JP3408351B2 - Group III-V compound semiconductor doped with nitrogen impurity and method for manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to III-V doped with nitrogen impurities, which has a high electro-optical conversion efficiency and is suitable for producing a light emitting device having various emission wavelengths and a device using excitons. A group compound semiconductor and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a light emitting device such as a laser diode or a light emitting diode, increasing the efficiency of conversion of electricity from light energy is one of the important themes of research on semiconductor devices. In order to fabricate a highly efficient optical device, it is necessary to confine light and current, and the double hetero structure is widely adopted. Furthermore, in order to manufacture a light emitting device with higher efficiency, the emission intensity is strong,
Photoluminescence (PL) structure with narrow energy distribution,
Or it is necessary to develop materials. Similar properties are required for exciton devices that use excitons. The structure in which the GaP compound semiconductor is doped with nitrogen impurities has a VPE (vapor phase growth ...
It is manufactured using the Vapor Phase Epitaxy method. This nitrogen impurity acts as an isoelectron trap (capture center without charge) in GaP, and a large number of PL light emission with a narrow energy distribution has been observed [DG Thomas, JJ Hopfield,
and CJ Frosch, Phys. Rev. Lett. 15 (1965) p.857]. These luminescence are caused by excitons being trapped by nitrogen impurity pairs existing in the crystal. The trapping energy of this exciton depends on the distance between two nitrogen impurities forming a nitrogen impurity pair. The shorter the distance between the nitrogen impurities forming the pair, the higher the trapping energy. In the conventional method, the nitrogen impurities are doped at the same time as the growth without stopping the growth. Therefore, the nitrogen impurities are uniformly contained in GaP. In the case where the nitrogen impurities are uniformly doped in this way, even if the concentration of the nitrogen impurities is changed, the total P
Only the L intensity changes, and among the many PL emissions,
Only one of them cannot be selectively increased. The PL light emission characteristic with a narrow energy distribution obtained by GaP is utilized in the GaP light emitting diode. However, there are no reports that increase the emission intensity or control the emission wavelength by combining a layer in which Ga atoms are doped with a nitrogen atom and a layer in which GaP is not doped. Further, the double hetero structure using GaP as a quantum well has not been manufactured. This is because there is no suitable III-V group compound semiconductor having a band gap larger than that of GaP. Furthermore, since the GaP film is an indirect semiconductor, it is extremely difficult to manufacture a laser diode. In addition, PL luminescence with a narrow energy distribution has been observed by directly doping GaAs, which is a semiconductor, with nitrogen impurities [R. Schwabe, W. Seifert, F.
Bugge, R.Bindemann, VF Agekyan and SV Pogarev, Soli
d State Commun. 55 (1985) p.167]. In addition, there is a report example in which PL emission was measured by forming about one GaN layer in GaAs [M. Sato, Extended Abstracts of the 1994.
International Conference on solid State Devices an
d Materials, Yokohama (1994) p.7]. In this report,
Since the surface density of nitrogen atoms is as high as 1 × 10 ¹⁴ / cm ² or more, a GaN layer is formed and PL emission due to excitons having a narrow energy distribution is not observed. Rather than the formation of exciton traps by nitrogen impurity pairs, nitrogen atoms are used as host atoms. In addition, the growth of Ga
There is a method (atomic layer doping method) of performing doping by supplying impurities such as Si on the As surface. In this case, a high carrier concentration can be obtained by increasing the supply time and the impurity doping amount.
However, Si, which is an n-type impurity, becomes inactive when paired [S.Sasa, S.Muto, K.Kondo, H.Ishi.
kawa and S. Hiyamizu, Jpn.J.Appl.Phys, 24 (1985) L60
2]. Therefore, the formation of Si pairs by interrupting the growth is not preferable. It is considered that it is not necessary to lengthen the supply time to increase the doping amount, and conversely, if the supply time is lengthened, a pair of Si impurities is formed and the carrier concentration decreases. In addition, a doping superlattice has been produced in which p-type and n-type atomic layer doping is alternately performed. In this superlattice, the PL emission wavelength can be controlled by adjusting the doping amount. However, it is not possible to obtain light emission with a narrow energy distribution with this doping superlattice. In addition, there is a problem that the emission wavelength changes during operation because the internal electric field strength changes due to the excitation intensity [EF Schubert, YH
orikoshi and K. Ploog, Phys. Rev. B (1985) p.1085].
Therefore, the doped superlattice is not used as a light emitting device. Further, by using the inclined substrate, the doping efficiency of p-type or n-type impurities can be increased. In this case, the decomposition efficiency of the source gas is increased or the re-evaporation of impurities is suppressed (M.Kondo, C. Anayama, T. Tanahashi and S. Yamazaki, JC.
ryst.Growth 124 (1992) p.449]. In this case, the concentration of impurities taken in increases. As will be described later, in the present invention, the concentration of the nitrogen impurity that is a doped isoelectron trap does not change even if the inclined substrate is used. Further, the laser diode is directly connected to semiconductors such as GaAs and In.
GaAs or the like is used. In order to reduce the threshold current, semiconductors having a small band gap such as GaAs and InGaAs are replaced with AlGaAs, InAlAs and I.
A double hetero structure sandwiched between semiconductors having a large band gap such as nP is used. This structure is characterized by strong photoluminescence emission. However, it is considered that the further reduction of the threshold current is prevented because the energy distribution of the PL emission has a spread.

