WO2013157881A1 - Semiconductor device and method for manufacturing same - Google Patents

Abstract

A semiconductor device and a method for manufacturing the same are disclosed. A method for manufacturing a p-type nitride-based semiconductor layer of the semiconductor device comprises forming a AlxGa1-xN semiconductor layer (0 ＜ x <= 1) by repeating the steps of: supplying a source of periodic group III for a predetermined time T1, supplying a source of periodic group V that contains a carbon source material for a predetermined time T2 when a predetermined time t1 elapses after starting to supply the source of periodic group III, and supplying the source gas of periodic group III when a predetermined time t2 elapses after starting to supply the source of periodic group V; and supplying the source of periodic group V.

Description

Semiconductor device and method of manufacturing same

The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a method of manufacturing a carbon-doped nitride-based semiconductor layer, and a p-type nitride-based semiconductor layer manufactured using the same and a device using the same.

Controlling the electrical conductivity of p-type AlGaN is a very difficult problem from a scientific and technical point of view. Magnesium (Mg) is the main p-type dopant for GaN and AlGaN. However, the energy level of Mg as an acceptor is about 230 meV (experimental value) in GaN, which is larger and deeper in AlGaN, which is deeper than that of AlGaN. As a result, the hole concentration of Mg-doped AlGaN is extremely low compared to the hole concentration of Mg-doped GaN.

Therefore, since Mg-doped AlGaN has very low electrical conductivity, the use of Mg as a p-type dopant is not suitable for light emitting devices such as light emitting diodes (LEDs) and laser diodes using AlGaN having a high aluminum composition. This was very difficult. In addition, GaN or AlGaN-based nitride semiconductors, such as those used for ultra-high frequency or power control, have the same problem.

For example, the energy level of Mg deepens with increasing aluminum composition ratio in AlGaN. Therefore, the activation ratio of the holes constrained to Mg becomes 1% or less, the AlGaN hole concentration becomes very low, and the electrical resistance of the AlGaN layer becomes high. For this reason, when a large amount of Mg is added so that the added amount is about 2 × 10 ²⁰ cm ^-3 or more, segregation of Mg occurs and crystal quality is very poor. Therefore, it is no longer possible to add more Mg than the added amount. Therefore, it has been difficult to realize an LED, a power control electronic device, or a semiconductor laser using Mg-doped AlGaN.

In addition, since the hole concentration of the current Mg-doped AlGaN semiconductor layer is low, the resistance is large, and the thickness of the p-type AlGaN layer in the current LED structure is limited to 0.1 µm to 0.2 µm. In addition, an ultraviolet region semiconductor laser using an AlGaN semiconductor layer having a high Al content has not yet been realized, and there is a limitation that the oscillation wavelength of the semiconductor laser is limited to the long wavelength side close to the forbidden band of GaN.

In addition, Mg has a great thermal diffusion, and in the case of producing an n-type layer on a p-type layer to which Mg is added, Mg thermally diffuses along a defect to realize an n-type layer. Therefore, npn or pnp bipolar transistors were not feasible. Therefore, it has become a big obstacle in realizing the control power supply device of an electric vehicle and a hybrid vehicle.

As described above, since there are various problems with the p-type layer doped with Mg, Japanese Patent Application Laid-Open No. 2011-023541 discloses more than 40 degrees with respect to a reference plane orthogonal to a reference axis extending in the c-axis direction. P-type gallium nitride-based semiconductor layer having a carbon concentration of not less than Mg but also a carbon concentration of 2 × 10 ¹⁶ cm ⁻³ or more on the main surface of the support using a support made of a group III nitride semiconductor having an angle of 140 degrees or less A technique is disclosed.

(Prior art document)

Japanese Patent Application Laid-Open No. 2011-023541

Since carbon is a positive impurity, it may be either an acceptor or a donor depending on the substance into which carbon is introduced. In the method for producing the Mg and carbon doped p-type gallium nitride semiconductor layer disclosed in Patent Document 1, the p-type formation could not be sufficiently stabilized even when the gallium nitride-based semiconductor layer was n-type. That is, since the main surface of the support made of group III-V nitride-based semiconductor has an angle of 40 degrees to 140 degrees with respect to the reference plane orthogonal to the reference axis extending from the c-axis direction, carbon is stabilized and functions as a p-type impurity. Did not do it. In addition, other experimental and theoretical discussions conducted on the (1-101) plane of carbon-doped hexagonal GaN and other surfaces of GaN did not achieve sufficient p-type conductivity.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of such circumstances, and an object of the present invention is to provide a method of manufacturing a semiconductor device including a carbon-doped p-type gallium nitride based semiconductor layer having high reproducibility and improved productivity.

In addition, another object of the present invention is to provide a p-type gallium nitride-based semiconductor layer having a high electrical conductivity and low resistance, and a semiconductor light emitting device including the same.

In the method of manufacturing a p-type nitride semiconductor layer according to an embodiment of the present invention, a carbon source material is supplied after supplying a group III source for a predetermined time T ₁ , and after a predetermined time t ₁ has elapsed after the start of supplying the group III source. A Group V source containing the same is supplied for a predetermined time T ₂ (wherein t ₁ + T ₂ > T ₁ ), and after starting the Group V source supply, the predetermined time t ₂ (wherein t ₁ + T ₂ -t ₂ > T ₁ ), the step of supplying the Group III source gas and the step of supplying the Group V source is repeated, the growth temperature of 1190 ℃ to 1370 ℃ using chemical vapor deposition or vacuum deposition method or at a growth temperature that the substrate temperature is _{1070 ℃ ~ 1250 ℃, Al x} Ga 1 - includes forming _x N semiconductor layer (0 <x ≤ 1), and doping the carbon to the nitrogen site of the semiconductor layer.

The single crystal substrate may have an offset angle in the main plane of ± 0.1% with respect to the (0001) C plane.

The carbon source material may be carbon tetrabromide (CBr ₄ ).

The group V source may comprise a magnesium source material.

The aluminum content may be 5 mol% to 100 mol%.

Further, it may not set the overlap between the supply time T ₂ of the supply time of the group III source and T ₁ wherein the group V source gas, the supply time of said Group III wherein the Group V and the supply time T ₁ of the source Source T distance between the _two can be up to more than 2 seconds 0 seconds.

In a III-V nitride-based semiconductor layer growth method for growing a III-V nitride-based semiconductor layer by using a MOVPE method directly on a substrate or through a single or a plurality of intervening layers, another embodiment of the present invention The growth method of the III-V nitride-based semiconductor layer according to the present invention includes a group III atomic source gas of Al _x Ga _1-x N (0 <x ≤ 1), a group V atomic source gas, and a p-type impurity in a reaction tube. And alternately growing an atomic layer of group III atoms and an atomic layer of carbon doped Group V atoms, the substrate being sapphire substrate, silicon substrate, silicon carbide substrate, gallium nitride substrate, nitride It is composed of any one of aluminum substrates, and the main surface has an offset angle in the range of ± 0.1% with respect to the C surface and the equivalent crystal surface.

Another embodiment of the present invention provides a method for growing a group III-V nitride semiconductor layer, wherein the group III-V nitride semiconductor layer is grown on the substrate directly or through a single layer or a plurality of intervening layers by using the MOVPE method. In the growth method of the III-V nitride-based semiconductor layer according to the example, a Group III atom source gas of Al _x Ga _1-x N (0 <x ≤ 1) is supplied into the reaction tube for a predetermined time, and then Group V atoms Alternately growing the group III atomic layer and the group V atomic atomic layer by alternately supplying the source gas for a predetermined time, and supplying the group V atomic source gas as a p-type impurity Carbon is also introduced into the atomic layer of the group V atoms by supplying a carbon source gas together.

The growth method may further include supplying an Mg source gas while supplying the group V atomic source gas for the predetermined time.

The growth method may further include supplying Mg source gas during the process of supplying the Group III atomic source gas of Al _x Ga _{1- x} N for a predetermined time and then supplying the Group V atomic source gas for a predetermined time. It may further include.

The growth method may further include supplying a source gas of Mg while supplying the group V atomic source gas for the predetermined time.

The substrate may be composed of any one of a sapphire substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and an aluminum nitride substrate.

The main surface of the substrate may have an offset angle in the range of ± 0.1% with respect to the C surface and the equivalent crystal surface.

The III-V nitride-based semiconductor layer may have a thickness of 0.1 μm or more and 3 μm or less.

Group III-V nitride and semiconductor layers of Al x Ga 1-x N are simultaneously supplied into the reaction tube to grow a group III-V nitride semiconductor layer directly on the substrate or through one or more intervening layers. A method of growing a group nitride semiconductor layer, the method of growing a group III-V nitride semiconductor layer according to another embodiment of the present invention includes supplying a carbon source gas as a p-type impurity, The ratio of the atomic source gas and the group III atomic source gas may be 5 or more and 600 or less.

The substrate may include any one of a sapphire substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and an aluminum nitride substrate, and the main surface may have an offset angle in the range of ± 0.1% with respect to the C surface and an equivalent crystal surface.

According to another embodiment of the present invention, a nitride semiconductor light emitting device includes an n-type nitride semiconductor layer, an active layer, and a p-type nitride semiconductor layer, wherein the p-type nitride semiconductor layer is a sapphire substrate or a silicon substrate. , A silicon carbide substrate, a gallium nitride substrate, or an aluminum nitride substrate, the main surface being directly on the substrate having an offset angle in the range of ± 0.1% with respect to the C surface and its equivalent crystal surface, or a singular or plural intervening layer By supplying a group III atomic source gas of Al _x Ga _{1 - x} N (0 <x ≤ 1), a group V atomic source gas, and a carbon source gas as a p-type impurity, the atomic layer and carbon of the group III atom The atomic layers of the doped group V atoms were alternately grown.

