JP6908367B2 - Infrared light emitting element - Google Patents

Description

The present invention relates to an infrared light emitting device.

An infrared light emitting diode (LED: Light Emitting Diode) forms a so-called pn junction diode structure in a semiconductor having a band gap capable of emitting infrared rays of a specific wavelength, and a forward current is passed through the pn junction diode to join the junction. In the depleted layer in the part, infrared rays are emitted by recombining electrons and holes.
Patent Document 1 states that in an infrared light emitting device composed of an n-type compound semiconductor layer and a p-type doped π layer, an n-type compound semiconductor layer and a π layer are formed between the n-type compound semiconductor layer and the π layer. It is also described that an n-type wide bandgap layer having a large bandgap is provided. As a result, the diffusion of holes generated by thermal excitation at room temperature in the n-type compound semiconductor layer in the π layer direction is suppressed, the dark current of the pn diode due to holes is reduced, and the holes are generated by thermal excitation on the π layer side. By suppressing the diffusion of the holes into the n-type compound semiconductor layer, an infrared light emitting device having a high diode resistance is realized in which the diffusion current of the pn diode is also reduced.

International Publication No. 2009/113685 Pamphlet

The infrared light emitting device is required to have both improved light emitting characteristics and mass productivity, but the infrared light emitting device described in Patent Document 1 has room for improvement in this respect.
An object of the present invention is to provide an infrared light emitting device having improved both light emitting characteristics and mass productivity.

In order to solve the above problems, the infrared light emitting device of the first aspect of the present invention is composed of a substrate, an n-type contact layer formed on the substrate, and a compound semiconductor layer containing AlInAsSb as a main component, and is an n-type contact layer. An active layer formed on the n-type barrier layer composed of an n-type barrier layer formed above and a compound semiconductor layer containing InAs _x Sb _{(1-x) (0 ≦ x ≦ 1) as a main component, and AlGaSb.} It is provided with a p-type barrier layer formed on the active layer, which is composed of a compound semiconductor layer containing the above as a main component.

In order to solve the above problems, the infrared light emitting device of the second aspect of the present invention is composed of a substrate, a p-type contact layer formed on the substrate, and a compound semiconductor layer containing AlGaSb as a main component, and is a p-type contact layer. An active layer formed on the p-type barrier layer composed of a p-type barrier layer formed above and a compound semiconductor layer containing InAs _x Sb _{(1-x) (0 ≦ x ≦ 1) as a main component, and AlInAsSb.} It is provided with an n-type barrier layer formed on the active layer, which is composed of a compound semiconductor layer containing the above as a main component.

The "compound semiconductor layer containing XX as a main component" means "a compound semiconductor layer substantially composed of XX, except for dopants and impurities inevitably mixed during film formation".

According to the first aspect and the second aspect of the present invention, an infrared light emitting device having improved both light emitting characteristics and mass productivity can be obtained.

It is sectional drawing which shows the structure of the infrared light emitting element of the 1st aspect. It is sectional drawing which shows the structure of the infrared light emitting element of the 2nd aspect. It is sectional drawing which shows the structure of the infrared light emitting element of 1st Embodiment. It is sectional drawing which shows the structure of the infrared light emitting element of 2nd Embodiment.

[First aspect]
<Structure>
As shown in FIG. 1, the infrared light emitting element of the first aspect includes the substrate 1, the n-type contact layer 2 formed on one surface (on the substrate) of the substrate 1, and the substrate of the n-type contact layer 2. The n-type barrier layer 3 formed on the opposite surface (on the n-type contact layer) and the n-type barrier layer 3 formed on the opposite surface (on the n-type barrier layer) to the n-type contact layer 2. It includes an active layer 4 and a p-type barrier layer 5 formed on a surface (on the active layer) opposite to the n-type barrier layer 3 of the active layer 4. The n-type barrier layer 3 is composed of a compound semiconductor layer containing AlInAsSb as a main component. The active layer 4 is _{composed of a compound semiconductor layer containing InAs x} Sb _(1-x) (0 ≦ x ≦ 1) as a main component. The p-type barrier layer 5 is composed of a compound semiconductor layer containing AlGaSb as a main component.

<Action, effect>
According to the infrared light emitting device of the first aspect, the p-type barrier layer composed of a compound semiconductor layer containing AlGaSb as a main component and the n-type barrier layer composed of a compound semiconductor layer containing AlInAsSb as a main component are provided. The band offset of the conductor between the active layer and the p-type barrier layer and the band offset of the valence band between the active layer and the n-type barrier layer can be sufficiently increased.
Further, by using a compound semiconductor containing AlGaSb as a main component as the material of the p-type barrier layer and a compound semiconductor containing AlInAsSb as the main component as the material of the n-type barrier layer, Si is used as both the n-type dopant and the p-type dopant. Becomes available. Si is a non-toxic Group IV element that is easy to control due to its low vapor pressure.
As a result, the infrared light emitting device of the first aspect has an improved barrier function due to the barrier layer and is excellent in dopant controllability when forming each layer. That is, according to the first aspect of the present invention, an infrared light emitting device having improved both light emitting characteristics and mass productivity can be obtained.

<Preferable form>
In the infrared light emitting device of the first aspect, the n-type dopant contained in the n-type contact layer, the n-type dopant contained in the n-type barrier layer, and the p-type dopant contained in the p-type barrier layer are preferably Si.
In the infrared light emitting device of the first aspect, it is preferable that the substrate is a GaAs substrate and further includes a buffer layer made of a compound semiconductor layer containing AlGaSb as a main component and formed between the substrate and the n-type contact layer.
The infrared light emitting device of the first aspect preferably further includes a p-type contact layer formed on a p-type barrier layer composed of a compound semiconductor layer containing GaSb or GaInSb as a main component. The p-type dopant contained in the p-type contact layer is preferably Si.

[Second aspect]
<Structure>
As shown in FIG. 2, the infrared light emitting element of the first aspect includes the substrate 1, the p-type contact layer 6 formed on one surface (on the substrate) of the substrate 1, and the substrate of the p-type contact layer 6. The p-type barrier layer 5 formed on the opposite surface (on the p-type contact layer) and the p-type barrier layer 5 formed on the opposite surface (on the p-type barrier layer) to the p-type contact layer 6. It includes an active layer 4 and an n-type barrier layer 3 formed on a surface (on the active layer) opposite to the p-type barrier layer 5 of the active layer 4. The n-type barrier layer 3 is composed of a compound semiconductor layer containing AlInAsSb as a main component. The active layer 4 is _{composed of a compound semiconductor layer containing InAs x} Sb _(1-x) (0 ≦ x ≦ 1) as a main component. The p-type barrier layer 5 is composed of a compound semiconductor layer containing AlGaSb as a main component.