[0003]

As described above, in the development of a device using a light-emitting element having good characteristics and an exciton, wavelength controllability and strong emission intensity are required.
It is necessary to develop a compound semiconductor having a structure having PL emission with a narrow energy distribution.

The object of the present invention is to solve the above-mentioned various problems in the prior art, to produce a device using a light emitting element and excitons having high electric-optical conversion efficiency and various emission wavelengths. It is an object of the present invention to provide a III-V group compound semiconductor doped with nitrogen impurities having a preferable structure and a method for manufacturing the same.

[0005]

In order to achieve the above-mentioned object of the present invention, the present invention has a constitution as set forth in the claims. That is, according to the present invention, as described in claim 1, the first III-type doped with nitrogen impurities is used.
The semiconductor device includes a group V compound semiconductor layer and a second group III-V compound semiconductor layer having the same composition as that of the first semiconductor layer and not doped with nitrogen impurities.
The II-V group compound semiconductor layer is sandwiched between the second III-V group compound semiconductor layers, and the first III-V group is formed.
The compound semiconductor layer is a III-V group compound semiconductor doped with nitrogen impurities having a thickness of 20 nm or less . Further, according to the present invention, as described in claim 2, the first III-V group compound semiconductor layer doped with a nitrogen impurity, the semiconductor having the same composition as the first semiconductor layer, and the nitrogen impurity doped. A second III-V compound semiconductor layer which is not formed, and has a structure in which the first III-V compound semiconductor layer and the second III-V compound semiconductor layer are alternately laminated . Half of the first III-V group compound
A III-V group compound semiconductor doped with nitrogen impurities having a conductor layer thickness of 20 nm or less is used. According to a third aspect of the present invention, the first III-V group compound semiconductor layer doped with a nitrogen impurity and the semiconductor having the same composition as the first semiconductor layer are doped with the nitrogen impurity. A second III-V group compound semiconductor layer which is not formed, and the first III-V group compound semiconductor layer is sandwiched by the second III-V group compound semiconductor layer, The third III-V compound semiconductor layer has a band gap larger than that of the third III-V compound semiconductor layer, and the first III-V compound semiconductor layer is formed.
Is a group III-V compound semiconductor doped with a nitrogen impurity having a thickness of 20 nm or less . Further, according to the present invention, as described in claim 4, the nitrogen impurity according to any one of claims 1 to 3 is doped.
In the III-V compound semiconductor, the surface density of nitrogen impurities in the first III-V compound semiconductor layer is set to 1 × 10 ^13.
/ Cm ² or less. Further, according to the present invention, as described in claim 5 , a first step of growing a second III-V group compound semiconductor layer not doped with nitrogen impurities on a substrate, and the second III-V method. A second step of interrupting the growth of the group III compound semiconductor layer and supplying nitrogen impurities to the surface of the second III-V compound semiconductor layer, and doping the nitrogen impurities again after the completion of the second step. The third step of growing a second III-V group compound semiconductor layer which has not been performed III containing at least a nitrogen impurity
A method for manufacturing a group-V compound semiconductor. Further, as described in claim 6 of the present invention, in claim 5 , the fourth step in which neither growth nor addition of nitrogen impurities is performed for a predetermined time between the second step and the third step. A method of manufacturing a III-V group compound semiconductor doped with nitrogen impurities, including steps.