A nitride semiconductor light emitting device according to another embodiment of the present invention includes a stack of an n-type nitride-based semiconductor layer, an active layer and a p-type nitride-based semiconductor layer, wherein the p-type nitride-based semiconductor layer is III in the reaction tube A group formed by alternately growing an atomic layer of group III atoms and an atomic layer of group V atoms by supplying group atom source gas and group V atom source gas alternately for a predetermined time, and supplying the group V atom source gas Carbon was also introduced by supplying a carbon source gas to the reactor.

The p-type nitride semiconductor layer may be Al _x Ga _{1 - x} N (0 <x ≦ 1).

The nitride-based semiconductor light emitting device may further include a p-type electrode formed on the p-type nitride-based semiconductor layer.

In a semiconductor laser according to another embodiment of the present invention, in which the p-type nitride semiconductor layer is grown on the substrate directly or through one or a plurality of intervening layers, the III-V nitride semiconductor layer is grown using MOVPE. In the -V nitride-based semiconductor layer growth method, a step of supplying a Group III atomic source gas of Al _x Ga _1-x N into the reaction tube for a predetermined time, and then alternately supplying a Group V atomic source gas for a predetermined time To alternately grow an atomic layer of group III atoms and an atomic layer of group V atoms, and supply the group V atomic source gas with a carbon source gas as a p-type impurity while supplying the group V atomic source gas for a predetermined time. And a group III-V nitride semiconductor layer into which carbon is introduced.

The layer thickness of the p-type nitride-based semiconductor layer may be 3㎛.

According to the present invention, since the p-type nitride semiconductor layer produced by the method for producing a p-type nitride semiconductor layer according to the present invention is doped with carbon stably, the present invention provides a carbon-doped p-type with improved productivity. A method for producing a p-type nitride semiconductor layer such as AlGaN can be provided.

In addition, a carbon-doped p-type III-V compound semiconductor can be realized with Al x Ga 1-x N (0.001? X? 1), the composition of Al can be increased by 77%, and a p-type nitride compound semiconductor layer having a wide band gap is provided. Can be generated.

In addition, since a p-type III-V compound semiconductor layer having low resistance can be realized even in a power supply device having a large current, a higher performance nitride-based power control device can be realized.

1 is a process diagram schematically illustrating a crystal growth step of a p-type AlGaN semiconductor layer on a single crystal substrate according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a supply timing of growth elements before and after growth of a p-type AlGaN semiconductor layer in crystal growth of a p-type AlGaN semiconductor layer on a single crystal substrate according to an embodiment of the present invention.

(A) of FIG. 3 is a low temperature emission (PL) spectrum obtained from an undoped AlGaN having an Al composition ratio of 8%, and (b) is a low temperature emission (PL) spectrum obtained from a C-doped AlGaN having an Al composition ratio of 9%.

4 (a) and (b) are graphs showing the dependence of free electron density on the flow rate of CBr ₄ for carbon doped Al _0.1 Ga _0.9 N.

5A and 5B are graphs showing a depth profile of NIAD of C-doped AlGaN having an Al composition ratio of 55%, (a) relates to an AlGaN semiconductor layer doped with C and Mg simultaneously, and (b) ) Is for the C-doped AlGaN semiconductor layer.

FIG. 6A illustrates carbon doping characteristics of AlGaN having an Al composition ratio of 10%, and FIG. 6B illustrates carbon doping characteristics of AlGaN having an Al composition ratio of 55%.

7A and 7B show Mg-doped GaN (layer thickness 0.08 μm) / C-doped AlGaN (layer thickness 0.1 μm) / undoped GaN (layer thickness 10 nm) / Si-doped AlGaN (3 to 4 μm) Is a SIMS analysis of an LED sample having a double heterostructure.

8 is a graph showing the dependence of the carbon acceptor electrical activation ratio on the Al composition ratio.

9 is a graph evaluating the activation energy of the carbon acceptor of Al _0.27 Ga _0.73 N and the Mg acceptor of GaN using the experimental electrical activation ratio of carbon and magnesium acceptors at room temperature.

FIG. 10 is a first example of one cycle of the gas supply method in the case of epitaxially growing Al _x Ga _1-x N by an alternate supply method according to another embodiment of the present invention.

FIG. 11 is a second example of one cycle of the gas supply method in the case of epitaxially growing Al _x Ga _1-x N by an alternate supply method according to another embodiment of the present invention.

12 is a third example of one cycle of the gas supply method in the case of epitaxially growing Al _x Ga _1-x N by an alternate supply method according to another embodiment of the present invention.

FIG. 13 shows the hole concentration in the AlGaN semiconductor film depth direction by CV measurement (ionization impurity concentration measurement) of a film in which an Al _x Ga _1-x N semiconductor (x = 0.55) was grown by the source gas supply method of the first example. .

Fig. 14 shows the hole concentration in the AlGaN semiconductor film depth direction by CV measurement (ionization impurity concentration measurement) of a film in which an Al _x Ga _1-x N semiconductor (x = 0.55) was grown by the method of supplying the source gas of the second example. .

15 is a fourth example of one cycle of the gas supply method in the case of epitaxially growing Al _x Ga _1-x N by the simultaneous supply method according to another embodiment of the present invention.

FIG. 16 shows the relationship between CBr ₄ flow rate, which is a carbon source gas, and an effective ionization acceptor density, for carbon doped Al _x Ga _1-x N (x = 0.1).

FIG. 17 shows the relationship between the flow rate of CBr ₄ , the carbon source gas, and the effective ionization acceptor density for carbon doped Al _x Ga _1-x N (x = 0.55).

18 shows the results of measuring IV characteristics of each of carbon-doped Al _x Ga _1-x N (x = 27) and M _x doped Al _x Ga _1-x N (x = 27) according to the present invention.

19 shows contact resistance, sheet resistance, resistivity, and carrier mobility when the Al composition ratio, the flow rate of the carbon source, and the layer thickness are grown with respect to the carbon doped Al _x Ga _1-x N according to the present invention. , The sheet carrier density, and the measurement result of the carrier density are shown.

20 is a conceptual diagram illustrating an example of a layer structure of a nitride based semiconductor light emitting device using carbon doped Al _x Ga _1-x N according to the present invention.

21 is a conceptual diagram illustrating another example of a layer structure of a nitride based semiconductor light emitting device using carbon doped Al _x Ga _1-x N according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention; The following embodiments are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art to which the present invention pertains. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, widths, lengths, thicknesses, and the like of components may be exaggerated for convenience. In addition, when one component is described as "on" or "on" another component, each component is different from each other as well as when the component is "just above" or "on" the other component. This includes cases where there is another component between them. Like numbers refer to like elements throughout.

In the production method of the present invention, the p-type nitride-based semiconductor layer or the III-V compound semiconductor layer, such as the p-type AlGaN semiconductor layer, is organometallic vapor deposition (MOCVD), plasma chemical vapor deposition (PECVD), low pressure chemical vapor phase It can be formed using a vapor deposition technique such as chemical vapor deposition (CVD) such as vapor deposition (LPCVD), or vacuum deposition such as molecular beam epitaxy (MBE).

EMBODIMENT OF THE INVENTION The case where MOCVD is used as one Embodiment of the manufacturing method of the p-type nitride-type semiconductor layer of this invention is demonstrated with reference to drawings.

1 is a process diagram schematically showing a crystal growth step of a p-type AlGaN semiconductor layer on a single crystal substrate, according to an embodiment of the present invention, Figure 2 is a p on a single crystal substrate, according to an embodiment of the present invention It is a flowchart about the supply timing of a growth element before and after growth of a p-type AlGaN semiconductor layer in the crystal growth of the type AlGaN semiconductor layer.

First, referring to FIG. 1, the washed single crystal substrate 11 is prepared and then set in the MOVPE apparatus (FIG. 1 (a)). In addition, a well-known thing can be used for the MOVPE apparatus to be used. As the substrate 11, a single crystal substrate whose main surface has an offset angle in the range of ± 0.1% with respect to the (0001) C surface is used. In addition, it is most preferable to use a sapphire substrate as the single crystal substrate.

Next, a group V source gas is supplied into the MOVPE apparatus for a predetermined time T ₁ (FIG. 1B), and a group V source gas containing a carbon source material after a predetermined time t _{1 has} elapsed after the start of supplying the group III source gas. Is supplied for a predetermined time T ₂ (wherein t ₁ + T ₂ > T ₁ ) (FIG. 1 (c)). In addition, a step of supplying the Group III source gas after a predetermined time t ₂ (where t ₁ + T ₂ -t ₂ > T ₁ ) has elapsed after the supply of the Group V source gas is started, and the Group V source gas is supplied. Perform the process again. As a carrier gas of the group III source gas and the group V source gas, a known gas such as hydrogen gas can be used.

In the Group III source gas supply process and the Group V source gas supply process, the aluminum content of the Al _x Ga _{1 - x} N semiconductor layer (0 <x≤1) is 5 mol% to 100 mol%, and the effective maximum ionization is performed. The acceptor density (NIAD = (N _A ^-- N _D ⁺ )) is preferably carried out in the range of 3 to 7 x 10 ¹⁸ cm ^-3 through capacitance-voltage measurement.

It is preferable to use carbon tetrabromide (CBr ₄ ) as the carbon source material to be mixed with the Group V source gas. Acetylene, on the other hand, is not preferred for use as a carbon source material because of its high reactivity and risk. In addition, since carbon tetrachloride has an etching effect, when the flow rate is increased, the crystal growth rate is extremely lowered and a semiconductor layer is not formed. Therefore, carbon tetrachloride is not suitable for use as a carbon source material. In addition, although carbon tetrabromide also has an etching effect, bromine has a large atomic number compared to chlorine, and is relatively suitable for use as a carbon source material because the chemical reaction force is relatively mild even though it is the same halogen.