<Action, effect>
According to the infrared light emitting device of the second aspect, a p-type barrier layer composed of a compound semiconductor layer containing AlGaSb as a main component and an n-type barrier layer composed of a compound semiconductor layer containing AlInAsSb as a main component are provided. The band offset of the conductor between the active layer and the p-type barrier layer and the band offset of the valence band between the active layer and the n-type barrier layer can be sufficiently increased.
Further, by using a compound semiconductor containing AlGaSb as a main component as the material of the p-type barrier layer and a compound semiconductor containing AlInAsSb as the main component as the material of the n-type barrier layer, Si is used as both the n-type dopant and the p-type dopant. Becomes available. Si is a non-toxic Group IV element that is easy to control due to its low vapor pressure.
As a result, the infrared light emitting device of the second aspect has an improved barrier function due to the barrier layer and is excellent in dopant controllability when forming each layer. That is, according to the second aspect of the present invention, an infrared light emitting device having improved both light emitting characteristics and mass productivity can be obtained.

<Preferable form>
In the infrared light emitting device of the second aspect, the p-type dopant contained in the p-type contact layer, the p-type dopant contained in the p-type barrier layer, and the n-type dopant contained in the n-type barrier layer are preferably Si.
In the infrared light emitting device of the second aspect, it is preferable that the substrate is a GaAs substrate and the p-type contact layer is a compound semiconductor layer containing GaSb as a main component.
The infrared light emitting device of the second aspect preferably further includes an n-type contact layer formed on an n-type barrier layer composed of a compound semiconductor layer containing InAsSb as a main component. The n-type dopant in the n-type contact layer is preferably Si.

[Common to the first and second aspects]
<Background to knowledge>
The barrier layer plays an important role in realizing an infrared light emitting device having good characteristics. The barrier layer is a layer formed in contact with the active layer and has a function of preventing diffusion current. The p-type barrier layer preferably has a sufficiently large band offset of the conduction band with the active layer. The n-type barrier layer preferably has a sufficiently large band offset of the valence band from the active layer. Since the diffusion length of electrons is longer than that of holes, it is preferable that the thickness of the barrier layer is sufficiently thick, especially in the p-type barrier layer.

As the material of the barrier layer, it is conceivable to select a material having a bandgap larger than that of the active layer. However, by adding a certain amount of Al or Ga to the material of the active layer and increasing the mixed crystal composition, the bandgap, In many cases, the band offset of the conduction band and the band offset of the valence band are greatly earned.
However, the larger the mixed crystal composition of Al and Ga in the barrier layer, the larger the lattice mismatch with the active layer tends to be, and as a result, the critical film thickness of the barrier layer becomes smaller. The problem arises that the barrier layer cannot be formed. That is, especially in the p-type barrier layer, it is important to select a material having a lattice constant close to that of the active layer and a large band offset of the conduction band.

In the infrared light emitting devices of the first aspect and the second aspect, by using AlGaSb as the material of the p-type barrier layer, the band offset of the conduction band with the active layer can be made large. Further, since AlGaSb has a lattice constant close to that of InAsSb, which is the material of the active layer, it is possible to increase the film thickness of the p-type barrier layer. Further, by using AlInAsSb as the material of the n-type barrier layer, it is possible to increase the band offset of the valence band with the active layer. This makes it possible to enhance the function of preventing the diffusion current and improve the characteristics of the infrared light emitting element.

As the p-type dopant used when forming the p-type barrier layer, Be, Zn, Cd, C, Mg, Ge and the like are generally used. In particular, Zn is preferably used because it has a high activation rate and low toxicity. However, there are concerns that Zn has a high vapor pressure and is difficult to control, and remains in the chamber. Further, if the n-type dopant and the p-type dopant can be made the same, the mass productivity will be improved.
In the infrared light emitting device of the first aspect and the second aspect, AlInAsSb was used as the material of the n-type barrier layer, and AlGaSb was used as the material of the p-type barrier layer. , Si can be used as the dopant. Since Si is a highly controllable dopant, it becomes easy to form each compound semiconductor layer at a desired doping concentration. Further, since both the n-type barrier layer and the p-type barrier layer can be doped with a single dopant, the mass productivity is also excellent.

<Manufacturing method>
The infrared light emitting devices of the first aspect and the second aspect are manufactured through a step of forming each layer on a substrate, and this step is, for example, a molecular beam epitaxy (MBE) method or an organometallic vapor phase epitaxy (MOVPE). It can be done by law.

<Additional configuration>
The infrared light emitting device of the first aspect and the second aspect may further include an electrode formed on the n-type barrier layer and the p-type contact layer, and a passivation film.
A plurality of infrared light emitting elements of the first aspect and the second aspect may be formed on a substrate and electrically connected in series. With such a structure, it is possible to add the outputs of a single infrared light emitting element, and the output can be dramatically improved.
Further, the infrared light emitting element of the first aspect or the second aspect and the integrated circuit unit for driving the infrared light emitting element may be formed in a hybrid manner in the same package. The electrical connection method between the infrared light emitting element and the integrated circuit unit is not particularly limited. The package is not particularly limited as long as it is a material having a high infrared transmittance, and a hollow package or the like may be used.

<Details of each configuration>
(substrate)
The substrate is not particularly limited as long as it can grow a compound semiconductor layer on it, and a GaAs substrate, a single crystal substrate such as a Si substrate, or the like is preferable. Further, those single crystal substrates may be doped into n-type or p-type by donor impurities or acceptor impurities.
The plane orientation of the single crystal substrate is not particularly limited, but (100), (111), (110) and the like are preferable. It is also possible to use a plane orientation tilted by 1 ° to 5 ° with respect to these plane orientations.

When a plurality of infrared light emitting elements formed on the surface of the substrate are connected in series by electrodes, it is preferable that each infrared light emitting element is insulated and separated in a portion other than the electrodes. Therefore, as the substrate, it is preferable to use a semi-insulating substrate or a substrate capable of insulatingly separating the laminate of each layer formed on the substrate and the substrate.
Further, by using a material that transmits infrared rays as the substrate, infrared rays can be taken out from the back surface side of the substrate. In this case, infrared light is not blocked by the electrodes, which is preferable. As the material of such a substrate, semi-insulating Si, GaAs, or the like is preferable.
For the purpose of flattening and cleaning the surface of the substrate as is usually performed, a semiconductor layer made of the same material as the substrate may be formed on the substrate and used as the substrate. The use of a GaAs layer formed on a GaAs substrate as a substrate is the most typical example of this.