[0006]

Operation III-V doped with nitrogen impurities according to the present invention
The structure of group III compound semiconductors is such that a thin layer doped with nitrogen atoms, which is an isoelectron trap, is sandwiched between undoped layers, or a thin layer doped with nitrogen atoms and undoped It is characterized in that the layer is repeatedly included by changing its period or sandwiched between semiconductors having a large band gap. Further, in the method for producing a III-V group compound semiconductor having a structure doped with nitrogen impurities according to the present invention, III-
A step of once interrupting the growth of the group V compound semiconductor and doping with a nitrogen impurity, which is an isoelectron trap, and / or
Alternatively, a step including neither semiconductor growth nor nitrogen impurity doping after nitrogen impurity doping is included, or nitrogen impurity is doped on the tilted substrate.
The main feature is to produce a III-V group compound semiconductor. In the prior art, there is no report that the emission intensity is increased or the emission wavelength is controlled by combining a layer in which GaAs is doped with nitrogen atoms and a layer in which GaAs is not doped. further,
A double hetero structure using GaAs doped with nitrogen impurities as a quantum well has not been manufactured. In addition, there is no example in the prior art in which the growth of a semiconductor is stopped to promote the formation of a nitrogen impurity pair that serves as an emission center. Also,
Although a (001) tilted substrate tilted twice in the [110] direction is used, the effect of the tilted substrate on nitrogen doping has not been clarified. In the III-V group compound semiconductor doped with nitrogen impurities and the method for manufacturing the same according to the present invention, unlike the prior art, the thickness of the layer doped with nitrogen atoms is thin, and the thickness doped with nitrogen atoms which is an isoelectron trap. Thin layer and undoped layer are repeatedly included by changing the period, combined with a layer not doped with nitrogen atoms, sandwiched between semiconductors with a large band gap, and semiconductor growth is stopped. And the like, that is, a nitrogen impurity that is an electron trap is doped, that the formation of a nitrogen impurity pair is promoted by the process of performing neither growth nor doping after performing the nitrogen impurity doping, and that the formation of a nitrogen impurity pair is performed by using a tilted substrate. Points to promote are mentioned. The III-V group compound semiconductor doped with nitrogen impurities of the present invention is
The first III-V group compound semiconductor layer doped with a nitrogen impurity, and the second semiconductor which has the same composition as that of the first semiconductor layer and is not doped with a nitrogen impurity. III-V group compound semiconductor layer, the first III-V group compound semiconductor layer, the second
And the thickness of the first III-V group compound semiconductor layer is
It is set to 20 nm or less . In other words, the structure is such that a thin layer that is doped with nitrogen atoms, which is an isoelectron trap, is sandwiched between undoped layers, so that a layer that is not doped with nitrogen impurities existing around the layer doped with nitrogen impurities is The formed excitons are easily captured by nitrogen impurities. Therefore, good PL emission with high emission intensity and narrow energy distribution can be obtained. Also,
First III-V compound semi-doped with nitrogen impurities
By setting the thickness of the conductor layer to 20 nm or less,
As shown in, good PL intensity is obtained. Also,
The first III-V compound semiconductor layer doped with a nitrogen impurity, and the second semiconductor which has the same composition as that of the first semiconductor layer and is not doped with a nitrogen impurity. III-V group compound semiconductor layer, wherein the first III-V group compound semiconductor layer and the second I-group compound semiconductor layer