When using ammonia gas as a component of the Group V source gas, the nitrogen atom separation ratio of the ammonia gas molecule is closely related to the growth temperature of the p-type AlGaN semiconductor layer, and the growth temperature or substrate temperature of 1190 ° C to 1370 ° C is 1070 ° C. It is preferable to supply the group III source gas and the group V source gas at a growth temperature of ˜1250 ° C. In addition, the optimum growth temperature of the p-type AlGaN semiconductor layer to be deposited is changed depending on the mol% of aluminum contained in the p-type AlGaN semiconductor layer. For example, for AlGaN with an aluminum content of several to 25 mol%, 1190 ° C to 1230 ° C is the optimum growth temperature. However, when increasing the mol% of aluminum contained in the AlGaN to be deposited, the optimum deposition temperature is preferably set to 1190 ℃ ~ 1370 ℃ because it must grow at a high temperature in terms of crystal quality and doping properties.

In addition, the component of the Group V source gas is preferably mixed with a magnesium source material, the amount is about 1/100 to 100 times the gas partial pressure composed of the carbon source material, the NIAD containing carbon and magnesium It is most desirable to measure the capacitance voltage until it is in the range of 3 to 7 × 10 ¹⁸ cm ^-3 . This is because carbon and magnesium atoms contained in the group V source gas are doped at sites of nitrogen atoms in the AlGaN crystal during growth of the p-type AlGaN semiconductor layer, thereby stably carbon doping.

Carbon is doped by repeatedly providing a predetermined overlap time or interval time (I ₁ , I ₂ ) between the step of supplying the group III source gas for a predetermined time and the step of supplying the group V source gas for a predetermined time. P-type AlGaN semiconductor layer is formed. Here, as shown in FIG. 2, an overlap is not set between the supply time T ₁ of the group III source gas and the supply time T ₂ of the group V source gas, and the supply time T ₁ of the group III source gas and the group V source gas are not set. It is preferable to set the interval time between the supply times T ₂ of 0 seconds to 2 seconds. This is because the carbon atom can be stably doped at the site of the nitrogen atom in the AlGaN crystal by setting the interval time between the supply time T ₁ of the group III source gas and the supply time T ₂ of the group V source gas. However, when the interval time is set to 2 seconds or more, the interface of the hetero structure of the manufactured p-type AlGaN crystal layer becomes rough, which is not preferable.

(P-type AlGaN semiconductor layer growth by the method of the present invention)

GaN and AlGaN layers were grown on the (0001) plane of the sapphire substrate according to the conventional reduced pressure organometallic gas phase epitaxy (LP-MOVPE) method. Growth pressure and growth temperature were 40 hPa and 1180 ° C., respectively. TMGa, TMAl, CBr ₄ and NH ₃ were used as raw materials for Ga, Al, C and N, respectively. In addition, the epitaxial growth conditions are as follows.

Set temperature when growing: 1190 ℃ ~ 1370 ℃

Substrate surface temperature: 1070 ℃ ~ 1250 ℃

Source gas pressure at growth: 40 to 200 hPa

V / III ratio (molar ratio / partial pressure ratio): about 200 to 600

Carbon tetrachloride supply: 7 × 10 ^-8 mol / min ~ 1.7 × 10 ^-5 mol / min

Supply amount of cyclopentadienyl magnesium (Cp2Mg): 1.3 × 10 ^-7 mol / min ~ 1.6 × 10 ^-7 mol / min

Supply amount of Group III source gas (trimethylgallium (TMG) and trimethylaluminum (TMAl)): 5 x 10 ^-5 mol / min

In addition, the number of times of supply of the group III source gas and the group V source gas, the supply time T ₁ of the group III source gas, and the supply time T ₂ of the group V source gas are 0 to the interval between the T ₁ and T ₂ . It adjusted suitably so that the desired thickness of a p-type AlGaN semiconductor layer might be obtained on conditions which become 1 second.

The structure of the sample is as follows. A single C-doped AlGaN layer (layer thickness 1 μm) was grown on an undoped AlGaN (layer thickness 2-4 μm) template for Van der Pauw method Hall effect measurements. On the other hand, a thick layer-thick n-type GaN or AlGaN (layer thickness 2-4 탆) template was grown on a hot undoped AIN layer (layer thickness of several nm). Then, for capacitive-voltage (CV) measurement, SIMS analysis, and IV characterization, an undoped GaN active layer (layer thickness of 10 to 15 nm) and a C-doped AlGaN layer (layer thickness of 0.1 to 1.5 μm) were added to the n-type GaN or Growth has continued on AlGaN templates. A thin Mg-doped GaN cap layer (10 nm layer thickness) as an ohmic contact layer was grown on the C-doped AlGaN layer for C-V measurement and fabrication of LEDs.

(Crystal Quality of p-type AlGaN Semiconductor Layer Produced by the Method of the Present Invention)

The crystal quality of the prepared C-doped AlGaN sample was evaluated by X-ray rocking curve analysis using reflection of (0002) plane and (10-12) plane. The X-ray rocking curve analysis results were then measured by transmission electron microscopy data for (000) and (0002) diffraction spots and (1020) planes using electron beams incident along the [1-100] direction. According to the X-ray rocking curve analysis, the full width at half maximum (FWHM) for the (0002) plane ω scan and the (10-12) plane φ scan was around 120 to 150 arcsec and 300 to 350 arcsec. The density of dislocations composed of screw-type dislocations and mixed-type dislocations of the C-doped p-type AlGaN layer and the density of mixed dislocations and edge dislocations are 2 to 2, respectively. It was estimated to be ^{3 ~ 2 × 10 9 cm -3} - 5 × 10 7 cm -3 and 7 × 10 ⁸ cm. X-ray rocking curve analysis showed that the crystal quality of C-doped AlGaN was very similar to undoped AlGaN grown on c-plane sapphire substrate by the same growth conditions and same layer structure.

(Optical Properties of C-doped AlGaN)

The optical properties of C-doped AlGaN and undoped AlGaN were compared for the purpose of clarifying the carbon effect on the luminescence properties and to find the energy level associated with the carbon acceptor of the (0001) face of the C-doped AlGaN.

FIG. 3A shows a low temperature emission (PL) spectrum obtained from an undoped AlGaN having a composition ratio of aluminum (hereinafter also referred to as an "Al composition ratio") of 8%. One main (maximum) emission and three weak emission It was measured to be at E _m = 3.685 eV, E ₁ = 3.650, E ₂ = 3.598 eV and E ₃ = 3.498 eV, respectively. FIG. 3B is C-doped AlGaN with an Al composition ratio of 9%, with one major (maximum) emission, one second largest radiation (also referred to as "sub-peak radiation"), and weak radiation It was measured to be at E _m = 3.739 eV, E ₁ = 3.710 and E ₃ = 3.570 eV, respectively.

Figures 3 (a) and (b) show the excitation of a 193 nm pulsed excimer laser in the ML-2100-S optical attenuator of METROLUX Co., Ltd. Photoluminescence (PL) spectra obtained in an undoped AlGaN layer and a C-doped AlGaN layer having an Al composition ratio of about 8-9% are shown.

The main luminescence, i.e. the maximum peak, is shown at E _m = 3.685 eV and is related to band edge-emission in undoped AlGaN, as shown in FIG. In comparison, it was measured that one main radiation and three weak radiations were at E _m = 3.685 eV, E ₁ = 3.650, E ₂ = 3.598 eV and E ₃ = 3.498 eV, respectively. The calculated photon energy difference between one major and three weak emissions is (E _m -E ₁ ) = 35 meV, (E _m -E ₂ ) = 87 meV, (E _m -E ₃ ) = 187 meV, respectively.

The present inventors observed the spectral spread of PL emission in C-doped AlGaN shown in Fig. 3B. The photon energy of each emission was carefully measured, with a maximum peak emission of E _m = 3.739 eV, which is related to the band edge emission in AlGaN of C-doped, but almost different from the sample (a) of FIG. Not relevant The second largest emission observed near the maximum peak, ie the sub peak emission, is E ₁ = 3.710 eV. And the weak radiation was measured to be at E ₃ = 3.570 eV.

The sub-peaks of E ₁ and the emission intensity of the weak emission at E ₃ are highly dependent on the flow of CBr ₄ . Therefore, the inventors concluded that the two emissions are related to the carbon acceptor of C-doped AlGaN.

The difference in photon energy between the maximum peak emission and the sub peak or weak emission is (E _m -E ₁ ) = 29 meV and (E _m -E ₃ ) = 169 meV, respectively.

Considering free and bound exciton, there is a need to further analyze and discuss the difference in photon energy. However, E ₁ and E ₃ in undoped AlGaN and E ₁ and E ₃ in C-doped AlGaN are occurring in carbon acceptors of undoped and C-doped AlGaN. We estimated 29-35 meV and 169-187 meV as the two energy levels of the carbon acceptor for the shallow acceptor level and the deep acceptor level, respectively. The shallow acceptor energy level (E _m -E ₁ ) = 29 meV has a high hole density and is thought to play an important role in connection with the p-type conductivity of C-doped AlGaN.

(Hall effect measurement)

Hall effect measurement of AlGaN with Al composition ratio of 10% was carried out using the following simple structure.

A single C-doped AlGaN layer (layer thickness 1 μm) was grown on an undoped AlGaN (layer thickness 2-4 μm) template without a magnesium doped (Mg-doped) GaN cap layer. Therefore, for the measurement of van der Pauw geometry Hall effect, Mg-doped p-type GaN cap layer is not formed in case of GaN and AlGaN with Al composition ratio up to 10%.