(Buffer layer)
The infrared light emitting device of the first aspect preferably further includes a buffer layer between the substrate and the n-type contact layer. The buffer layer is formed on the surface of the substrate. The buffer layer functions as a layer for improving all the crystallinity formed on the buffer layer. Thereby, an active layer having good crystallinity (less defects) can be obtained.
Further, in the infrared light emitting device of the second aspect, a buffer layer may be further provided between the substrate and the p-type contact layer.

Examples of the buffer layer material include InSb, InAs, InAsSb, AlInSb, GaInSb, AlGaInSb, AlInAsSb, GaInAsSb, AlGaInAsSb, AlSb, GaSb, AlGaSb, AlAsSb, GaAsSb, and AlGaAsSb. The buffer layer may be a single layer made of one of these materials, or may be a multilayer in which a plurality of layers are laminated. Further, a graded buffer layer formed so as to bring the lattice constant closer to the composition of the layer (n-type contact layer or p-type contact layer) formed on the lattice constant while continuously or stepwise changing the composition of the material. May be used.

The GaSb monolayer film and the AlGaSb monolayer film can (a) easily form a film having good crystallinity, (b) can bring the lattice mismatch with the active layer containing InAsSb close to zero, (c). A single-layer film is preferable as a material for a buffer layer from the viewpoint that the film thickness can be thinner than that of a graded layer or the like and the formation time can be shortened.
When the buffer layer is an AlGaSb monolayer film, the electrical resistance tends to increase but the crystallinity tends to deteriorate as the Al composition ratio y of _{Al y} Ga _{(1-y) Sb (0 ≦ y ≦ 1) increases.} Therefore, the Al composition ratio y is appropriately selected according to the desired resistance and crystallinity. If _{the Al composition ratio y of Al y} Ga _(1-y) Sb (0 ≦ y ≦ 1) is too large, oxidative corrosion is likely to occur. Therefore, from the viewpoint of easiness of oxidation and corrosion, the Al composition ratio y is set to 0. It is preferably 0.8 or more and 0.8 or less.

Further, since the GaSb monolayer film can be formed into a film having better crystallinity than the AlGaSb monolayer film, it is more preferable to use the GaSb monolayer film from the viewpoint of obtaining good crystallinity.
In the preferred embodiment of the infrared light emitting device of the first aspect, "a configuration in which the substrate is a GaAs substrate and a buffer layer composed of a compound semiconductor layer containing AlGaSb as a main component is further provided between the substrate and the n-type contact layer". By using AlGaSb as a material for the buffer layer and increasing the Al composition ratio as described above to increase the electrical resistance of the buffer layer, the buffer layer functions as a non-doped insulating layer. This is preferable because the buffer layer can be a layer that does not contribute to the PIN structure.

If the film thickness of the buffer layer is too thin, the effect of improving the crystallinity of the active layer will be lost, and if it is too thick, it will take time to form and the mesa etching process for element separation will be difficult. Is preferable.
When the GaSb monolayer film and the AlGaSb monolayer film are used as the buffer layer, they may be non-doped, or may be doped into n-type or p-type.
When the n-type contact layer is formed on the buffer layer, the n-type contact layer may be formed on the non-doped GaSb or AlGaSb monolayer film, or the n-type doped GaSb or AlGaSb monolayer film may be formed as it is. It may also be used as an n-type contact layer.

However, in order to form an n-type monolayer film of GaSb or AlGaSb, Group IV elements such as Si and Sn, which have a low vapor pressure, cannot be used because they act as p-type dopants, and have a high vapor pressure and are toxic. Some VI elements such as Te must be used. When Te or the like is used, it is difficult to control it because the vapor pressure is high, or there is a concern that the chamber of the film forming apparatus may be contaminated.
That is, when forming an n-type contact layer on the buffer layer, it is preferable to use a non-doped GaSb or AlGaSb monolayer film as the buffer layer.
On the other hand, when the p-type contact layer is formed on the buffer layer, the p-type doped GaSb and AlGaSb monolayer films may be used as they are as the p-type contact layer. Regarding the p-type formation of the monolayer film of GaSb and AlGaSb, it is preferable because the vapor pressure is low and Si, which is the most commonly used Group IV element, can be used as a dopant.

(N-type contact layer)
The n-type contact layer functions as a contact layer with an electrode. Examples of the material of the n-type contact layer include InSb, InAs, InAsSb, AlInSb, GaInSb, AlGaInSb, AlInAsSb, GaInAsSb, AlGaInAsSb, AlSb, GaSb, AlGaSb, AlAsSb, GaAsSb, and AlGaAsSb.
Since the sheet resistance of the n-type contact layer causes Johnson noise, which is thermal noise, the sheet resistance should be as small as possible. The n-type contact layer needs to be adequately doped to reduce contact resistance. Therefore, the doping concentration ^{is preferably 1 × 10 18} / cm ³ or more. Examples of the n-type dopant include Si, Sn, S, Se, Te, and Ge.

As the material of the n-type contact layer, (d) Si, which has a lattice constant close to that of InAsSb forming the active layer, (e) has a low vapor pressure, and is the most commonly used Group IV element, can be used as a dopant. , (F) InAs or InAsSb is particularly preferable from the viewpoint that the sheet resistance can be reduced. It is more preferable to use InAsSb, which is the same material as the active layer, because the lattice constants can be completely matched.
The film thickness of the n-type contact layer is preferably as thick as possible in order to reduce the sheet resistance. However, if it is too thick, it takes time to form and the mesa etching process for element separation becomes difficult. Therefore, the film thickness of the n-type contact layer is preferably 0.1 μm or more and 1 μm or less as a preferable range.

(N-type barrier layer)
The n-type barrier layer of the first aspect and the second aspect infrared light emitting device is composed of a compound semiconductor layer containing AlInAsSb as a main component, and has a function of preventing a diffusion current from the active layer. By using AlInAsSb, which has a large band gap with respect to the active layer made of InAsSb, as the n-type barrier layer, a large band offset of the valence band can be obtained.
When the lattice constants of the active layer and the n-type barrier layer are different, if the film thickness of the n-type barrier layer exceeds the critical film thickness, the crystallinity of the n-type barrier layer deteriorates. Alternatively, it is necessary to consider both the band offset of the valence band and the deterioration of crystallinity. From the viewpoint of increasing the film thickness of the n-type barrier layer, it is preferable that the difference between the lattice constants of the active layer and the n-type barrier layer is as small as possible.