A II-V group compound semiconductor layer, for example, is formed into a structure that alternately includes the period thereof by changing, and the first III-V group is formed.
The compound semiconductor layer has a thickness of 20 nm or less . In this case, a nitrogen impurity existing in one doping layer and a nitrogen impurity existing in another doping layer form a pair. Therefore, the distance between the nitrogen impurities forming the pair is controlled by the distance between the two doping layers, so that the emission wavelength can be controlled. In addition, nitrogen impurities
Thickness of the doped first III-V compound semiconductor layer
Is set to 20 nm or less.
As described above, good PL intensity can be obtained. Further, as described in claim 3, the first III-doped with the nitrogen impurity is used.
The semiconductor device includes a group V compound semiconductor layer and a second group III-V compound semiconductor layer having the same composition as that of the first semiconductor layer and not doped with nitrogen impurities.
A structure in which a II-V group compound semiconductor layer is sandwiched between the second III-V group compound semiconductor layers has a band gap larger than that of the first III-V group compound semiconductor layer.
Structure and without sandwiching at V compound semiconductor layer, the first III
The thickness of the -V compound semiconductor layer is 20 nm or less . Therefore, the excitons captured by the nitrogen impurity pair increase, and the PL emission efficiency increases. Furthermore, the emission wavelength can be controlled, and stable excitons are formed even at high temperatures. In addition, the first doped with nitrogen impurities
The thickness of the III-V group compound semiconductor layer is 20 nm or less.
As a result, as shown in FIG.
You get a degree. Further, as described in claim 4, by setting the areal density of the nitrogen impurities of the doped first III-V compound semiconductor layer to 1 × 10 ¹³ / cm ² or less, as shown in FIG. Good PL intensity can be obtained. In addition, for example, a first substrate obtained by doping a substrate with a crystal orientation inclined from the (001) plane by a predetermined angle with a nitrogen impurity.
By stacking the III-V group compound semiconductor layer of (3), the formation of a nitrogen impurity pair due to the nitrogen impurities being taken into the step is promoted, and a light emitting element having many light emission centers can be obtained. Further, for example, as shown in FIG.
The PL intensity can be improved even if the crystal orientation of the substrate is slightly inclined. Further, claim 5 or claim 6
The nitrogen impurity of the present invention was doped as described in 1.
In the method for manufacturing a III-V compound semiconductor, a step of stopping the growth of the III-V compound semiconductor and doping with a nitrogen impurity is used. Therefore, the nitrogen impurities taken into the film move on the growth surface during the growth interruption to promote the formation of nitrogen impurity pairs and form many emission centers. Therefore, light emitting devices having various emission wavelengths can be obtained. Further, for example, nitrogen impurities are doped on the substrate in which the crystal orientation of the substrate is inclined from the (001) plane by a predetermined angle. Therefore, the formation of a nitrogen impurity pair is promoted by incorporating the nitrogen impurity into the step, and a light emitting device having many light emission centers is obtained. As described above, the nitrogen impurity-doped III-V group compound semiconductor of the present invention can improve the electro-optical conversion efficiency in a light emitting device, and can realize an exciton device having excellent characteristics.