The inventors first attempted carbon doping on the (0001) surface of GaN, but p-type conductivity was not realized. The experimental results according to the present invention strongly suggest that a small amount of aluminum plays an important role in the p-type conductivity of AlGaN, and that aluminum is necessary for the p-type conductivity of the (0001) plane of AlGaN. On the other hand, the inventors have experimentally realized p-type conductivity in C-doped AlGaN. The (0001) planes of the undoped AlGaN layer were all n-type, and the background free electron dendity of the background was 3-9 × 10 ¹⁵ cm ⁻³ . In general, the hole mobility of these samples was in the range of 20-80 cm ² / V · s at room temperature.

4 (a) and 4 (b) are graphs showing the dependence of free electron density on the flow rate of CBr ₄ for carbon doped Al _0.1 Ga _0.9 N, by Van der Pauw geometry Hall effect measurement. Obtained. The data of the hollow and black circles show the conductivity of n-type (free electron density) and p-type (free hole density) of Al _0.1 Ga _0.9 N, respectively.

The inventors have found that the n-type electrical conductivity of C-doped AlGaN with free electron density in the range of n ≒ 3 × 10 ¹⁴ cm ^-3 to 9 × 10 ¹⁵ cm ^-3 when the flow rate of CBr ₄ is 0.06 to 0.3 μmol / min. Observed.

When the flow rate of CBr ₄ was 0.7 μmol / min, the free electron density decreased to n ≒ 5 × 10 ¹⁴ cm ⁻³ . When the flow rate of CBr ₄ is about 3 μmol / min or more, the electrical conductivity changes from n type to p type, and with the increase of CBr ₄ flow rate, the free hole density is 3 ³ 4 × 10 ¹³ cm ^{- 3} to 3 × 10 ¹⁸ cm ^-3 increased sharply. The maximum value of the free hole density was p ≒ 3.2 × 10 ¹⁸ cm ⁻³ obtained when the flow rate of CBr ₄ was 5 μmol / min, and the sheet carrier density was equivalent to 7.5 × 10 ¹⁴ cm ⁻² .

In this case, the monolayer electrical conductivity, sheet resistance, and electron mobility of C-doped AlGaN of 2.3 µm layer thickness were 20 ohmcm, 8.6 × 10 ⁴ ohm / cm ² , 0.4 cm ² / V · at room temperature. s. The hole mobility of C-doped AlGaN in the p-type region varied from 0.4 to 20 cm ² / V · s at room temperature.

(C-V measurement)

NIAD (Net Ionized Acceptor Densities) = (N_A                 ^- -N_D                 ⁺) (N_A                 ^- And N_D                 ⁺C-V was measured at room temperature for C-doped AlGaN using an ECV-Pro-type nanometer C-V system to determine the NIAD defined by ionized acceptor and donor density, respectively. For reference, the KOH concentration of the electrolyte used was 0.001 to 0.005 mol%, and far ultraviolet rays were obtained in a mercury-xenon lamp having a wavelength light source of 185 to 2000 nm. Acceptor N on hand_A                 ^-And donor N_D                                  ⁺The atomic density of was measured independently by SIMS analysis. C-V measurements can show the p-type conductivity of C-doped AlGaN.

5 (a) shows Mg-doped GaN (layer thickness 0.08 μm) / C-doped AlGaN (molar concentration of aluminum 55%, layer thickness 1.0 μm) / Si doped AlGaN (molar concentration of aluminum 55%), layer thickness 2-4 μm) shows the depth profile of the NIAD obtained by CV measurement of the structure of the sample. The AlGaN semiconductor layer of FIG. 5 (a) is manufactured by simultaneously doping carbon (C) and magnesium (Mg). Meanwhile, the AlGaN semiconductor layer, which is the measurement target in FIG. 5B, is doped with C only. 5 (b) shows GaN (layer thickness 0.08 μm) / C-doped AlGaN (molar concentration of aluminum 55%, layer thickness 1.0 μm) / Si doped AlGaN (molar concentration 55% of aluminum), layer thickness 2 Depth profile of the NIAD obtained by CV measurement of the structure of the sample composed of ~ 4㎛). As can be seen by comparing Figs. 5A and 5B, Mg-doped p-type GaN is believed to reduce the effect of the "surface state" of CV measurement samples with high carbon content and low carbon content. It is important to get reliable and reliable CV measurement results.

The electrical conductivity of the C-doped AlGaN semiconductor layer with a composition ratio of Al of 0.55 is p-type, and its NIAD is 6-7 × 10 for a depth of 1.2 μm at 0.18 μm, as shown in FIG. ^{It was 18} cm <^-3> . On the other hand, the NIAD of Mg-doped GaN was slightly lower, which was 5 × 10 ¹⁸ cm ^-3 . On the other hand, as AlGaN semiconductor layer of carbon doped is only shown in 5 (b) also, a value of about 0.09㎛ NIAD at a depth of about 0.54㎛ about 1 × 10 ¹⁷ cm ^{- 3} ~ about 2 × 10 ¹⁸ cm ^- Not only was it scattered between ³ , but it was also unstable with a mixture of p-type and n-type.

6A and 6B are graphs summarizing C-doping characteristics of AlGaN having Al composition ratios of 10% and 55%, respectively. , NIAD is from ^{3 × 10 16 cm -3 3 ×} 10 18 cm , as Fig. 6 (a) and changing the flow rate of the CBr ₄ as shown in (b) ^- was able to be controlled easily through ^3.

The maximum NIAD is (6 to 7) x 10 ¹⁸ cm ^-3 , and as shown in FIG. 5 (a), it is a value obtained for AlGaN having an Al composition ratio of 55%. However, the flow rates of CBr _{4 from which} the same NIAD (eg 1 × 10 ¹⁸ cm ⁻³ ) can be obtained are different for AlGaN with 10% aluminum and AlGaN with 55% aluminum.

That is, the experiment of the present invention requires a larger flow rate of CBr ₄ to obtain the same NIAD for AlGaN having a relatively low Al composition ratio.

This result can be assumed to reflect the fact that p-type conductivity is not realized in C-doped GaN, but is realized in C-doped AlGaN. In fact, according to the C-doped experimental results of AlGaN, for AlGaN having 20% of aluminum, when the flow rate of CBr ₄ is the smallest, for example, the same NIAD value of 1 × 10 ¹⁸ cm ⁻³ can be obtained. . This result also reflects the relationship between AlGaN carbon and aluminum atoms.

SIMS analysis provided more important information about carbon doping. 7A and 7B show Mg-doped GaN (layer thickness 0.08 μm) / C-doped AlGaN (molar concentration of aluminum = 27%, layer thickness 0.11 μm) / undoped GaN (layer thickness 15 nm) / Results of SIMS analysis of a double heterostructure composed of Si-doped AlGaN (molar concentration of aluminum = 10%; layer thickness 3 μm) are shown. The Mg concentration of the cap GaN layer was determined to be 5 × 10 ¹⁹ cm ⁻³ in another SIMS analysis. Secondary ionic strengths of aluminum and gallium are indicated for reference.

By SIMS analysis of the carbon concentration of the C-doped AlGaN layer, important information on carbon doping could be obtained. 7 (a) and 7 (b) show the results of SIMS analysis of a sample prepared by varying the amount of carbon doping for the AlGaN layer by varying the flow rate of CBr ₄ , which is a carbon feed material source. By the changing the flow rate of the CBr ₄ as shown in (a) and (b) of Figure 7, the carbon density of each of ^{(4 ~ 5) × 10 18} cm - 3 and ^{(0.9 ~ 1) × 10 18} cm - ^It was found to change to ³ and control the amount of carbon doping. In addition, in the experiment of the present invention, it was also possible to set the doped carbon concentration to a maximum of 7.3 × 10 ¹⁸ cm ⁻³ . Before starting the SIMS analysis, the system was carefully calibrated for carbon analysis by standard methods, using AlGaN samples implanted with carbon ions. In addition, the AlGaN sample has the same Al composition ratio as used in the SIMS analysis, the AlGaN sample for ion implantation was grown under the same growth conditions.

(Electrical Activity of Carbon Acceptor in AlGaN)

For the samples used to obtain FIGS. 7A and 7B, the NIAD of the carbon acceptor in p-type AlGaN (composition ratio of Al 27%) was 5 × 10 ¹⁸ cm ⁻³ . Thus, the electrical activation rate of the carbon acceptor in AlGaN was measured using the carbon concentration and NIAD measured in the SIMS analysis, as described above, and this sample was estimated to be about 68%.

The inventors also evaluated the electrical activation rate of the carbon acceptor using several other samples. 8 is a graph showing the dependence of the carbon acceptor's electrical activation ratio on the aluminum composition ratio, and the electrical activation ratio was evaluated using carbon atom density (measured by SIMS analysis) and NIAD (measured by CV measurement). However, it appears to be around 55-71%.

Three experimental results for the carbon acceptor electrical activation ratio of AlGaN (27% of Al composition) are indicated by error bars. According to the experimental results of the present invention, it was found that the electrical activation ratio of the carbon acceptor in AlGaN (composition ratio of Al 27%) is in the range of 55 to 71%. The carbon acceptor electrical activation ratio for AlGaN at 20% Al composition ratio is thought to be slightly greater than or nearly equal to the electrical activation ratio for AlGaN at 27% Al composition ratio, as shown in FIG. In other words, it shows that a shallow carbon acceptor level exists.

