embodiment. Therefore, the same components as those of the surface emitting laser 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The reflective layer 305 has a function of reflecting spontaneously emitted light. The reflective layer 305 can be formed using, for example, the same material as the current confinement layer 105 (a layer containing aluminum oxide). In this case, the reflective layer 305 can be formed in the same process as the current confinement layer 105. That is, the reflective layer 305 can be formed by forming a layer (not shown) having a high Al composition in advance in the second region 104b of the second mirror 104 and oxidizing this layer from the side surface.

  An aluminum oxide (AlOx) layer is typically a dielectric layer that has a lower refractive index than the surrounding semiconductor layer. The refractive index of the aluminum oxide layer is approximately 1.6, and the refractive index of the semiconductor layer is usually 2.9 to 3.5.

  The film thickness of the reflective layer 305 can be set to n / 4 (n is a natural number) of the wavelength of laser light generated in the light emitting element portion 140. Thereby, the reflection of the mode of the laser beam can be increased.

2. Operation of Optical Element Since the basic operation of the surface emitting laser 200 of the present embodiment is the same as that of the surface emitting laser 100 of the first embodiment, detailed description thereof is omitted.

3. Effects The surface-emitting laser 200 according to the present embodiment has substantially the same functions and effects as the surface-emitting laser 100 according to the first embodiment.

  In addition, according to the surface emitting laser 200 according to the present embodiment, the light detection unit 120 has a function of detecting the light output of the light emitting element unit 140. Therefore, when light other than the laser beam generated in the light emitting element unit 140 enters the light detection unit 120, the output of the light generated in the light emitting element unit 140 may not be detected correctly. However, according to the surface emitting laser 200 of the present embodiment, the reflective layer 305 is provided in the second region 104b of the second mirror 104, thereby preventing spontaneous emission light from entering the light detection unit 120. can do. As a result, since only the laser beam generated in the light emitting element unit 140 can be incident on the light detection unit 120, the light detection unit 120 can more accurately detect the light output generated in the light emitting element unit 140. .

  Further, for example, when a reflection layer is provided in the light detection unit, the efficiency of the light detection unit may be reduced by this reflection layer. On the other hand, according to the surface emitting laser 200 according to the present embodiment, the reflective layer 305 is provided not in the light detection unit 120 but in the second region 104b of the second mirror 104. Therefore, the efficiency of the light detection unit 120 is not reduced.

  Further, no current flows through the second region 104b. Therefore, since the reflective layer 305 is provided in the second region 104b of the second mirror 104, the reflective layer 305 can be installed regardless of the current path. That is, the installation of the reflective layer 305 does not affect the current path. Therefore, the provision of the reflective layer 305 does not change the characteristics of the light emitting element portion 140.

  In addition, the reflective layer 305 can be formed by applying a commonly used mirror design, and therefore does not require a new manufacturing process.

[Third Embodiment]
1. FIG. 19 is a cross-sectional view schematically showing a surface emitting laser 300 according to a third embodiment to which the present invention is applied.

  The surface emitting laser 300 according to the present embodiment is different from the surface emitting laser 100 according to the first embodiment in that the light detection unit 220 and the light emitting element unit 240 are stacked on the semiconductor substrate 201 in this order. It has a configuration. In the surface-emitting laser 300 according to the present embodiment, a component similar to the component “1XX” of the surface-emitting laser 100 according to the first embodiment is denoted as “2XX”. That is, “2XX” represents the same component as “1XX” of the surface-emitting laser 100 of the first embodiment, and is basically made of the same material, so that detailed description thereof is omitted. Shall.

  The surface emitting laser 300 according to the present embodiment includes a light detection unit 220 provided on the semiconductor substrate 201 and a light emitting element unit 240 provided on the light detection unit 220. The surface emitting laser 300 emits light generated in the light emitting element unit 240 from the emission surface 208.