[0007]

Embodiments of the present invention will be described below in more detail with reference to the drawings. Example 1 FIG. 1 is a schematic diagram showing an example of a cross-sectional structure of a compound semiconductor obtained by doping GaAs with a nitrogen impurity according to an example of the present invention. A thin GaAs layer 11 doped with nitrogen impurities is sandwiched between GaAs layers 12 not doped with nitrogen impurities. Nitrogen gas was pyrolyzed by a heated W (tungsten) filament and then supplied to a substrate to dope nitrogen impurities. A molecular beam epitaxial (MBE) method was used for growing the GaAs layer. In the present invention, the supply of Ga and As onto the GaAs substrate is stopped, and nitrogen gas is supplied onto the GaAs substrate through the heated W filament to dope the nitrogen impurities. The substrate used is a (001) just cut GaAs substrate. Substrate temperature is 590 ° C, filament temperature is 1200
° C, nitrogen gas flow rate is 0.3 cc / min, supply time is 1
It was set to 0 minutes. In this case, a step on the surface of the GaAs layer 11,
Considering the internal diffusion of nitrogen atoms, the thickness of the GaAs layer 11 doped with nitrogen impurities is considered to be about 1 nm. GaAs layer 1 not doped with nitrogen impurities
The thickness of each of the two is 400 nm. The area density of nitrogen impurities is estimated to be 1.4 × 10 ⁹ / cm ² . It is impossible to measure such a low concentration of nitrogen impurities. Here, high-concentration impurity doping (1 × 10 ¹⁴
/ Cm ² ), SIMS (secondary ion mass spectrometry) measurement was performed on the sample, and the impurity concentration was estimated from the filament temperature dependence of the doping concentration. Therefore, the value of the doping concentration in the low concentration region may include an error of about one digit. FIG. 2 shows a PL emission spectrum at a low temperature (8.4 K) for the structure shown in FIG.
The PL intensity (arbitrary unit) with respect to the wavelength (nm) is shown. For comparison, a PL spectrum in a conventional structure in which GaAs is uniformly doped with nitrogen impurities is also shown. Both use optimized growth conditions so that light emission due to nitrogen impurities is most prominent.
In both cases, light emission from GaAs and residual impurities is observed. In the conventional structure, light emission from a nitrogen impurity is observed near 822 nm, but the intensity is very weak. However, in the structure of the present invention, a large number of sharp peaks are observed more prominently in the energy position smaller than that of the light emission to GaAs as compared with the conventional structure. The full width at half maximum is 1 meV or less, and PL light emission with a narrow energy distribution is obtained. Light emission in the vicinity of 860 nm is extremely weak from the conventional structure. Since this luminescence has the highest trapping energy, it is the luminescence from the excitons trapped by the closest nitrogen impurity pair present in the crystal. The strong emission intensity near 860 nm in this example is because the nitrogen impurities formed a pair on the GaAs surface by supplying the nitrogen impurities during the growth interruption. As described above, in the structure of the example of the present invention, the emission intensity is strong and the energy distribution is narrow, and in the conventional example, strong PL emission is observed at the wavelength position where the intensity is weak.

Example 2 FIG. 3 shows an AlGaAs / GaAs quantum well structure in which the well layer is doped with nitrogen impurities. Thin G with dope-pigmented nitrogen impurities
aAs layer 31 and undoped GaAs layer 3
2 shows a structure in which 2 is sandwiched between AlGaAs layers 33.
The thickness of the GaAs layer 31 doped with nitrogen impurities is 1
The thickness of the undoped GaAs layer 32 is 110 nm. The substrate used is (00
1) Just cut GaAs substrate. FIG. 4 shows FIG.
The wavelength (nm) and PL intensity (arbitrary unit) at low temperature (8.4K) of the AlGaAs / GaAs quantum well structure shown in FIG. The half-value width of the emission peak from an ordinary quantum well without doping is 5 meV, whereas the half-value width of the PL spectrum in the quantum well structure of the present invention is 1 meV or less, and the single energy distribution is narrow, A strong PL light emission is obtained. The peak wavelength is reduced by doping in the quantum well structure (see comparison with the peak of the embodiment of the present invention shown in FIG. 2). In the structure shown in FIG. 1 in which GaAs is doped with nitrogen impurities, light emission due to nitrogen impurities disappears at around 80K. On the other hand, by using the quantum well structure shown in FIG. 2, light emission due to nitrogen impurities was observed even at 120K. This is because the quantum well structure is adopted,
It is thought that this is because excitons are now stably present even at high temperatures. Here, an undoped GaAs layer 32 is inserted in the quantum well. However, AlGaAs not doped with nitrogen impurities
Due to the contribution of the barrier layer of layer 33, it is possible to omit the undoped GaAs layer 32.