On the other hand, the NIAD of the magnesium doped (Mg doped) p-type GaN layer was measured for the samples used to obtain (a) and (b) of FIG. The NIAD for the Mg acceptor was 4-5 × 10 ¹⁸ cm ⁻³ , and the Mg concentration of Mg-doped p-type GaN was determined to be 5 × 10 ¹⁹ cm ⁻³ by SIMS analysis. Thus, the electrical activation rate of GaN's Mg acceptor was estimated to be about 8-10%. The electrical activation rate of the Mg acceptor is required in three samples and also appears as error bars at the 0% Al composition ratio shown in FIG. 8. According to the experimental results of the present invention, the ratio of the carbon acceptor electric activation of AlGaN having an Al composition ratio of 20 to 27% is greater than that of the Mg acceptor of GaN.

to a deeper examine the origin of the p-type conductivity and ^{acceptor-electrical} activation ratio of _(A N / _A N) is calculated as a function of the absolute temperature for the different activation energy E _A.

^{_{(N A - / N A)}} = exp {-E A / 2kT}

Where k and T are Boltzmann's constant and absolute temperature, respectively.

9 is a graph evaluating activation energies of Al _0.27 Ga _0.73 N carbon acceptors and GaN Mg acceptors using experimental electrical activation ratios of carbon and magnesium acceptors at room temperature. In addition, in FIG. 9, the electrical activation ratio calculated for the activation energy from E _A = 20 meV to 240 meV is indicated by a solid line.

Therefore, the present inventors can evaluate that the activation energy for AlGaN carbon acceptors having an Al composition ratio of 27% is in the range of 22 to 30 meV, and the activation energy for Mg acceptors in GaN is in the range of 110 to 130 meV. have. The evaluation value of the activation energy of the carbon acceptor is a value close to the carbon acceptor level in AlGaN having an Al composition ratio of 27% measured in the PL emission spectrum.

Table 1 and Table 2 summarize the electrical characteristics of the p-type AlGaN semiconductor layer prepared by growing on the (0001) surface of the sapphire substrate according to the above-described LP-MOVPE method based on the same conditions as the above-described epitaxial growth conditions. Table. As can be seen from this table, even when the aluminum content is increased, it can be seen that the electrical conductivity of the AlGaN is maintained by doping carbon into the AlGaN semiconductor layer under the predetermined conditions disclosed in the present invention.

Table 1

Example	Al composition ratio (%)	Layer thickness (㎛)	Flow rate of CBr 4 (μmol / min)	Contact resistance R c (KΩ)	Sheet Resistance R s (Ω / cm 2 )
A	10	5.5	2.6	2000-3500	2700000
B	10	2.3	5.1	1000-1800	930000
C	10	2.3	5.1	100-150	86000
D	25	0.4	One	150-200	(4.0-4.5) E + 03
E	77	0.4	13	95-120	(5.0 ~ 7.3) E + 03

TABLE 2

Example	Resistivity (Ωcm)	Carrier Mobility (cm 2 / V · s)	Sheet Carrier Density P s (cm -2 )	Carrier Density P (cm -3 )
A	1500	0.14	1.6E + 13	2.9E + 16
B	210	0.19	3.5E + 13	1.5E + 17
C	20	0.097	7.5E + 14	3.3E + 18
D	0.1-0.19	12-16	+ (1.0 ~ 1.2) E + 14	+ (2.6 ~ 2.9) E + 18
E	2.2 to 2.9	0.30-0.36	+ (2.0 ~ 3.7) E + 14	+ (6.0-9.3) E + 18

As described above, according to the above-described embodiments, since the carbon is stably doped, the present invention can provide a method of manufacturing a carbon-doped p-type gallium nitride based semiconductor layer having improved productivity. In addition, according to the above production method, since the p-type nitride semiconductor layer having a high aluminum content can be produced, the p-type nitride semiconductor layer produced by the production method of the present invention has high breakdown voltage characteristics and excellent electrical properties, It has transparent optical properties and high electrical conductivity up to the deep ultraviolet region. Therefore, according to the above manufacturing method, since a p-type layer having a low resistance can be realized even in a power supply device carrying a large current, a higher performance nitride-based power control device can be realized.

Next, a method of manufacturing a carbon-doped group III-V compound semiconductor as a p-type impurity according to another embodiment of the present invention will be described. In this embodiment, the method of manufacturing a III-V nitride semiconductor layer carbon-doped as a p-type impurity is a case where the III-V nitride semiconductor layer is Al _x Ga _1-x N, and the MOCVD method is used. An example will be described.

First, a substrate for epitaxially growing Al _x Ga _1-x N is prepared. If the main surface is a crystal surface substrate having a surface in the range of ± 0.1% with respect to the C surface or the crystal surface corresponding to the C surface, not only a sapphire substrate but also various substrates such as silicon substrate, silicon carbide substrate, gallium nitride substrate, and aluminum nitride substrate can be used. Can be. In this specification, the interlayer refers to a nitride based semiconductor layer grown on a substrate.

If the principal surface is a substrate having a surface in the range of ± 0.1% of the C plane or the crystal plane corresponding to the C plane, vapor deposition can be used to deposit group III atoms and group V atoms alternately on the substrate by 5-7 molecular layers. Will be.

Sources of Group III elements used to grow Al _x Ga _1-x N include, for example, trimethylgallium (TMG), trimethylaluminum TMA; A source of (CH3) 3Al) and cyclopentadienyl magnesium (Cp2Mg) is used, and a V-group element is, for example, can be used with ammonia (NH _3). Carrier gas carrying the source, for example, may be a hydrogen (H _2). However, such materials are illustrative and not limited to, of course.

As a source of carbon (C) doping, for example, carbon tetrabromide (CBr ₄ ) is used. In the present invention, the carbon doping source is not limited to carbon tetrabromide (CBr ₄ ), but acetylene is not preferable to use as a carbon source material because it is highly reactive and dangerous. In addition, carbon tetrachloride has an etching effect, and when the flow rate is increased, the crystal growth rate is extremely lowered and the film does not grow. Therefore, it is not preferable to use it as a carbon source material. In addition, although carbon tetrabromide also has an etching effect, since the atomic number of bromine is larger than that of chlorine, the carbon tetrabromide is a carbon source material because it is the same halogen but has a relatively mild chemical reaction force.

Examples of growth conditions by the MOVPE method are as follows.

Set temperature during growth: 1180 ℃ or more 1370 ℃ or less

Substrate surface temperature: 1070 ℃ or more and 1250 ℃ or less

Source gas pressure at growth: 4000 or more and 20000Pa or less

Component ratio of group V element / group III element: 5 or more and 600 or less

CBr ₄ Supply: 7 × 10 ^-8 mol / min or more 1.7 × 10 ^-5 mol / min or less

Cp2Mg supply: 1.3 × 10 ^-7 mol / min ~ 1.6 × 10 ^-7 mol / min

Source gas (TMG and TMAl) supply of Group III elements: 5 × 10 ^-5 mol / min

In addition, the growth conditions are one example, if Al _x Ga _1-x N can be grown by the MOVPE method, it is not limited thereto. However, the separation ratio of nitrogen atoms in the ammonia gas molecule is highly temperature dependent. When ammonia gas is used as a component of the source gas of the group V element, the dissociation ratio of nitrogen atoms in the ammonia gas molecule is closely related to the growth temperature of the p-type AlGaN semiconductor layer. Therefore, it is preferable to supply the group III source gas and the group V source gas under conditions in which the set temperature during growth is in the range of 1180 ° C or more and 1370 ° C or less, and the substrate temperature is in the range of 1070 ° C or more and 1250 ° C or less.

In addition, when the growth temperature is lower than 1180 ° C, carbon becomes difficult to enter the site of the nitrogen atom in the AlGaN crystal. Therefore, it is preferable that growth temperature is 1180 degreeC or more. On the other hand, when growth temperature is higher than 1370 degreeC, since a gallium atom volatilizes, 1370 degreeC or less of growth temperature is preferable.

In addition, the optimum growth temperature of the deposited AlGaN semiconductor layer is preferably changed according to the aluminum content (mol%) contained in the AlGaN semiconductor layer. For example, for AlGaN having an aluminum content of several to 25 mol%, the optimum growth temperature is 1180 ° C. or more and 1230 ° C. or less. However, when increasing the aluminum content (mol%) contained in the grown AlGaN, it is necessary to grow at high temperature in view of crystal quality and doping characteristics. The optimum growth temperature is preferably set to 1180 ° C or more and 1370 ° C or less.

The reason why the source ratio of the group V element and the group III element is in the range of 5 to 600 is because carbon tends to enter the site of the nitrogen atom layer in the AlGaN crystal in this range. By setting the source ratio of the source of the group V element and the group III element to 5 to 600, the amount of carbon doping can be maximized at the site of the nitrogen atom layer in the AlGaN crystal. In addition, when the set temperature at the time of growth is 1250 degreeC or more, if the source ratio of the source of a group V element and a group III element is 5 or more, carbon will fully enter the site of the nitrogen atom layer in an AlGaN crystal. On the other hand, when the set temperature at the time of growth is less than 1250 degreeC, the source ratio of the source of a group V element and a group III element is preferably 200 or more and 600 or less.

Hereinafter, a detailed gas supply method will be described in the method of manufacturing a III-V nitride-based semiconductor layer doped with carbon as a p-type impurity according to embodiments of the present invention according to FIGS. 10 to 12 and 15. .

When the III-V nitride semiconductor layer is grown by the MOVPE method, the source gas supply method, the simultaneous supply of the III-source gas of the group III element and the V-source gas of the group V element at the same time There is a supply method and an alternate supply method for alternately supplying a source gas of a group III element and a source gas of a group V element.

FIG. 10 is a first example of one cycle of a gas supply method when epitaxially growing Al _x Ga _1-x N by an alternate supply method.