In addition, the n-type barrier layer can lower the upper end of the valence band by n-type doping, and functions more effectively as a diffusion barrier for thermally excited holes. Therefore, the n-type barrier layer needs to be sufficiently doped, and the doping concentration is preferably 1 × 10 ¹⁸ / cm ³ or more. Examples of the n-type dopant include Si, Sn, S, Se, Te, and Ge.
By using AlInAsSb as the material of the n-type barrier layer, the lattice constants of the active layer made of InAsSb and the n-type barrier layer become close to each other, the vapor pressure is low, and Si, which is the most commonly used Group IV element, can be obtained. It can be used as an n-type dopant.

In this case, if the Al composition ratio of AlInAsSb is too small, a sufficient band offset of the valence band cannot be secured, and if the Al composition ratio of AlInAsSb is too large, the difference in lattice constant from the active layer containing InAsSb becomes large. Since the critical film thickness of the n-type barrier layer becomes small, it becomes impossible to secure a sufficient film thickness as the n-type barrier layer. Therefore, the Al composition ratio of AlInAsSb is preferably 0.1 or more and 0.5 or less.
The film thickness of the n-type barrier layer should be as thin as possible in order to reduce the resistance of the infrared light emitting element, but the film thickness must be such that tunnel leakage does not occur between the electrode and the active layer. Therefore, the film thickness of the n-type barrier layer is preferably 0.01 μm or more, more preferably 0.02 μm or more. The upper limit of the film thickness of the n-type barrier layer is limited by the critical film thickness determined by the difference between the lattice constants of the active layer and the n-type barrier layer.

(Active layer)
The active layer of the first aspect and the second aspect infrared light emitting device is composed of InAs _x Sb _(1-x) (0 ≦ x ≦ 1). The As composition ratio x of the active layer is not particularly limited, but by setting the As composition ratio x to a desired value, it is possible to control the peak wavelength of infrared emission over a wide range of 3 μm to 10 μm. When AlGaSb and GaSb are used as the buffer layer, better crystals can be obtained when the lattice constant of InAsSb in the active layer is closer to the lattice constant of the buffer layer. Therefore, the As composition ratio x is 0.7 or more and 1 or less. preferable.
The thickness of the active layer is preferably thick in order to increase the amount of light emission, but if it is too thick, it takes time to form and the mesa etching process for element separation becomes difficult. Therefore, the film thickness is 0.5 μm or more and 3 μm or less. preferable.

The active layer may be non-doped, or may be n-type or p-type doped. Since InAsSb has a very small bandgap, the intrinsic carrier density is very large. This leads to an increase in diffusion current and a facilitation of the Auger recombination process. These effects can be reduced by doping the active layer to p-type. The amount of doping is set as appropriate.
As _{the p-type dopant of the active layer composed of InAs x} Sb _(1-x) (0 ≦ x ≦ 1), Be, Zn, Cd, C, Mg, Ge and the like are generally preferably used, but Zn is preferably used. It is more preferably used because it has a high activation rate and low toxicity.

(P-type barrier layer)
The p-type barrier layer of the first aspect and the second aspect infrared light emitting device is composed of a compound semiconductor layer containing AlGaSb as a main component, and has a function of preventing diffusion current from the active layer. By using AlGaSb, which has a large band gap with respect to the active layer made of InAsSb, as the material of the p-type barrier layer, a large band offset of the conduction band can be obtained.
In addition, the p-type barrier layer can raise the lower end of the conduction band by p-type doping, and functions more effectively as a diffusion barrier for thermally excited electrons. Therefore, the p-type barrier layer needs to be sufficiently doped, and the doping concentration is preferably 1 × 10 ¹⁸ / cm ³ or more.

Examples of the p-type dopant include Be, Zn, Cd, C, Mg, and Ge. Si is generally known as an n-type dopant, but can be used as a p-type dopant for AlGaSb.
By using AlGaSb as the material of the p-type barrier layer, the lattice constants of the active layer made of InAsSb and the p-type barrier layer become close to each other, the vapor pressure is low, and Si, which is the most commonly used Group IV element, can be obtained. It can be used as a p-type dopant, and the band offset of the conduction band can be increased.

Since the difference in lattice constant from InAsSb forming the active layer is sufficiently small, the Al composition ratio of AlGaSb in the p-type barrier layer is not restricted by the critical film thickness, but if the Al composition ratio is too large, there is a concern about oxidation and corrosion. Therefore, the Al composition ratio is preferably 0 or more and 0.8 or less.
The film thickness of the p-type barrier layer should be as thin as possible in order to reduce the element resistance of the light emitting element, but the film thickness must be such that tunnel leakage does not occur between the electrode and the active layer. Therefore, the film thickness of the p-type barrier layer is preferably 0.01 μm or more, more preferably 0.02 μm or more. The upper limit of the film thickness of the p-type barrier layer is limited by the critical film thickness determined by the difference between the lattice constants of the active layer and the n-type barrier layer.

(P-type contact layer)
The p-type contact layer functions as a contact layer with an electrode. Examples of the material of the p-type contact layer include InSb, InAs, InAsSb, AlInSb, GaInSb, AlGaInSb, AlInAsSb, GaInAsSb, AlGaInAsSb, AlSb, GaSb, AlGaSb, AlAsSb, GaAsSb, and AlGaAsSb.
Since the sheet resistance of the p-type contact layer causes Johnson noise, which is thermal noise, the sheet resistance should be as small as possible. The p-type contact layer needs to be adequately doped to reduce contact resistance. Therefore, the doping concentration ^{is preferably 1 × 10 18} / cm ³ or more. Examples of the p-type dopant include Be, Zn, Cd, C, Mg, and Ge.

As a material for the p-type contact layer, (d) Si, which has a lattice constant close to that of InAsSb forming the active layer, (e) has a low vapor pressure, and is the most commonly used Group IV element, can be used as a dopant. , (F) AlGaSb and GaSb are preferable from the viewpoint that the sheet resistance can be reduced. It is preferable that the material of the p-type contact layer is GaSb because the sheet resistance can be made smaller than that of AlGaSb.
Further, since lattice matching with InAsSb is possible by controlling the In composition, it is also preferable to use GaInSb as a material for the p-type contact layer.
The film thickness of the p-type contact layer is preferably as thick as possible in order to reduce the sheet resistance. However, if it is too thick, it takes time to form and the mesa etching process for element separation becomes difficult. Therefore, the film thickness of the p-type contact layer is preferably 0.1 μm or more and 1 μm or less as a preferable range.