  The light detection unit 220 includes a second contact layer 213, a light absorption layer 212, and a first contact layer 211. The p-type second contact layer 213, the light absorption layer 212, and the n-type first contact layer 211 are laminated on the semiconductor substrate 201 made of p-type GaAs in this order. The second contact layer 213, the light absorption layer 212, and the first contact layer 211 are respectively formed from the same material as the second contact layer 113, the light absorption layer 112, and the first contact layer 111 of the first embodiment. be able to.

  The light emitting element unit 240 includes a second mirror 204, an active layer 203, and a first mirror 202. The second mirror 204 includes a first area 204a and a second area 204b. The second region 204b is in contact with the light detection unit 220 and has a higher resistance than the first region 204a. The p-type first region 204a and the second region 204b of the second mirror 204, the active layer 203, and the n-type first mirror 202 are stacked on the light detection unit 220 in this order. The first region 204a and the second region 204b of the second mirror 204, the active layer 203, and the first mirror 202 are the first region 104a and the second region 104b of the second mirror 104 of the first embodiment, and the active layer. 103 and the first mirror 102 can be made of the same material. The second mirror 204 is provided with a current confinement layer 205 as in the second mirror 104 of the first embodiment.

  The surface emitting laser 300 of the present embodiment also includes a first electrode 207, a second electrode 209, a third electrode 216, and a fourth electrode 210. The first electrode 207 and the second electrode 209 are used to drive the light emitting element unit 240. The third electrode 216 and the fourth electrode 210 are used for driving the light detection unit 220.

  The first electrode 207 is provided on the first mirror 202. The second electrode 209 is in contact with the first region 204 a of the second mirror 204. The third electrode 216 is provided on the first contact layer 211. The fourth electrode 210 is provided on the second contact layer 213. The second electrode 209, the third electrode 216, and the fourth electrode 210 may have a ring-like planar shape. In this case, the second electrode 209 is provided so as to surround the light emitting element portion 240, the third electrode 216 is provided so as to surround the light emitting element portion 240 and the first region 204a of the second mirror 204, and the fourth electrode 210 is The first contact layer 211 and the light absorption layer 212 are provided so as to surround them.

  Further, in the surface emitting laser 300 of the present embodiment, the surface in which a part of the light detection unit 220 is in contact with the semiconductor substrate 201 is the upper surface (surface 201a), and the side in contact with the light emitting element portion 240 is the lower surface (surface 201b). ), An emission surface 208 is provided on the upper surface (surface 201a) of the light detection unit 220. More specifically, in the surface emitting laser 300, an opening 214 that penetrates the semiconductor substrate 201 is provided in the semiconductor substrate 201, and the bottom surface of the opening 214 serves as an emission surface 208.

2. Operation of Optical Element In the surface-emitting laser 300 according to the present embodiment, the stacking order of the light-emitting element unit 240 and the light detection unit 220 on the semiconductor substrate 201 is reverse to that of the surface-emitting laser 100 according to the first embodiment. . However, the basic operation of the surface emitting laser 300 according to the present embodiment is the same as that of the surface emitting laser 100 according to the first embodiment, and thus detailed description thereof is omitted.

  That is, in the surface emitting laser 300 of the present embodiment, after laser light is generated in the light emitting element portion 240, the laser light passes through the light detection portion 220 and is emitted from the emission surface 208. Here, a part of the laser light generated in the light emitting element unit 240 is absorbed by the light absorbing layer 212 of the light detecting unit 220 and converted into a current, so that the light output generated in the light emitting element unit 240 is detected. Is done.

3. Operational Effect The surface emitting laser 300 according to the present embodiment has substantially the same operation and effect as the surface emitting laser 100 according to the first embodiment.

[Fourth Embodiment]
FIG. 20 is a diagram schematically showing an optical module 500 according to the fourth embodiment to which the present invention is applied. The optical module 500 includes the surface-emitting type semiconductor laser 100 (see FIG. 1) of the first embodiment, the semiconductor chip 20, and the optical fiber 30. In the optical module 500 of the present embodiment, the same effect is obtained even when the surface emitting semiconductor lasers of the other embodiments described above are used instead of the surface emitting semiconductor laser 100 of the first embodiment. And can produce effects. The same applies to fifth and sixth embodiments described later.