As shown in FIG. 10, in the reactor, Group III elements Ga and Al sources trimethyl gallium (TMG) and trimethyl aluminum (TMA; (CH ₃ ) ₃ Al) were supplied for T ₁ hour and cyclopenta, a source of Mg Dienyl magnesium (Cp 2 Mg) overlaps with T ₁ hour and is also supplied for t ₁ hour, which is shorter than T ₁ hour.

After the time T ₁ elapsed, ammonia (NH ₃ ) was supplied as an N source of Group V element for T ₂ hours at interval time I ₁ , and carbon tetrabromide (CBr ₄ ) as a carbon doping source overlapped with T ₂ time. It is also supplied for t ₂ hours which is shorter than T ₂ hours.

After the T ₂ period has elapsed, the interval time I ₂ is supplied, the Group III element is supplied for T ₁ hour, the Mg component is supplied for t ₁ hour, the Group V element is T ₂ hours, and the carbon doped component is t for the interval time I ₁ . _{The two-} hour cycle is repeated several times. Then, Al _x Ga _1-x N can be grown to a desired thickness.

Interval time I ₁ and interval time I ₂ may be up to 2 seconds. Interval time I ₁ and interval time I ₂ may be 0 seconds. However, without interval time I ₁ and interval time I ₂ , there is a possibility that the source gas of the group III element and the source gas of the group V element are mixed. Therefore, whenever possible, interval time I ₁ and interval time I ₂ should be prepared. On the other hand, when the interval time I ₁ and the interval time I ₂ are set to each other for 2 seconds or more, the crystal quality of the interface of the grown film can be greatly reduced due to re-evaporation and adsorption or capture of residual gas. Therefore, it is not preferable to set the interval time I ₁ and the interval time I ₂ for 2 seconds or more, respectively.

The film grown by the gas supply method according to the first example using the growth conditions by the MOVPE method may be stably a p-type AlGaN semiconductor layer. The reason for this is that when a substrate having a surface in the range of ± 0.1% of the C plane or the crystal plane corresponding to the C plane is used, the group III atomic layer and the group V atomic layer are alternately applied to the substrate by 5 to 7 molecular layers, respectively. This is because carbon accumulates in the group V atomic layer.

Carbon becomes an n-type impurity when entering the group III atomic layer and becomes a p-type impurity when entering the group V atomic layer. That is, according to the growth method according to the present invention, the group III atomic layer and the group V atomic layer are alternately laminated on the substrate by about 5 to 7 molecular layers, respectively, and carbon enters the group V atomic layer. Therefore, according to the growth method according to the present invention, it is possible to stably produce a p-type AlGaN semiconductor layer.

FIG. 11 is a second example of one cycle of the gas supply method when epitaxially growing Al _x Ga _1-x N by an alternate supply method.

In the first example, cyclopentadienyl magnesium (Cp ₂ Mg) overlaps with T ₁ hour and is supplied only at t ₁ hour, which is shorter than the T ₁ period. However, in the second example, cyclopentadienyl magnesium (Cp ₂ Mg) is supplied for a time equal to t ₂ hours at which carbon tetrabromide (CBr ₄ ), which is a carbon doping source, is supplied. The other process of the second example is almost the same as that of the first example.

12 is a third example of one cycle of the gas supply method when epitaxially growing Al _x Ga _1-x N by an alternate supply method.

The third example is different from the first example or the second example, except that cyclopentadienyl magnesium (Cp ₂ Mg) is always flowed into the reactor. Other processes of the third example are almost the same as the first example or the second example.

Even if the source gas of Mg continues to be supplied to the reactor, there is no particular problem in the process of growing the AlGaN semiconductor layer. Therefore, when continuing supplying the source gas of Mg, it is not necessary to control the supply timing of Mg source gas in detail, and can simplify a manufacturing process.

FIG. 13 shows an AlGaN semiconductor layer obtained by CV measurement (ionization impurity concentration measurement) for a layer in which an Al _x Ga _1-x N semiconductor (x = 0.55) was grown under the following growth conditions by the source gas supply method of the first example; Hole concentration along the depth direction.

Set temperature during growth: 1180 ℃ or more 1230 ℃ or less

Substrate surface temperature: 1070 ℃ or more and 1110 ℃ or less

Source gas pressure at growth: 4000 or more and 20000Pa or less

Source ratio of group V element source / group III element: 5 or more and 600 or less

CBr ₄ Supply: 7 × 10 ^-8 mol / min or more 1.7 × 10 ^-5 mol / min or less

Cp ₂ Mg Supply: 1.3 × 10 ^-7 mol / min ~ 1.6 × 10 ^-7 mol / min

Source gas (TMG and TMAl) supply of Group III elements: 5 × 10 ^-5 mol / min

In addition, the ionization impurity concentration generates carriers in the added impurity, and indicates that the ionization itself is negative or positive ionized. Ionization impurities are ions immobilized in the crystal, not free carriers. Thus, C-V measurements make it possible to analyze the exact appearance of doping without being affected by the internal electric field of the crystal. The device used in this measurement is ECV-Pro from Nanometrics.

According to FIG. 13, p type | mold is shown to the thickness of 0.1 micrometer on the surface of an Al _x Ga _1-x N semiconductor layer. However, at depths of 0.1 µm or more, n-type and p-type are inverted and an unstable portion exists.

On the other hand, Fig. 14 shows an AlGaN semiconductor layer by CV measurement (ionization impurity concentration measurement) for a layer in which an Al _x Ga _1-x N semiconductor (x = 0.55) was grown by the source gas supply method of the second example with the same growth conditions. Is the hole concentration along the depth direction. According to this, the p-type was stably exhibited up to 1.3 micrometers in depth of a layer. This shows that carbon is actively contained in the group V atomic layer by simultaneously flowing the source gas of Mg and the carbon source gas while supplying the source gas of the group V element.

The second example is to supply the source gas of Mg together while supplying the carbon source gas. As shown in the measurement results in FIGS. 14 and 15, when the AlGaN semiconductor layer is grown by the method of supplying the source gas of the first example and the method of supplying the source gas of the second example, respectively, under the same conditions as the growth temperature, the source gas of the second example Experimental results show that the layer grown by the feeding method has more stable hole concentration.

The reason why carbon is more likely to enter the group V atomic layer than when using the method of the first example when using the method of the second example is as follows. According to the second example, cyclopentadienyl magnesium (Cp ₂ Mg) is supplied at the same time as the source gas of the Group V element, so that Mg is doped into the Group V atomic layer. It is estimated that Mg has the effect of introducing a defect into an AlGaN crystal. For this reason, doping Mg at a concentration much lower than the carbon concentration in the Group V atomic layer results in defects in the AlGaN crystal to the extent that Mg does not damage the hetero interface of the AlGaN crystal and allows carbon to enter the Group V atomic layer. Because it is possible to increase.

Therefore, the gas supply method according to the third example also has the same effect as the second example because the Mg source and the carbon component are supplied as in the second example.

FIG. 15 is a fourth example of one cycle of the gas supply method when epitaxially growing Al _x Ga _{1- x} N by the simultaneous supply method.

In the fourth example, the source of the group V element N during the time T ₁ , which is the time when trimethylgallium (TMG) and trimethylaluminum (TMA; (CH ₃ ) ₃ Al) sources of group III elements Ga and Al are supplied into the reactor Phosphorous ammonia NH ₃ ) is also supplied for the same time (T ₂ hours). Further, the starting material cyclopentadienyl magnesium (Cp ₂ Mg) as the raw material carbon tetrabromide (CBr ₄₎ for carbon doping of Mg is overlapping with T ₁ time, and T ₂ hours, more also T ₁ time, and T ₂ sigan It is supplied for a short time t ₂ hours. Then, Al _x Ga _{1- x} N is grown to the desired thickness.

In the fourth example, unlike the alternate supply, the source ratio of the group V element source / group III element is preferably as small as possible in the range of 5 or more and 600 or less. When the group V atoms are supplied as depleted as possible, carbon tends to enter the group V atomic layer.

As described above, various gas supply methods have been described. However, both of the alternate supply method and the simultaneous supply method use a group III atomic layer when a substrate having a surface in the range of ± 0.1% of the crystal plane corresponding to the C plane or the C plane is used. The and group V atomic layers are alternately stacked on the substrate by about 5 molecular layers, respectively, and carbon enters the group V atomic layer. Therefore, by using a substrate having a surface in the range of ± 0.1% with respect to the C plane or the C plane, it is possible to stably grow the p-type AlGaN semiconductor layer by either the alternate supply method or the simultaneous supply method. Do.

However, as mentioned above, the co-feeding method needs to supply the Group V atoms as much as possible. Therefore, the simultaneous supply method has a limited group V element source / Group III element source ratio. The alternating feeding method, on the other hand, is a growth method that not only can alleviate the ratio limitation of the group V element source / group III element source significantly, but also allow carbon to be added to the group V atomic layer more actively than the simultaneous supply method. .

FIG. 16 shows the relationship between the flow rate of CBr ₄ , a carbon source gas, and the effective ionization acceptor density at carbon doped Al _x Ga _{1 - x} N (x = 0.1). According to FIG. 16, if the flow rate of CBr ₄ exceeds at least 12 μmol / min, after the effective ionization acceptor density reaches 10 ¹⁶ cm ⁻³ , the effective ionization as the flow rate of CBr ₄ increases It can be seen that the acceptor density increases in proportion.