(Passivation membrane)
The passivation film is not particularly limited as long as it is an insulating film. Examples of the material of the passivation film include a silicon nitride film (Si ₃ N ₄ ), a silicon oxide film (SiO ₂ ), and a silicon oxide nitride film (SiO N).
(electrode)
The electrodes include a p-type electrode that is electrically connected to the p-type contact layer and an n-type electrode that is electrically connected to the n-type contact layer. The electrode is not particularly limited as long as it is composed of a conductive film, and examples thereof include a laminated film (upper layer / lower layer) such as Au / Ti and Au / Cr.

[Embodiment]
Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments shown below. In the embodiments shown below, technically preferable limitations are made for carrying out the present invention, but this limitation is not an essential requirement of the present invention.
In the drawings used in the following description, the dimensional relationship of each part shown may differ from the actual dimensional relationship.

<First Embodiment>
(Constitution)
As shown in FIG. 3, the infrared light emitting device of the first embodiment includes a substrate 1, a buffer layer 7, an n-type contact layer 2, an n-type barrier layer 3, an active layer 4, and a p-type barrier layer 5. A p-type contact layer 6, an n-type electrode 8, a p-type electrode 9, and a passivation film 10 are provided.
A buffer layer 7, an n-type contact layer 2, an n-type barrier layer 3, an active layer 4, a p-type barrier layer 5, and a p-type contact layer 6 are formed on the substrate 1 in this order. That is, a compound semiconductor laminate composed of a buffer layer 7, an n-type contact layer 2, an n-type barrier layer 3, an active layer 4, a p-type barrier layer 5, and a p-type contact layer 6 is formed on the substrate 1. ..

The width of the buffer layer 7 and the n-type contact layer 2 is larger than the width of the n-type barrier layer 3, the active layer 4, the p-type barrier layer 5, and the p-type contact layer 6. That is, there is a step between the n-type contact layer 2 and the n-type barrier layer 3. The n-type electrode 8 is formed on the upper surface of the n-type contact layer 2 generated by this step, and the p-type electrode 9 is formed on the upper surface of the p-type contact layer 6.
The passivation film 10 covers the upper surface of the substrate 1, the side surfaces and the upper surface of the compound semiconductor laminate. The upper portions of the n-type electrode 8 and the p-type electrode 9 are exposed from the passivation film 10.

The substrate 1 is made of GaAs. The buffer layer 7 is made of AlGaSb. The n-type contact layer 2 is made of InAsSb containing Si (n-type dopant). The n-type barrier layer 3 is made of AlInAsSb containing Si (n-type dopant). The active layer 4 is composed of InAs _x Sb _(1-x) (0 ≦ x ≦ 1). The p-type barrier layer 5 is made of AlGaSb containing Si (p-type dopant). The p-type contact layer 6 is made of GaSb or GaInSb containing Si (p-type dopant). The n-type electrode 8 is made of Au / Ti. The p-type electrode 9 is made of Au / Ti. The passivation film 10 is made of silicon nitride.

(Action, effect)
According to the infrared light emitting device of the first embodiment, by providing the p-type barrier layer 5 made of AlGaSb containing Si, the band offset of the conductor between the active layer 4 and the p-type barrier layer 5 can be sufficiently increased. can. Further, by having the buffer layer 7 made of AlGaSb, _{the crystallinity of the active layer 4 made of InAs x} Sb _(1-x) (0 ≦ x ≦ 1) is improved. Further, since the n-type contact layer 2 is made of the same InAsSb as the active layer 4, the lattice constants of the n-type contact layer 2 and the active layer 4 are the same.

Further, since the n-type barrier layer 3 is _{composed of AlInAsSb having a large bandgap energy with respect to InAs x} Sb _(1-x) (0 ≦ x ≦ 1) forming the active layer 4, a large band offset of the valence band can be obtained. Further, the p-type contact layer 6 is composed of InAs _x Sb _(1-x) (0 ≦ x ≦ 1) forming the active layer 4 and GaSb having a lattice constant close to that of the active layer 4.
From the above, according to the infrared light emitting device of the first embodiment, good light emitting characteristics can be obtained.
Further, since the infrared light emitting device of the first embodiment uses controllable Si as both the n-type dopant and the p-type dopant, it is also excellent in mass productivity.

(Production method)
First, a buffer layer 7, an n-type contact layer 2, an n-type barrier layer 3, an active layer 4, a p-type barrier layer 5, and an MBE (molecular beam epitaxy) method are used on the upper surface of a GaAs wafer (base 1). The p-type contact layer 6 is formed. Next, the n-type barrier layer 3, the active layer 4, the p-type barrier layer 5, and the p-type contact layer 6 are partially removed for each element by wet etching with an acid or an ion milling method, and n A step is formed to make contact between the mold contact layer 2 and the n-type electrode 8. As a result, a plurality of compound semiconductor laminates having steps are formed on the GaAs wafer.

Next, mesa etching for element separation is performed on a plurality of compound semiconductor laminates having steps. Here, the n-type contact layer and the buffer layer appearing at the bottom of the step are sequentially and partially removed. As a result, the upper surface of the substrate 1 is exposed in the element separation region.
Next, the passivation film 10 made of silicon nitride covers the upper surface of the substrate 1 and the upper surface and side surfaces of the element-separated compound semiconductor laminate.
Next, the portion of the passivation film 10 that forms the n-type electrode 8 and the p-type electrode 9 is etched to form a through hole. Next, the Au / Ti electrode is formed so as to fill the through hole by a lift-off method or the like.

<Second embodiment>
(Constitution)
As shown in FIG. 4, the infrared light emitting element of the second embodiment includes a substrate 1, a p-type contact layer 6, a p-type barrier layer 5, an active layer 4, an n-type barrier layer 3, and an n-type contact. It includes a layer 2, an n-type electrode 8, a p-type electrode 9, and a passivation film 10.
A p-type contact layer 6, a p-type barrier layer 5, an active layer 4, an n-type barrier layer 3, and an n-type contact layer 2 are formed on the substrate 1 in this order. That is, a compound semiconductor laminate composed of a p-type contact layer 6, a p-type barrier layer 5, an active layer 4, an n-type barrier layer 3, and an n-type contact layer 2 is formed on the substrate 1. ..