1. Structure of Optical Module The surface emitting semiconductor laser 100 absorbs light emitted from the end face 30 a of the optical fiber 30. The surface emitting semiconductor laser 100 is in a state in which the relative position to the end face 30a of the optical fiber 30 is fixed. Specifically, the emission surface 108 of the surface emitting semiconductor laser 100 faces the end surface 30 a of the optical fiber 30.

  The semiconductor chip 20 is installed to drive the surface emitting semiconductor laser 100. That is, the semiconductor chip 20 incorporates a circuit for driving the surface emitting semiconductor laser 100. The semiconductor chip 20 is formed with a plurality of electrodes (or pads) 22 electrically connected to an internal circuit. It is preferable that wiring patterns 24 and 64 electrically connected to at least one electrode 22 are formed on the surface on which the electrode 22 is formed.

  The semiconductor chip 20 and the surface emitting semiconductor laser 100 are electrically connected. For example, the wiring pattern 14 and the wiring pattern 24 formed on the semiconductor chip 20 are electrically connected via the solder 26. The wiring pattern 14 is electrically connected to the first electrode 107 (not shown in FIG. 20) of the surface emitting semiconductor laser 100. The wiring pattern 34 and the wiring pattern 64 formed on the semiconductor chip 20 are electrically connected via the solder 26. The wiring pattern 34 is electrically connected to the first electrode 107 (not shown in FIG. 20) of the surface emitting semiconductor laser 100. The third electrode 116 and the fourth electrode 110 (not shown in FIG. 20) of the surface emitting semiconductor laser 100 are electrically connected to a wiring pattern (not shown).

  The surface emitting semiconductor laser 100 can be mounted face-down on the semiconductor chip 20. By doing so, not only can the electrical connection be made by the solder 26, but also the surface emitting semiconductor laser 100 and the semiconductor chip 20 can be fixed. Note that a wire or a conductive paste may be used for the connection between the wiring pattern 14 and the wiring pattern 24 and the connection between the wiring pattern 34 and the wiring pattern 64.

  An underfill material 40 may be provided between the surface emitting semiconductor laser 100 and the semiconductor chip 20. When the underfill material 40 covers the emission surface 108 of the surface emitting semiconductor laser 100, the underfill material 40 is preferably transparent. The underfill material 40 covers and protects the electrical connection portion between the surface emitting semiconductor laser 100 and the semiconductor chip 20 and also protects the surfaces of the surface emitting semiconductor laser 100 and the semiconductor chip 20. Further, the underfill material 40 maintains the bonding state between the surface emitting semiconductor laser 100 and the semiconductor chip 20.

  A hole (for example, a through hole) 28 may be formed in the semiconductor chip 20. An optical fiber 30 is inserted into the hole 28. The hole 28 is formed from the surface on which the electrode 22 is formed to the surface on the opposite side, avoiding an internal circuit. A taper 29 is preferably formed at at least one open end of the hole 28. By forming the taper 29, the optical fiber 30 can be easily inserted into the hole 28.

  The semiconductor chip 20 may be attached to the substrate 42. More specifically, the semiconductor chip 20 may be attached to the substrate 42 via the adhesive 44. A hole 46 is formed in the substrate 42. The hole 46 is formed at a position communicating with the hole 28 of the semiconductor chip 20. The adhesive 44 that bonds the semiconductor chip 20 and the substrate 42 is provided so as not to block the communication between the two holes 28 and 46. The hole 46 of the substrate 42 has a tapered shape so that the inner diameter increases in the direction opposite to the semiconductor chip 20. Thereby, it becomes easy to insert the optical fiber 30.

  The substrate 42 may be formed of an insulating material such as resin, glass, or ceramic, but may be formed of a conductive material such as metal. When the substrate 42 is made of a conductive material, it is preferable to form the insulating film 43 at least on the surface to which the semiconductor chip 20 is attached. Note that the same material can be used for the substrate 42 in the following embodiments.