<Third Embodiment> FIG. 5 shows a structure including two layers of GaAs doped with nitrogen impurities.
An undoped GaAs layer 53 is sandwiched between thin GaAs layers 51 doped with nitrogen impurities,
Further, it is sandwiched by GaAs layers 52 which are not doped. The substrate used is (001) just cut GaA.
s substrate. The thickness of the GaAs layer 51 doped with nitrogen impurities was fixed to 1 nm, and the thickness of the undoped GaAs layer 53 was changed to prepare two types of samples. One is undoped GaAs
The layer 53 had a thickness of 10 nm, and the other had a thickness of 100 nm. The PL emission spectrum of the structure shown in FIG. 5 at low temperature (8.4K) is shown in FIG. In both cases, the energy distribution related to nitrogen impurities is narrow and the strength of P is strong.
The L spectrum is obtained. However, the shapes of emission spectra are very different. From this, it can be seen that the spectrum shape can be controlled by changing the thickness of the undoped GaAs layer 53. In the embodiment of the present invention, unlike the case of the doping superlattice, the emission wavelength position does not change depending on the incident light intensity. In this embodiment, a nitrogen impurity existing in one doping layer and a nitrogen impurity existing in another doping layer form a pair. Therefore, since the distance between the nitrogen impurity pairs is controlled by the distance between the two doping layers, the emission wavelength can be controlled. Although two doping layers are used here, the same effect can be obtained with two or more layers. Further, it has been confirmed that the same result as above can be obtained even if several AlGaAs / GaAs quantum well structures in which the well layers are doped with nitrogen impurities are combined.

<Embodiment 4> In the structure shown in FIG.
GaA by changing the heating temperature of the filament
The areal density of the s layer 11 was changed. The substrate used is (00
1) Just cut GaAs substrate. FIG. 7 shows the relationship between the areal density (cm ⁻² ) of doping and the PL intensity (photon count number) of the peak near 860 nm at low temperature (8.4 K). Nitrogen impurity concentration is 1 × 10 ¹³
If it exceeds / cm ² , PL emission observed near 860 nm cannot be obtained.

Example 5 The layer structure shown in FIG. 1 was formed on a substrate (called an inclined substrate) whose crystal orientation was inclined from the (001) plane. FIG. 8 shows the relationship between the tilt angle (degree) and the PL intensity (photon count number) at a low temperature (8.4 K) with a peak near 860 nm. The substrate was tilted in the [110] direction. First, nitrogen impurities were supplied on the GaAs surface where the growth was stopped for 1 minute. The nitrogen impurity concentration is 1 × 10 ⁹ / cm ² . The other growth conditions are the same as in Example 1, and only the substrate tilt angle is changed. S for heavily doped samples
In the IMS measurement, the concentration of nitrogen impurities taken in is constant even if the tilt angle is different, and therefore it is considered that the surface density of nitrogen impurities is also constant in this example. As shown in FIG. 8, the PL emission intensity was increased by using the tilted substrate, even though the amount of nitrogen impurities taken in was the same. It is considered that this is because the formation of the nitrogen impurity pair was promoted by using the inclined substrate. It is considered that the emission intensity for the GaAs substrate having the inclination angle of 0 (zero) is lower than the emission intensity shown in FIG. 7 because the nitrogen impurity supply time is short. Considering that nitrogen impurities are taken into the step of the tilted substrate to form a pair, the tilt direction may not be the [110] direction. Furthermore, the substrate surface tilted by 10 degrees is (711)
Since it corresponds to the plane, it has been confirmed that the same effect can be obtained even with a substrate that is largely inclined from the (100) plane, such as the (111) plane.