The width of the p-type contact layer 6 is larger than the width of the p-type barrier layer 5, the active layer 4, the n-type barrier layer 3, and the n-type contact layer 2. That is, there is a step between the p-type contact layer 6 and the p-type barrier layer 5. The p-type electrode 9 is formed on the upper surface of the p-type contact layer 6 generated by this step, and the n-type electrode 8 is formed on the upper surface of the n-type contact layer 2.
The passivation film 10 covers the upper surface of the substrate 1, the side surfaces and the upper surface of the compound semiconductor laminate. The upper portions of the n-type electrode 8 and the p-type electrode 9 are exposed from the passivation film 10.

The substrate 1 is made of GaAs. The n-type contact layer 2 is made of InAsSb or InAs containing Si (n-type dopant). The n-type barrier layer 3 is made of AlInAsSb or InAs containing Si (n-type dopant). The active layer 4 is composed of InAs _x Sb _(1-x) (0 ≦ x ≦ 1). The p-type barrier layer 5 is made of AlGaSb containing Si (p-type dopant). The p-type contact layer 6 is made of GaSb containing Si (p-type dopant). The n-type electrode 8 is made of Au / Ti. The p-type electrode 9 is made of Au / Ti. The passivation film 10 is made of silicon nitride.

(Action, effect)
According to the infrared light emitting device of the second embodiment, by providing the p-type barrier layer 5 made of AlGaSb containing Si, the band offset of the conductor between the active layer 4 and the p-type barrier layer 5 can be sufficiently increased. can.
Further, since the n-type contact layer 2 is composed of the same InAsSb or InAs as the active layer 4, the lattice constants of the n-type contact layer 2 and the active layer 4 match. Further, since the n-type barrier layer 3 is composed of AlInAsSb or AlInAs having a large bandgap energy with respect _{to InAs x} Sb _{(1-x) (0 ≦ x ≦ 1) forming the active layer 4, the band offset of the valence band is large.} I can take it. Further, the p-type contact layer 6 is composed of InAs _x Sb _(1-x) (0 ≦ x ≦ 1) forming the active layer 4 and GaSb having a lattice constant close to each other, so that the InAs _x Sb _{(1) forming the active layer 4 is formed. -x)} The crystallinity of (0 ≦ x ≦ 1) can be improved.
From the above, according to the infrared light emitting device of the second embodiment, good light emitting characteristics can be obtained.
Further, since the infrared light emitting device of the second embodiment uses controllable Si as both the n-type dopant and the p-type dopant, it is also excellent in mass productivity.

(Production method)
Since the infrared light emitting device of the second embodiment has a different configuration of the compound semiconductor laminate from the infrared light emitting device of the first embodiment, the formation order of each layer is different, but basically the method described in the first embodiment is used. Can be manufactured.

Hereinafter, examples of the present invention will be described.
[Example 1]
An infrared light emitting device having the structure shown in FIG. 3 was manufactured as follows.
By the MBE method, a buffer layer 7, an n-type contact layer 2, an n-type barrier layer 3, an active layer 4, a p-type barrier layer 5, and p are placed on a substrate 1 made of a semi-insulating GaAs single crystal. By sequentially laminating the mold contact layers 6, a compound semiconductor laminate having a PIN structure was formed.
In this laminating step, a non-doped Al _0.55 Ga _0.45 Sb layer of 0.5 μm was formed as the buffer layer 7. As the n-type contact layer 2, 0.7 μm of an n-type InAs _0.91 Sb _0.09 ^{layer doped with Si 7 × 10 18} / cm ^{3 was formed.} As the n-type barrier layer 3, an n-type Al _0.3 In _0.7 As _0.91 Sb _0.09 ^{layer doped with Si 7 × 10 18} / cm ³ was formed by 0.02 μm. As the active layer 4, a non-doped InAs _0.91 Sb _0.09 layer was formed in an amount of 2 μm. As the p-type barrier layer 5, a p-type Al _0.4 Ga _0.6 ^{Sb layer doped with 3 × 10 18} / cm ^{3 of} Si was formed at 0.02 μm. As the p-type contact layer 6, 0.5 μm of a p-type GaSb layer doped with ^{3 × 10 18} / cm ^{3 of Si was formed.}

In this laminating step, since the vapor pressure is low, it is easy to control, and only Si, which is generally used without toxicity, is used as a dopant. That is, this method is a method excellent in mass productivity as a method for producing a compound semiconductor laminate having a PIN structure.
The full width at half maximum (FWHM value) of the locking curve of the X-ray diffraction peak of the active layer 4 made _{of InAs 0.91} Sb _{0.09 of the} obtained compound semiconductor laminate was evaluated to be 304 arcsec.
The infrared light emitting device of Example 1 was produced by performing the following steps on this compound semiconductor laminate.

First, a step was formed for making contact with the n-type contact layer 2 by wet etching with an acid, an ion milling method, or the like. Next, the compound semiconductor laminate having the steps formed was subjected to mesa etching for element separation. Then, the passivation film 10 made of SiN covered the upper surface of the substrate 1 and the upper surface and the side surface of the element-separated compound semiconductor laminate. Next, a through hole was formed in the electrode-forming portion of the passivation film 10. Next, Au / Ti was vapor-deposited on the stepped portion of the n-type contact layer 2 and on the p-type contact layer 6 by EB (electron beam), and the n-type electrode 8 and the p-type electrode were formed in each through hole by the lift-off method. 9 were formed respectively.
In this way, an infrared light emitting device having the structure shown in FIG. 3 was obtained.

[Example 2]
As the n-type contact layer 2, 0.7 μm of n-type InAs _0.87 Sb _0.13 ^{layer doped with Si 7 × 10 18} / cm ^{3 was formed.} Further, as the n-type barrier layer 3, an n-type Al _0.3 In _0.7 As _0.87 Sb _0.13 ^{layer doped with Si 7 × 10 18} / cm ³ was formed by 0.02 μm. Further, as the active layer 4, a non-doped InAs _0.87 Sb _0.13 layer was formed in an amount of 2 μm. Further, as the p-type contact layer 6, a p-type Ga _0.96 In _0.04 ^{Sb layer doped with 3 × 10 18} / cm ^{3 of} Si was formed in an amount of 0.5 μm. A compound semiconductor laminate having a PIN structure was formed by the same method as in Example 1 except for this.
The full width at half maximum (FWHM value) of the locking curve of the X-ray diffraction peak of the active layer 4 made _{of InAs 0.87} Sb _{0.13 of the} obtained compound semiconductor laminate was evaluated to be 306 arcsec.
The infrared light emitting device of Example 2 was produced by performing the same steps as in Example 1 on this compound semiconductor laminate.