FIG. 17 shows the relationship between the flow rate of CBr ₄ , the carbon source gas, and the effective ionization acceptor density at carbon _- doped Al _x Ga _{1 - x} N (x = 0.55). 17 shows that five substrates were prepared, various layers were grown by varying the flow rate of CBr ₄ on each of the five substrates, and the effective ionization acceptor density was measured for each layer of each substrate. The result is. ○, ●, ▲, △, □ display is to a certain substrate, it is the same display is the flow rate of CBr ₄ grown on the same substrate as other layer. Therefore, the plot of the same mark in FIG. 17 shows the effective ionization acceptor density of the layer grown under the same growth conditions (substrate offset surface, substrate surface temperature, source gas pressure during growth, etc.) except for the flow rate of CBr ₄ . Shows. Therefore, the relationship between the flow rate of CBr ₄ and the effective ionization acceptor density is indicated.

According to FIG. 17, it can be seen that when the flow rate of CBr ₄ increases under any growth conditions, the effective ionization acceptor density increases in proportion to each other. When the flow rate of CBr ₄ is controlled, the effective ionization acceptor is controlled. You can control the density of the acceptor. Also in FIG. 17, as in the case of Al _x Ga _{1 - x} N (x = 0.1), when the flow rate of CBr ₄ exceeds at least 11 μmol / min, the effective ionization acceptor density reaches 10 ¹⁶ cm ⁻³ . Afterwards, it can be seen that as the flow rate of CBr ₄ increases, the effective ionization acceptor density increases proportionally.

According to the above experiment, it can be seen that even if the Al composition ratio of Al _x Ga _{1- x} N is increased, the density of the effective ionization acceptor can be controlled by adjusting the flow rate of CBr ₄ .

FIG. 18 is a result of measuring IV characteristics of each of carbon-doped Al _x Ga _{1 - x} N (x = 0.27) and Mg-doped Al _x Ga _{1 - x} N (x = 0.27) according to the present invention.

According to FIG. 18, in the case of M _x doped Al _x Ga _{1 - x} N (x = 0.27), even though a bias voltage of about 9 V is applied, only an injection current of about 1 mA flows. According to the doped Al _x Ga _{1 - x} N (x = 0.27) is applied to a bias voltage of about 9V, it can be seen that a current of 20mA flows.

These results show that the carbon doped Al _x Ga _{1 - x} N (x = 0.27) according to the present invention has a very low resistance compared to the M _x doped Al _x Ga _{1 - x} N (x = 0.27). Therefore, when carbon-doped Al _x Ga _{1 - x} N (x = 0.27) according to the present invention is used as the p-type cladding layer, the p-type electrode can be directly stacked without passing through the contact layer.

FIG. 19 shows contact resistance, sheet resistance, resistivity, carrier mobility, sheet when carbons doped Al _x Ga _{1 - x} N are grown by varying the Al composition ratio, flow rate and layer thickness of the carbon source. It is a measurement result of carrier density and carrier density.

According to the manufacturing method of the present invention, the carrier density can be realized up to (6.0 to 9.3) E +18 while increasing the composition of carbon-doped Al _x Ga _{1 - x} N aluminum to about 70%.

20 is a conceptual diagram illustrating an example of a layer structure of a nitride based semiconductor light emitting device using carbon doped Al _x Ga _1-x N according to the present invention.

Therefore, in addition to the layer of FIG. 20, for example, impurities doped in the p-type nitride semiconductor layer 5 between the light-emitting layer 4 and the p-type nitride-based semiconductor layer 5 do not diffuse into the light-emitting layer 4. The cap layer to be formed may be appropriately formed.

Reference numeral 1 is a substrate. The substrate is a crystalline surface substrate whose main surface has a surface in the range of ± 0.1% with respect to the C surface or the crystal surface corresponding to the C surface. If the main surface is a crystal surface substrate having a surface in the range of ± 0.1% of the crystal surface corresponding to the C surface or C surface, various substrates such as a sapphire substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and an aluminum nitride substrate may be used.

2 is a buffer layer. The buffer layer is a layer which prevents defects from occurring due to a difference between the lattice constant of the substrate and the lattice constant of the nitride semiconductor layer laminated on the substrate. As the buffer layer, it is possible to reduce defects in the n-type nitride based semiconductor layer 3 using AlN, AlGaN, or the like having the substrate 1, the n-type nitride based semiconductor layer 3, and an intermediate lattice constant. The buffer layer may be a superlattice structure of AlN and AlGaN.

Reference numeral 3 is an n-type nitride semiconductor layer. The n-type nitride semiconductor layer may be formed of AlGaN, GaN, GaInN, or the like. Although not shown, the n-type nitride semiconductor layer may be formed by laminating an n-type contact layer on which n-type electrodes are stacked and an n-type cladding layer disposed on the light emitting layer 4 side. The n-type contact layer may also serve as an n-type cladding layer. As n-type impurity, Si, Ge, etc. are preferable, for example.

Moreover, although the n-type contact layer in which n-type electrodes are laminated | stacked, and the n-type cladding layer arrange | positioned at the light emitting layer 4 side by way of the n-type nitride-type semiconductor layer 3 structure were mentioned, it is not limited to this. For example, in the n-type nitride-based semiconductor layer 3, the n-type nitride-based semiconductor layer disposed on the light emitting layer 4 side has an n-type nitride system having a band gap larger than the band gap of the light emitting layer 4 like the n-type cladding layer. Instead of the semiconductor, the n-type nitride semiconductor having the same band gap as the light emitting layer 4 can be formed.

4 is a light emitting layer. The emission layer 4 may be a single quantum well (SQW) including GaN, InGaN, AlGaN, or AlGaInN, or a multi-quantum well (MQW) structure in which a well layer and a barrier layer are repeatedly stacked. The emitted light is moved toward the shorter wavelength as the Al composition of the well layer increases, and when In increases, the emission wavelength can be controlled by moving to the longer wavelength. Therefore, the composition of the light emitting layer 4 is suitably selected according to the light emission wavelength made to emit light by a nitride type semiconductor light emitting element.

Reference numeral 5 is a p-type nitride semiconductor layer. The p-type nitride-based semiconductor layer is composed of Al _x Ga _{1 -x} N doped with carbon according to the present invention. According to the manufacturing method of the present invention, the aluminum composition ratio of Al _x Ga _{1- x} N may be increased by 77%. When the aluminum composition ratio is increased to 77%, the p-type cladding layer having a wider band gap than the band gap of the light emitting layer 4 can be easily realized. The thickness of the p-type nitride semiconductor layer 5 is preferably 0.1 µm or more and 3 µm or less.

Further, when the p-type nitride semiconductor layer 5 is composed of carbon-doped Al _x Ga _{1- x} N according to the present invention, the p-type nitride semiconductor layer 5 is composed of GaN or AlGaN having a p-type by doping Mg. Excellent IV characteristics. Therefore, when the carbon-doped Al _x Ga _{1- x} N according to the present invention is used for the p-type nitride based semiconductor layer 5, the current diffusion layer or the p-type electrode is appropriately provided between the p-type nitride based semiconductor layer 5 and the p-type electrode. Although a contact layer may be provided, the p-type electrode can be directly formed on the p-type nitride based semiconductor layer 5 without providing a current diffusion layer or a contact layer. The p-type nitride semiconductor layer 5 made of carbon-doped Al _x Ga _{1 - x} N is intended to easily realize schottky contact with the p-type electrode by adjusting the effective ionization acceptor density.

6 is a p-type electrode. The p-type electrode 6 can be composed of, for example, a single layer film containing any one of Al, Pt, Ru, Ag, Ti, Au, and Ni, a multilayer film or an alloy composed of two or more layers.

Reference numeral 7 is an n-type electrode. The n-type electrode 7 is formed on the exposed surface where the n-type nitride semiconductor layer is exposed by etching a portion of the p-type nitride semiconductor layer 5, the light emitting layer 4, and the n-type nitride semiconductor layer. The n-type electrode 7 can be composed of two or more multilayer films composed of any one of Cr, Ti, Au, Al, and Ni.

20 corresponds to an example of the layer structure of the nitride semiconductor light emitting device, and thus the present invention is not limited thereto.

21 is a conceptual diagram illustrating another example of a layer structure of a nitride based semiconductor light emitting device using carbon doped Al _x Ga _1-x N according to the present invention. The same reference numerals are used for parts substantially the same as or equivalent to those in FIG.

A method of manufacturing the nitride semiconductor light emitting device of FIG. 21 is as follows. The buffer layer 2 is laminated on the substrate 1, and the n-type nitride semiconductor layer 3, the light emitting layer 4, and the p-type nitride semiconductor layer 5 are sequentially stacked thereon. In addition, a reflective electrode containing a metal such as Ag to reflect light toward the opposite side of the light extraction surface among the light emitted from the active layer 4 on the p-type nitride based semiconductor layer 5 to improve light extraction efficiency. (8) is laminated. The reflective electrode 8 can also function as a p-type electrode. Between the reflective electrode 8 and the p-type nitride based semiconductor layer 5, a composition layer exhibiting a function of preventing the diffusion of the reflective electrode 8 component can be inserted.

On the reflective electrode 8, for example, a conductive substrate 10 containing silicon or the like prepared separately is bonded through an adhesive layer 9 containing Au or the like. Thereafter, the substrate 1 is removed by polishing or etching. At this time, all or part of the buffer layer 2 together with the substrate 1 can likewise be removed by polishing or etching.

The n type electrode 7 is formed in the board | substrate 1 or the surface in which all or one part of the board | substrate 1 and the buffer layer 2 were removed. As the n-type electrode 7, a transparent electrode such as ITO may be used.

As described above, the nitride semiconductor light emitting device having the structure of FIG. 21 was described. In this embodiment as well, the p-type cladding layer having a wider band gap than the band gap of the light emitting layer can be realized by using Al x Ga 1-x N doped with carbon according to the present invention as the p-type nitride based semiconductor layer 5, and the sheet resistance is high. Since it is low, it is not necessary to naturally insert a contact layer or the like for ohmic contact between the p-type nitride based semiconductor layer 5 and the electrode.