Example 6 FIG. 9 shows the growth interruption time (m
in) and the PL intensity (photon count number) of the peak near 860 nm at low temperature (8.4 K). The substrate used is (001) just cut Ga
It is an As substrate. First, nitrogen impurities were supplied for 1 minute on the GaAs surface where the growth was interrupted. Nitrogen impurity concentration is 1
It was × 10 ⁹ / cm ² . After that, the time until the start of growth was defined as the growth interruption time. The emission intensity increases with the growth stop time and tends to be saturated. It is considered that, while the growth was stopped, individual nitrogen impurities moved on the GaAs surface to form a pair, so that the PL emission peak intensity near 860 nm became stronger. further,
It has been confirmed that even when a growth method other than MBE is used, the same effect can be obtained by interrupting the growth and doping with nitrogen atoms.

Example 7 In the structure shown in FIG. 1, PL emission intensity was examined when the thickness of the nitrogen impurity doping layer was changed. FIG. 10 shows the thickness (nm) of the nitrogen impurity doping layer and 860 nm at a low temperature (8.4K).
The relationship with the peak PL emission intensity (normalized PL intensity) in the vicinity is shown. The substrate used is (001) just cut G
It is an aAs substrate. Sheet concentration of doping layer is 1 ×
It was fixed at 10 ⁹ / cm ² . The emission intensity decreases as the thickness of the doping layer increases. The thickness of the doping layer is 20n
Since the emission intensity is 1/10 or less when m or more, the thickness of the doping layer is preferably 20 nm or less. In the above-described embodiments of the present invention, an example in which GaAs is doped with nitrogen impurities is shown.
II such as nGaAs, GaP, GaAsP, AlGaAs
It has been confirmed that it is also applicable to IV compound semiconductors.

[0014]

As described in detail above, the III-V compound semiconductor having the layer structure doped with nitrogen impurities of the present invention is doped with nitrogen impurities existing around the layer doped with nitrogen impurities. The excitons formed in the non-existing layer are captured by the nitrogen impurities, so that the PL emission with high emission intensity and narrow energy distribution can be obtained.
Further, by sandwiching the semiconductor with a large band gap, the emission intensity increases, and a stable and sharp PL emission peak can be obtained even at high temperature. Further, the emission wavelength can be controlled without depending on the photoexcitation intensity by changing the stacking period of the layer with a thin layer of nitrogen atoms and the layer without doping. Further, while the growth of the semiconductor is stopped, individual nitrogen impurities can move on the GaAs surface to form a pair, and the emission intensity becomes strong. Further, by using the inclined substrate, the nitrogen impurities easily form a pair, so that a compound semiconductor having a layer structure with high emission intensity can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing a structure of a compound semiconductor in which a GaAs layer illustrated in Example 1 of the present invention is doped with nitrogen impurities.

FIG. 2 is the P of the compound semiconductor illustrated in Example 1 of the present invention.
The figure which showed L emission spectrum compared with the prior art example.

FIG. 3 is a schematic diagram showing the structure of a compound semiconductor having an AlGaAs / GaAs quantum well structure doped with nitrogen impurities, which is illustrated in Example 2 of the present invention.

FIG. 4 is the P of the compound semiconductor illustrated in Example 2 of the present invention.
The figure which shows L emission spectrum.

FIG. 5 is a schematic diagram showing the structure of a compound semiconductor having two layers doped with nitrogen impurities as exemplified in Example 3 of the present invention.

FIG. 6 is the P of the compound semiconductor exemplified in Example 3 of the present invention.
The figure which shows L emission spectrum.

FIG. 7 is a diagram showing the relationship between the doping concentration and the PL emission intensity of the peak around 860 nm, which is illustrated in Example 4 of the present invention.