[Example 3]
An infrared light emitting device having the structure shown in FIG. 4 was manufactured as follows.
By the MBE method, a p-type contact layer 6 also serving as a buffer layer, a p-type barrier layer 5, an active layer 4, an n-type barrier layer 3, and n on a substrate 1 made of a semi-insulating GaAs single crystal. By sequentially laminating the mold contact layers 2, a compound semiconductor laminate having a PIN reverse structure was formed.
In this laminating step, 1.0 μm of a p-type GaSb layer doped with ^{3 × 10 18} / cm ^{3 of} Si was formed as the p-type contact layer 6 also serving as a buffer layer. Further, as the p-type barrier layer 5, a p-type Al _0.4 Ga _0.6 ^{Sb layer doped with 3 × 10 18} / cm ^{3 of} Si was formed by 0.02 μm. Further, as the active layer 4, a non-doped InAs _0.87 Sb _0.13 layer was formed in an amount of 2 μm. Further, as the n-type barrier layer 3, an n-type Al _0.3 In _0.7 As _0.87 Sb _0.13 ^{layer doped with Si 7 × 10 18} / cm ³ was formed by 0.02 μm. Further, as the n-type contact layer 2, 0.5 μm of an n-type InAs _0.87 Sb _0.13 ^{layer doped with Si 7 × 10 18} / cm ^{3 was formed.}

In this laminating step, since the vapor pressure is low, it is easy to control, and only Si, which is generally used without toxicity, is used as a dopant. That is, this method is a method excellent in mass productivity as a method for producing a compound semiconductor laminate having a PIN inverse structure.
The full width at half maximum (FWHM value) of the locking curve of the X-ray diffraction peak of the active layer 4 made _{of InAs 0.87} Sb _{0.13 of the} obtained compound semiconductor laminate was evaluated to be 184 arcsec. This value is smaller than the value of the compound semiconductor laminates obtained in Examples 1 and 2. That is, the active layer 4 of the compound semiconductor laminate obtained in Example 3 had better crystallinity than the active layer 4 of the compound semiconductor laminate obtained in Examples 1 and 2.
The reason why this effect was obtained is that in Examples 1 and 2, the buffer layer 7 made of AlGaSb was formed on the substrate 1 with a thickness of 0.5 μm, whereas in Example 3, it also served as a buffer layer. It is presumed that this is because the p-type contact layer 6 made of GaSb is formed with a thickness of 1.0 μm.

The infrared light emitting device of Example 4 was produced by performing the following steps on this compound semiconductor laminate.
First, a step was formed for making contact with the p-type contact layer 6 by wet etching with an acid, an ion milling method, or the like. Next, the compound semiconductor laminate having the steps formed was subjected to mesa etching for element separation. Then, the passivation film 10 made of SiN covered the upper surface of the substrate 1 and the upper surface and the side surface of the element-separated compound semiconductor laminate. Next, a through hole was formed in the electrode-forming portion of the passivation film 10. Next, Au / Ti was vapor-deposited on the stepped portion of the p-type contact layer 6 and on the n-type contact layer 2 by EB (electron beam), and the p-type electrode 9 and the n-type electrode were formed in each through hole by the lift-off method. 8 were formed respectively.
In this way, an infrared light emitting device having the structure shown in FIG. 4 was obtained.

[Example 4]
As the active layer 4, a non-doped InAs _0.91 Sb _0.09 layer was formed in an amount of 2 μm. Further, as the n-type barrier layer 3, an n-type Al _0.3 In _0.7 As _0.91 Sb _0.09 layer 0.02 μm was formed by ^{doping Si with 7 × 10 18} / cm ^3. Further, as the n-type contact layer 2, 0.5 μm of an InAs _0.91 Sb _0.09 ^{layer doped with Si 7 × 10 18} / cm ^{3 was formed.} A compound semiconductor laminate having a PIN inverse structure was formed by the same method as in Example 3 except for this.
The full width at half maximum (FWHM value) of the locking curve of the X-ray diffraction peak was evaluated for the active layer 4 made _{of InAs 0.91} Sb _{0.09 of the} obtained compound semiconductor laminate, and it was 199 arcsec. This value is smaller than the value of the compound semiconductor laminates obtained in Examples 1 and 2. That is, the active layer 4 of the compound semiconductor laminate obtained in Example 4 had better crystallinity than the active layer 4 of the compound semiconductor laminate obtained in Examples 1 and 2.

The reason why this effect was obtained is that in Examples 1 and 2, the buffer layer 7 made of AlGaSb was formed on the substrate 1 with a thickness of 0.5 μm, whereas in Example 4, it also served as a buffer layer. It is presumed that this is because the p-type contact layer 6 made of GaSb is formed with a thickness of 1.0 μm.
The infrared light emitting device of Example 4 was produced by performing the same steps as in Example 3 on this compound semiconductor laminate.

[Example 5]
As the active layer 4, a non-doped InAs _0.96 Sb _0.04 layer of 2 μm was formed. Further, as the n-type barrier layer 3, an Al _0.3 In _0.7 As _0.96 Sb _0.04 ^{layer doped with Si 7 × 10 18} / cm ³ was formed by 0.02 μm. Further, as the n-type contact layer 2, 0.5 μm of an InAs _0.96 Sb _0.04 ^{layer doped with Si 7 × 10 18} / cm ^{3 was formed.} A compound semiconductor laminate having a PIN inverse structure was formed by the same method as in Example 3 except for this.
The full width at half maximum (FWHM value) of the locking curve of the X-ray diffraction peak was evaluated for the active layer 4 composed _{of InAs 0.96} Sb _{0.04 of the} obtained compound semiconductor laminate, and it was 203 arcsec. This value is smaller than the value of the compound semiconductor laminates obtained in Examples 1 and 2. That is, the active layer 4 of the compound semiconductor laminate obtained in Example 5 had better crystallinity than the active layer 4 of the compound semiconductor laminate obtained in Examples 1 and 2.

The reason why this effect was obtained is that in Examples 1 and 2, the buffer layer 7 made of AlGaSb was formed on the substrate 1 with a thickness of 0.5 μm, whereas in Example 5, it also served as a buffer layer. It is presumed that this is because the p-type contact layer 6 made of GaSb is formed with a thickness of 1.0 μm.
By performing the same steps as in Example 3 on this compound semiconductor laminate, an infrared light emitting device of Example 5 was obtained.