  The substrate 42 preferably has high thermal conductivity. According to this, the substrate 42 promotes the heat dissipation of at least one of the surface emitting semiconductor laser 100 and the semiconductor chip 20. In this case, the substrate 42 is a heat sink or a heat spreader. In the present embodiment, since the semiconductor chip 20 is bonded to the substrate 42, the semiconductor chip 20 can be directly cooled. The adhesive 44 that bonds the semiconductor chip 20 and the substrate 42 preferably has thermal conductivity. Furthermore, since the semiconductor chip 20 is cooled, the surface emitting semiconductor laser 100 bonded to the semiconductor chip 20 is also cooled.

  A wiring pattern 48 is provided on the substrate 42. The substrate 42 is provided with external terminals 50. In the present embodiment, the external terminal 50 is a lead. The wiring pattern 48 formed on the substrate 42 is electrically connected to at least one of the electrode 22 of the semiconductor chip 20 and the wiring patterns 24 and 64 formed on the semiconductor chip 20 through, for example, the wire 52. . Further, the wiring pattern 48 may be electrically connected to the external terminal 50.

  The optical fiber 30 is inserted into the hole 28 of the semiconductor chip 20. The optical fiber 30 is also inserted into the hole 46 of the substrate 42. The inner diameter of the hole 46 gradually decreases toward the hole 28 of the semiconductor chip 20, and the inner diameter of the opening of the hole 46 is larger than that of the optical fiber 30 on the surface opposite to the semiconductor chip 20. . The gap between the optical fiber 30 and the inner surface of the hole 46 is preferably filled with a filler 54 such as resin. The filler 54 also has a function to fix the optical fiber 30 and prevent it from coming off.

  The optical fiber 30 may be a single mode fiber or a multimode fiber. When the surface emitting semiconductor laser 100 emits multimode light, the light emitted from the surface emitting semiconductor laser 100 can be reliably introduced into the optical fiber 30 by using a multimode fiber as the optical fiber 30. it can.

  In the optical module 500 of the present embodiment, the surface emitting semiconductor laser 100 and the semiconductor chip 20 are sealed with a resin 56. The resin 56 also seals an electrical connection portion between the surface emitting semiconductor laser 100 and the semiconductor chip 20 and an electrical connection portion between the semiconductor chip 20 and the wiring pattern 48 formed on the substrate 42.

[Fifth Embodiment]
FIG. 21 is a diagram showing an optical transmission apparatus according to a fifth embodiment to which the present invention is applied. The light transmission device 90 connects electronic devices 92 such as a computer, a display, a storage device, and a printer to each other. The electronic device 92 may be an information communication device. The light transmission device 90 may be one in which plugs 96 are provided at both ends of the cable 94. The cable 94 includes the optical fiber 30 (see FIG. 20). The plug 96 incorporates the surface emitting semiconductor laser 100 and the semiconductor chip 20. Since the optical fiber 30 is built in the cable 94 and the surface emitting semiconductor laser 100 and the semiconductor chip 20 are built in the plug 96, they are not shown in FIG. The attachment state of the optical fiber 30 and the surface emitting semiconductor laser 100 is as described in the fourth embodiment.

  The surface emitting semiconductor laser 100 of the first embodiment is provided at one end of the optical fiber 30, and a light receiving element (not shown) is provided at the other end of the optical fiber 30. It has been. The light receiving element converts the input optical signal into an electrical signal, and then inputs the electrical signal to one electronic device 92. On the other hand, the electrical signal output from the electronic device 92 is converted into an optical signal by the surface emitting semiconductor laser 100. This optical signal travels through the optical fiber 30 and is input to the light receiving element.

  As described above, according to the light transmission device 90 of the present embodiment, information transmission between the electronic devices 92 can be performed by an optical signal.