FIG. 8 is a tilt angle of the substrate illustrated in Example 5 of the present invention and 8;
The figure which shows the relationship with PL emission intensity of the peak of 60 nm vicinity.

FIG. 9: Growth interruption time and 8 exemplified in Example 6 of the present invention
The figure which shows the relationship of PL emission intensity of the peak of 60 nm vicinity.

FIG. 10 is a diagram showing the relationship between the layer thickness of the nitrogen impurity doping layer and the PL emission intensity of the peak around 860 nm, which is illustrated in Example 7 of the present invention.

[Explanation of symbols]

11 ... Thin GaAs doped with nitrogen impurities
Layer 12 ... GaAs layer not doped with nitrogen impurities 31 layer ... GaAs thinly doped with nitrogen impurities
Layer 32 ... Undoped GaAs layer 33 ... AlGaAs layer 51 ... Nitrogen-doped thin GaAs
Layer 52 ... GaAs layer not doped 53 ... GaAs layer not doped

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 59-9984 (JP, A) JP 6-283760 (JP, A) JP 6-53602 (JP, A) JP 5- 291617 (JP, A) JP 54-74686 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01S 5/00-5/50 H01L 21/203 H01L 33/00 JISST File (JOIS)

Claims (6)

(57) [Claims] 1. A first III-doped with a nitrogen impurity.
The semiconductor device includes a group V compound semiconductor layer and a second group III-V compound semiconductor layer having the same composition as that of the first semiconductor layer and not doped with nitrogen impurities.
The II-V group compound semiconductor layer is sandwiched between the second III-V group compound semiconductor layers, and the first III-V group is formed.
A III-V group compound semiconductor doped with nitrogen impurities, wherein the compound semiconductor layer has a thickness of 20 nm or less . 2. A first III-doped with a nitrogen impurity.
The semiconductor device includes a group V compound semiconductor layer and a second group III-V compound semiconductor layer having the same composition as that of the first semiconductor layer and not doped with nitrogen impurities.
A structure in which a II-V group compound semiconductor layer and the second III-V group compound semiconductor layer are alternately laminated, and the first II
I-V group compound semiconductor Group III-V doped with nitrogen impurities, wherein the this <br/> to a thickness of 20nm or less of layer compound semiconductor. 3. A first III-doped with a nitrogen impurity.
The semiconductor device includes a group V compound semiconductor layer and a second group III-V compound semiconductor layer having the same composition as that of the first semiconductor layer and not doped with nitrogen impurities.
A structure in which a II-V group compound semiconductor layer is sandwiched between the second III-V group compound semiconductor layers has a band gap larger than that of the first III-V group compound semiconductor layer.
The structure is sandwiched between the group V compound semiconductor layers, and the first II
I-V group compound semiconductor Group III-V doped with nitrogen impurities, wherein the this <br/> to a thickness of 20nm or less of layer compound semiconductor. 4. The nitrogen impurity-doped III-V compound semiconductor according to claim 1, wherein a nitrogen impurity has an area density in a first III-V compound semiconductor layer. be between 1 × ¹⁰ 13 / cm ² or less
That was doped with nitrogen impurities, characterized in that the III-
Group V compound semiconductor. 5. A first step of growing a second III-V compound semiconductor layer not doped with nitrogen impurities on a substrate, and interrupting the growth of the second III-V compound semiconductor layer. ,
A second step of supplying nitrogen impurities to the surface of the second III-V compound semiconductor layer, and a second III-V group not doped with nitrogen impurities again after the completion of the second step. A method for manufacturing a III-V group compound semiconductor doped with a nitrogen impurity, comprising at least a third step of growing a compound semiconductor layer. 6. The method according to claim 5 , further comprising a fourth step between the second step and the third step in which neither growth nor addition of nitrogen impurities is performed for a predetermined time. A method for manufacturing a III-V group compound semiconductor doped with nitrogen impurities.