As described above, according to the present invention, a p-type nitride semiconductor layer by carbon doping which has been difficult until now can be stably manufactured. That is, since the carbon-doped nitride-based semiconductor layer is a material which is also n-type in terms of carbon properties, it is difficult to realize a p-type stably in carbon doping, but according to the manufacturing method of the present invention, a carbon-doped p-type nitride-based semiconductor stably It is possible to make a layer.

In addition, since impurity introduction is realized by carbon doping, it is possible to reduce resistance unlike Mg doping. In addition, when the carbon doped nitride semiconductor layer is made of AlGaN, a p-type cladding layer having a band gap larger than that of the light emitting layer made of InGaN or the like can be realized. Therefore, according to the present invention, a nitride-based semiconductor light emitting device having high luminous efficiency can be manufactured without inserting a contact layer or the like between the p-type nitride-based semiconductor layer and the electrode.

In addition, the p-type nitride semiconductor layer including Al _x Ga _{1 - x} N doped with carbon according to the present invention has a current of 20 mA for a bias voltage of about 9 V, for example, as shown in FIG. Flow. Therefore, the p-type nitride semiconductor layer containing Al _x Ga _{1 - x} N doped with carbon according to the present invention can realize low resistance by controlling the effective ionization acceptor density. Therefore, the p-type nitride-based semiconductor layer including Al _x Ga _{1 - x} N doped with carbon according to the present invention can remove the p-type electrode away from the active layer to eliminate light absorption loss. In addition, the p-type nitride-based semiconductor layer containing Al _x Ga _{1 - x} N doped with carbon has a thickness of three times the oscillation wavelength (for example, about the thickness of the p-type nitride-based semiconductor layer in order to lower the oscillation threshold. 3 micrometers) can be applied to a semiconductor laser.

(Explanation of the sign)

1 board

2 buffer layer

3 n-type nitride semiconductor layer

4 light emitting layer

5p type nitride semiconductor layer

6 p-type electrode

7 n-type electrode

11 Monocrystalline Substrate

12 p-type AlGaN semiconductor layer

Claims (24)

1. Group III source is supplied for a predetermined time T ₁ ,

   After the start of supplying the group III source, after a predetermined time t _1, the Group V source containing the carbon source material is supplied for a predetermined time T ₂ (wherein t ₁ + T ₂ > T ₁ ),

   Supplying the Group III source gas and supplying the Group V source after a predetermined time t ₂ (where t ₁ + T ₂ -t ₂ > T ₁ ) has elapsed after the Group V source supply started. Repeatedly, the Al _x Ga _{1 - x} N semiconductor layer (0 &lt; 0 &lt; 0 &gt;) at a growth temperature of 1190 deg. C to 1370 deg. C or a growth temperature at which the substrate temperature becomes 1070 deg. C to 1250 deg. forming x ≤ 1),

   A method of manufacturing a p-type nitride semiconductor layer in which carbon is doped to a nitrogen site of the semiconductor layer.
2. The method according to claim 1,

   The single crystal substrate is a method of manufacturing a p-type nitride-based semiconductor layer is a sapphire substrate with a main surface has an offset angle of ± 0.1% range with respect to (0001) C surface.
3. The method according to claim 1 or 2,

   And the carbon source material is carbon tetrabromide (CBr ₄ ).
4. The method according to claim 1,

   The group V source is a method of manufacturing a p-type nitride-based semiconductor layer comprising a magnesium source material.
5. The method according to claim 1,

   The aluminum content is 5mol% ~ 100mol% method for producing a p-type nitride-based semiconductor layer.
6. The method according to claim 1,

   Supply time without setting the overlap between T _2, the supply time interval between T ₂ of the group V source and the supply time T ₁ of the group III source of supply time of the group III source and T ₁ wherein the group V source gas, The manufacturing method of the p-type nitride-type semiconductor layer which is 0 second or more and 2 second or less.
7. In the III-V nitride-based semiconductor layer growth method of growing a III-V nitride-based semiconductor layer using a MOVPE method directly on the substrate or through a single or a plurality of intervening layers,

   The atomic layer of the group III atoms and carbon by supplying the group III atomic source gas of Al _x Ga _1-x N (0 <x ≤ 1), the group V atomic source gas, and the carbon source gas as p-type impurities in the reaction tube Alternately growing an atomic layer of doped Group V atoms,

   The substrate is composed of any one of a sapphire substrate, silicon substrate, silicon carbide substrate, gallium nitride substrate, aluminum nitride substrate, the main surface group III-V having an offset angle in the range of ± 0.1% with respect to the C surface and the equivalent crystal surface A growth method of a nitride based semiconductor layer.
8. In the growth method of a III-V nitride-based semiconductor layer to grow a III-V nitride-based semiconductor layer using a MOVPE method directly on the substrate, or through a single or a plurality of intervening layers,

   After supplying the Group III atomic source gas of Al _x Ga _1-x N (0 <x ≤ 1) for a predetermined time into the reaction tube, the process of supplying the Group V atomic source gas for a predetermined time is alternately performed, Alternately growing a group atomic atomic layer and a group V atomic atomic layer,

   A method of growing a III-V nitride semiconductor layer in which carbon is introduced into an atomic layer of the Group V atoms by supplying the Group V atomic source gas for a predetermined period of time and also supplying a carbon source gas as a p-type impurity.
9. The method according to claim 8,

   The method of growing a group III-V nitride-based semiconductor layer further comprising supplying the Mg source gas while supplying the group V atomic source gas for the predetermined time.
10. The method according to claim 8,

    And supplying the source gas of Mg continuously during the step of supplying the Group III atomic source gas of Al _x Ga _{1- x} N for a predetermined time, and then supplying the Group V atomic source gas for a predetermined time. A growth method of a nitride based semiconductor layer.
11. The method according to claim 8,

    And supplying a source gas of Mg while supplying the Group V atomic source gas for the predetermined time.
12. The method according to claim 8,

    The substrate is a growth method of a III-V group nitride semiconductor layer composed of any one of a sapphire substrate, silicon substrate, silicon carbide substrate, gallium nitride substrate, aluminum nitride substrate.
13. The method according to any one of claims 8 to 12,

    And a main surface of the substrate having an offset angle in a range of ± 0.1% with respect to a C surface and an equivalent crystal surface thereof.
14. The method according to claim 7,

    The method of growing a group III-V nitride semiconductor layer, wherein the group III-V nitride semiconductor layer has a thickness of 0.1 µm or more and 3 µm or less.
15. The method according to claim 8,

    The method of growing a group III-V nitride semiconductor layer, wherein the group III-V nitride semiconductor layer has a thickness of 0.1 µm or more and 3 µm or less.
16. Group III-V nitride and semiconductor layers of Al x Ga 1-x N are simultaneously supplied into the reaction tube to grow a group III-V nitride semiconductor layer directly on the substrate or through one or more intervening layers. In the growth method of a group nitride semiconductor layer,

    including supplying a carbon source gas as a p-type impurity,

    A growth method of a III-V nitride-based semiconductor layer in which the ratio of the group V atomic source gas and the group III atomic source gas is 5 or more and 600 or less.
17. The method according to claim 16,

    The substrate is composed of any one of a sapphire substrate, silicon substrate, silicon carbide substrate, gallium nitride substrate, aluminum nitride substrate, the main surface group III-V having an offset angle in the range of ± 0.1% with respect to the C surface and the equivalent crystal surface A growth method of a nitride based semiconductor layer.
18. a lamination of an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer,

    The p-type nitride semiconductor layer is composed of any one of a sapphire substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and an aluminum nitride substrate, and a main surface thereof has an offset angle in a range of ± 0.1% with respect to the C surface and its equivalent crystal surface. A source gas of carbon as a group III atomic source gas of Al _x Ga _{1 - x} N (0 <x ≤ 1), a group V atomic source gas, and a p-type impurity directly on the substrate having, or on a single or a plurality of intervening layers The nitride-based semiconductor light emitting device in which an atomic layer of group III atoms and an atomic layer of carbon-doped group V atoms are alternately grown.
19. a lamination of an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer,

    The p-type nitride semiconductor layer is formed by alternately growing an atomic layer of group III atoms and an atomic layer of group V atoms by alternately supplying a group III atomic source gas and a group V atomic source gas in a reaction tube, respectively. A nitride-based semiconductor light-emitting device in which a layer is introduced and carbon is introduced by supplying a carbon source gas at a time of supplying the group V atom source gas.
20. The method according to claim 19,

    The p-type nitride semiconductor layer is Al _x Ga _{1 - x} N (0 <x ≤ 1) nitride-based semiconductor light emitting device.
21. The method according to claim 18,

    The nitride-based semiconductor light emitting device further comprising a p-type electrode formed on the p-type nitride-based semiconductor layer.
22. The method according to claim 19 or 20,

    The nitride-based semiconductor light emitting device further comprising a p-type electrode formed on the p-type nitride-based semiconductor layer.
23. In a method of growing a III-V nitride semiconductor layer, in which a p-type nitride semiconductor layer is grown directly on a substrate or through one or a plurality of intervening layers, using a MOVPE method to grow a III-V nitride-based semiconductor layer. After supplying the Group III atomic source gas of Al _x Ga _1-x N to the tube for a predetermined time, the process of supplying the Group V atomic source gas for a predetermined time is alternately performed to make the atomic layer of the Group III atom and the atoms of the Group V atom The layer III-V nitride semiconductor layer in which carbon is introduced into the atomic layer of the group V atoms by growing layers alternately and supplying the group V atom source gas for a predetermined time and also supplying a carbon source gas as a p-type impurity. Including semiconductor laser.
24. The method according to claim 23,

    And a layer thickness of the p-type nitride semiconductor layer is 3 µm.

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