[Sixth Embodiment]
FIG. 22 is a diagram showing a usage pattern of the optical transmission apparatus according to the sixth embodiment to which the present invention is applied. The light transmission device 90 is connected between the electronic devices 80. As the electronic device 80, a liquid crystal display monitor or a digital CRT (may be used in the fields of finance, mail order, medical care, education), a liquid crystal projector, a plasma display panel (PDP), a digital TV, a retail store A cash register (for POS (Point of Sale Scanning)), a video, a tuner, a game device, a printer, and the like can be given.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and results). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

  For example, in the surface emitting semiconductor laser of the above embodiment, the case where the light emitting element portion has one columnar portion has been described. However, even if the light emitting element portion includes a plurality of columnar portions, the embodiment of the present invention is impaired. I can't. Further, even when a plurality of surface emitting semiconductor lasers are arrayed, the same operation and effect are obtained.

  Further, for example, in the above embodiment, even if the p-type and n-type in each semiconductor layer are interchanged, it does not depart from the spirit of the present invention. In the above embodiment, AlGaAs-based materials have been described. However, other material materials such as GaInP-based materials, ZnSSe-based materials, InGaN-based materials, AlGaN-based materials, InGaAs-based materials, GaInNAs-based materials, and GaAsSb-based semiconductor materials are used. It is also possible to use. When the surface emitting semiconductor laser of the present invention is formed using a semiconductor material such as GaAsSb, InGaAs, or GaInNAs, and a long wavelength laser beam is generated in the active layer, the second region of the second mirror is used. By reducing the concentration of impurities contained in the first region, Auger non-radiative recombination in the second region of the second mirror can be reduced. As a result, the light emission efficiency of the surface emitting semiconductor laser can be dramatically increased.

1 is a cross-sectional view schematically showing a surface emitting semiconductor laser according to a first embodiment of the present invention. FIG. 2 is a plan view schematically showing the surface emitting semiconductor laser shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the surface emitting semiconductor laser shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the surface emitting semiconductor laser shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the surface emitting semiconductor laser shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the surface emitting semiconductor laser shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the surface emitting semiconductor laser shown in FIG. 1. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the surface emitting semiconductor laser shown in FIG. 1. FIG. 9A to FIG. 9D are diagrams schematically showing a method of connecting each electrode of the surface emitting semiconductor laser shown in FIG. FIG. 10 is a plan view schematically showing each electrode structure of the surface-emitting type semiconductor laser shown in FIG. 1 when the connection method shown in FIG. 9A is used. It is a figure which shows typically the cross section along the AA of the surface emitting semiconductor laser shown in FIG. It is a figure which shows typically the cross section along the BB line of the surface emitting semiconductor laser shown in FIG. It is a figure which shows typically the cross section along CC line of the surface emitting semiconductor laser shown in FIG. It is a top view which shows typically each electrode structure of the surface emitting semiconductor laser shown in FIG. 1 at the time of using the connection method shown in FIG.9 (b). It is a top view which shows typically each electrode structure of the surface emitting semiconductor laser shown in FIG. 1 at the time of using the connection method shown in FIG.9 (c). FIG. 10 is a plan view schematically showing each electrode structure of the surface emitting semiconductor laser shown in FIG. 1 when the connection method shown in FIG. 9D is used. It is sectional drawing which shows typically the surface emitting semiconductor laser of the 2nd Embodiment of this invention. FIG. 18 is a plan view schematically showing the surface emitting semiconductor laser shown in FIG. 17. It is sectional drawing which shows typically the surface emitting semiconductor laser of the 3rd Embodiment of this invention. It is a figure which shows typically the optical module which concerns on the 4th Embodiment of this invention. It is a figure which shows typically the light transmission apparatus which concerns on the 5th Embodiment of this invention. It is a figure which shows typically the usage type of the optical transmission apparatus which concerns on the 6th Embodiment of this invention. It is sectional drawing which shows typically an example of a well-known surface emitting semiconductor laser.