[Example 6]
As the active layer 4, a non-doped InAs _0.98 Sb _0.02 layer of 2 μm was formed. Further, as the n-type barrier layer 3, an Al _0.3 In _0.7 As _0.98 Sb _0.02 ^{layer doped with Si 7 × 10 18} / cm ³ was formed by 0.02 μm. Further, as the n-type contact layer 2, 0.5 μm of an InAs _0.98 Sb _0.02 ^{layer doped with Si 7 × 10 18} / cm ^{3 was formed.} A compound semiconductor laminate having a PIN inverse structure was formed by the same method as in Example 3 except for this.
The full width at half maximum (FWHM value) of the locking curve of the X-ray diffraction peak was evaluated for the active layer 4 composed _{of InAs 0.98} Sb _{0.02 of the} obtained compound semiconductor laminate, and it was 248 arcsec. This value is smaller than the value of the compound semiconductor laminates obtained in Examples 1 and 2. That is, the active layer 4 of the compound semiconductor laminate obtained in Example 6 had better crystallinity than the active layer 4 of the compound semiconductor laminate obtained in Examples 1 and 2.

The reason why this effect was obtained is that in Examples 1 and 2, the buffer layer 7 made of AlGaSb was formed on the substrate 1 with a thickness of 0.5 μm, whereas in Example 6, it also served as a buffer layer. It is presumed that this is because the p-type contact layer 6 made of GaSb is formed with a thickness of 1.0 μm.
By performing the same steps as in Example 3 on this compound semiconductor laminate, an infrared light emitting device of Example 6 was obtained.

[Example 7]
As the active layer 4, a non-doped InAs layer of 2 μm was formed. Further, as the n-type barrier layer 3, an Al _0.3 In _0.7 ^{As layer doped with Si 7 × 10 18} / cm ³ was formed in an amount of 0.02 μm. Further, as the n-type contact layer 2, ^{an InAs layer doped with Si 7 × 10 18} / cm ³ was formed in an amount of 0.5 μm. A compound semiconductor laminate having a PIN inverse structure was formed by the same method as in Example 3 except for this.
The full width at half maximum (FWHM value) of the locking curve of the X-ray diffraction peak was evaluated for the active layer 4 made of InAs of the obtained compound semiconductor laminate, and it was 265 arcsec. This value is smaller than the value of the compound semiconductor laminates obtained in Examples 1 and 2. That is, the active layer 4 of the compound semiconductor laminate obtained in Example 7 had better crystallinity than the active layer 4 of the compound semiconductor laminate obtained in Examples 1 and 2.

The reason why this effect was obtained is that in Examples 1 and 2, the buffer layer 7 made of AlGaSb was formed on the substrate 1 with a thickness of 0.5 μm, whereas in Example 7, it also served as a buffer layer. It is presumed that this is because the p-type contact layer 6 made of GaSb is formed with a thickness of 1.0 μm.
By performing the same steps as in Example 3 on this compound semiconductor laminate, an infrared light emitting device of Example 7 was obtained.

Table 1 shows the configurations of each layer other than the substrate of the infrared light emitting element of Examples 1 and 2 and the FWHM value of the obtained active layer. The FWHM values of the active layers obtained are summarized in Table 2.

1 Substrate 2 n-type contact layer 3 n-type barrier layer 4 Active layer 5 p-type barrier layer 6 p-type contact layer 7 Buffer layer 8 n-type electrode 9 p-type electrode 10 Passivation film

Claims (10)

With the board
The n-type contact layer formed on the substrate and
An n-type barrier layer composed of a compound semiconductor layer containing AlInAsSb as a main component and formed on the n-type contact layer, and an n-type barrier layer.
An active layer composed of a compound semiconductor layer containing InAs _x Sb _(1-x) (0 ≦ x ≦ 1) as a main component and formed on the n-type barrier layer, and an active layer.
A p-type barrier layer composed of a compound semiconductor layer containing AlGaSb as a main component and formed on the active layer, and a p-type barrier layer.
The p-type contact layer formed on the p-type barrier layer and
An n-type electrode electrically connected to the n-type contact layer and
A p-type electrode electrically connected to the p-type contact layer and
Equipped with a,
N-type dopant, wherein the n-type contact layer comprises, n-type dopant the n-type barrier layer comprises, and the p-type p-type dopant barrier layer comprises the same der Ru infrared light emitting element. The infrared light emitting device according to claim 1, wherein the n-type dopant contained in the n-type contact layer, the n-type dopant contained in the n-type barrier layer, and the p-type dopant contained in the p-type barrier layer are Si. The substrate is a GaAs substrate
The infrared light emitting device according to claim 1 or 2, further comprising a buffer layer formed between the substrate and the n-type contact layer, which is composed of a compound semiconductor layer containing AlGaSb as a main component. The p-type contact layer, an infrared light emitting device according to any one of claims 1 to 3 comprising a compound semiconductor layer mainly composed of GaSb or GaInSb. The infrared light emitting device according to claim 4, wherein the p-type dopant contained in the p-type contact layer is Si. With the board
The p-type contact layer formed on the substrate and
A p-type barrier layer composed of a compound semiconductor layer containing AlGaSb as a main component and formed on the p-type contact layer, and a p-type barrier layer.
An active layer composed of a compound semiconductor layer containing InAs _x Sb _(1-x) (0 ≦ x ≦ 1) as a main component and formed on the p-type barrier layer, and an active layer.
An n-type barrier layer composed of a compound semiconductor layer containing AlInAsSb as a main component and formed on the active layer, and an n-type barrier layer.
The n-type contact layer formed on the n-type barrier layer and
A p-type electrode electrically connected to the p-type contact layer and
An n-type electrode electrically connected to the n-type contact layer and
Equipped with a,
P-type dopant, wherein the p-type contact layer comprises, p-type dopant, and the n-type barrier layer n-type dopant included in the p-type barrier layer contains the same der Ru infrared light emitting element. The infrared light emitting element according to claim 6, wherein the p-type dopant contained in the p-type contact layer, the p-type dopant contained in the p-type barrier layer, and the n-type dopant contained in the n-type barrier layer are Si. The substrate is a GaAs substrate
The infrared light emitting device according to claim 6 or 7, wherein the p-type contact layer is made of a compound semiconductor layer containing GaSb as a main component. The n-type contact layer, an infrared light emitting device according to any one of claims 8 claims 6 made of a compound semiconductor layer mainly composed of InAsSb. The infrared light emitting device according to claim 9, wherein the n-type dopant contained in the n-type contact layer is Si.

Images