Explanation of symbols

  14, 24, 34, 48, 64 wiring pattern, 20 semiconductor chip, 26 solder, 28, 46 hole, 29 taper, 30 optical fiber, 30a end face of optical fiber, 40 underfill material, 42 substrate, 43 insulating film, 44 Adhesive, 50 external terminal, 52 wire, 54 filler, 56 resin, 80, 92 electronic device, 90 light transmission device, 94 cable, 96 plug, 100, 200, 300 surface emitting semiconductor laser, 101, 201 semiconductor substrate 101a, front surface of semiconductor substrate 101, 101b, back surface of semiconductor substrate 101, 102, 202 first mirror, 103, 203 active layer, 104, 204 second mirror, 104a, 204a first region, 104b, 204b second region, 104x First area 104 105, 205 current confinement layer, 106a, 106b, 106c insulating layer, 107, 207 first electrode, 108, 208 emission surface, 109, 209 second electrode, 110, 210 fourth electrode, 111, 211 first Contact layer, 112, 212 Light absorption layer, 113, 213 Second contact layer, 113a Upper surface of second contact layer 113, 114, 214 opening, 116, 216 Third electrode, 120, 220 Photodetection part, 130 Columnar part , 140, 240 Light-emitting element part, 150 Semiconductor multilayer film, 160a, 160b, 160c, 160d Electrode bonding part, 201a Front surface of semiconductor substrate 201, 201b Back surface of semiconductor substrate 201, 305 Reflective layer, 500 optical module, R1, R2, R3 resist layer

Claims (15)

A light emitting element portion;
A light detecting portion provided on the light emitting element portion and having an emission surface,
The light-emitting element unit includes a first conductive type first mirror, an active layer provided above the first mirror, and a distributed reflection type second mirror provided above the active layer,
The second mirror includes a first region of a first conductivity type and a second region,
The second region is in contact with the light detection unit;
The second region has a higher resistance than the first region,
The photodetecting unit includes a first conductivity type first contact layer, a light absorption layer provided above the first contact layer, and a first conductivity type second provided above the light absorption layer. A surface emitting semiconductor laser comprising: a contact layer; In claim 1,
And a first electrode and a second electrode for driving the light emitting element portion,
The surface emitting semiconductor laser, wherein the second electrode is in contact with the first region. In claim 1 or 2,
The surface emitting semiconductor laser, wherein the thickness of the second region is 1 μm or more. In any of claims 1 to 3,
The first region and the second region include a first conductivity type impurity,
The surface emitting semiconductor laser, wherein the concentration of the first conductivity type impurity in the second region is lower than the concentration of the first conductivity type impurity in the first region. In claim 4,
The surface emitting semiconductor laser, wherein the concentration of the first conductivity type impurity in the second region is less than 1 × 10 ¹⁶ [cm ⁻² ]. In claim 4 or 5,
The surface emitting semiconductor laser, wherein the second region is semi-insulating by further containing a second conductivity type impurity. In any of claims 1 to 3,
The surface emitting semiconductor laser, wherein the second region is made of an intrinsic semiconductor. In any one of Claims 1 thru | or 7,
The surface emitting semiconductor laser, wherein the first region includes a current confinement layer. In any of claims 1 to 8,
The surface emitting semiconductor laser, wherein the second region includes a spontaneous emission light reflecting layer. In any one of Claim 1 thru | or 9,
The light detection unit is a surface emitting semiconductor laser having a function of converting a part of light generated in the light emitting element unit into a current. In any of claims 2 to 10,
Furthermore, it includes a third electrode and a fourth electrode for driving the light detection unit,
A surface-emitting type semiconductor laser in which one of the first electrode and the second electrode and one of the third electrode and the fourth electrode are electrically connected at an electrode junction. In claim 11,
The electrode junction part is a surface emitting semiconductor laser provided in a region up to the electrode pad excluding the light emitting element part and the light detection part. In any of claims 1 to 12,
The light emitting element portion and the light detection portion are a surface emitting semiconductor laser having a pnpn structure or an npnp structure as a whole.   An optical module comprising the surface-emitting type semiconductor laser according to claim 1 and an optical waveguide.   An optical transmission device comprising the optical module according to claim 14.

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