WO2010100689A1 - 窒化ガリウム系化合物半導体の製造方法、および半導体発光素子 - Google Patents
窒化ガリウム系化合物半導体の製造方法、および半導体発光素子 Download PDFInfo
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- WO2010100689A1 WO2010100689A1 PCT/JP2009/005526 JP2009005526W WO2010100689A1 WO 2010100689 A1 WO2010100689 A1 WO 2010100689A1 JP 2009005526 W JP2009005526 W JP 2009005526W WO 2010100689 A1 WO2010100689 A1 WO 2010100689A1
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Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
- C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
- C23C16/301—AIII BV compounds, where A is Al, Ga, In or Tl and B is N, P, As, Sb or Bi
- C23C16/303—Nitrides
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
- C30B25/02—Epitaxial-layer growth
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/40—AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
- C30B29/403—AIII-nitrides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0062—Processes for devices with an active region comprising only III-V compounds
- H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
- H01L33/007—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound comprising nitride compounds
Definitions
- the present invention relates to a method for manufacturing a gallium nitride compound semiconductor and a semiconductor light emitting device manufactured by the manufacturing method.
- a nitride semiconductor having nitrogen (N) as a group V element is considered promising as a material for a short-wavelength light-emitting element because of its band gap.
- gallium nitride compound semiconductors GaN-based semiconductors
- LEDs blue light-emitting diodes
- semiconductor lasers made of GaN-based semiconductors have been put into practical use.
- FIG. 1 schematically shows a unit cell of GaN.
- Al a Ga b In C N ( 0 ⁇ a, b, c ⁇ 1, a + b + c 1) semiconductor crystal, some of the Ga shown in FIG. 1 may be replaced by Al and / or In.
- FIG. 2 shows four basic vectors a 1 , a 2 , a 3 , and c that are generally used to represent the surface of the wurtzite crystal structure in the 4-index notation (hexagonal crystal index).
- the basic vector c extends in the [0001] direction, and this direction is called “c-axis”.
- a plane perpendicular to the c-axis is called “c-plane” or “(0001) plane”.
- c-axis” and “c-plane” may be referred to as “C-axis” and “C-plane”, respectively.
- FIG. 3 there are typical crystal plane orientations other than the c-plane.
- 3 (a) is the (0001) plane
- FIG. 3 (b) is the (10-10) plane
- FIG. 3 (c) is the (11-20) plane
- FIG. 3 (d) is the (10-12) plane.
- “-” attached to the left of the number in parentheses representing the Miller index means “bar”.
- the (0001) plane, (10-10) plane, (11-20) plane, and (10-12) plane are c-plane, m-plane, a-plane, and plane, respectively.
- the m-plane and a-plane are “nonpolar planes” parallel to the c-axis, while the r-plane is a “semipolar plane”.
- the m-plane is a general term for the (10-10) plane, the (-1010) plane, the (1-100) plane, the (-1100) plane, the (01-10) plane, and the (0-110) plane.
- the X plane may be referred to as a “growth plane”.
- a semiconductor layer formed by X-plane growth may be referred to as an “X-plane semiconductor layer”.
- gallium nitride-based compound semiconductors on nonpolar surfaces such as m-plane and a-plane, or semipolar planes such as r-plane. If a nonpolar plane can be selected as the growth plane, polarization does not occur in the layer thickness direction (crystal growth direction) of the light-emitting portion, so that no quantum confined Stark effect occurs, and a potentially high-efficiency light-emitting element can be manufactured. Even when the semipolar plane is selected as the growth plane, the contribution of the quantum confined Stark effect can be greatly reduced.
- FIG. 4A schematically shows a crystal structure in a cross section (cross section perpendicular to the substrate surface) of the nitride-based semiconductor whose surface is m-plane. Since Ga atoms and nitrogen atoms exist on the same atomic plane parallel to the m-plane, no polarization occurs in the direction perpendicular to the m-plane. The added In and Al are located at the Ga site and replace Ga. Even if at least part of Ga is substituted with In or Al, no polarization occurs in the direction perpendicular to the m-plane.
- FIG. 4B schematically shows the crystal structure of a nitride semiconductor cross section (cross section perpendicular to the substrate surface) having a c-plane surface.
- Ga atoms and nitrogen atoms do not exist on the same atomic plane parallel to the c-plane.
- polarization occurs in a direction perpendicular to the c-plane.
- the c-plane GaN-based substrate is a general substrate for growing a GaN-based semiconductor crystal. Since the positions of the Ga (or In) atomic layer and the nitrogen atomic layer parallel to the c-plane are slightly shifted in the c-axis direction, polarization is formed along the c-axis direction.
- a light emitting device having a light emitting layer formed on a non-polar m-plane has the advantage that the quantum confined Stark effect does not occur, but the crystal growth is problematic compared to conventional c-plane growth. There are several.
- the band gap of the In x Ga 1-x N crystal changes depending on the In composition x.
- the larger the In composition x the smaller the In x Ga 1-x N band gap, and the closer to the band gap of the InN crystal.
- the emission wavelength increases. If the In composition is increased to 15% or more, long wavelength light emission such as blue or green can be obtained by the gallium nitride compound semiconductor light emitting device.
- the growth temperature of GaN containing no In is usually set to 1000 ° C. or higher.
- In x Ga 1-x N since In easily evaporates, it is necessary to lower the growth temperature sufficiently below 1000 ° C.
- the In incorporation efficiency is lower than that in the case of c-plane growth. For this reason, it is extremely difficult to realize an m-plane device capable of emitting light of a long wavelength.
- FIG. 5 is a graph showing the relationship between the emission wavelength of the InGaN layer grown by the MOCVD method and the growth temperature.
- the graph shows the emission wavelength of an InGaN layer formed by c-plane growth (hereinafter referred to as “c-plane InGaN layer”) and the InGaN layer formed by m-plane growth (hereinafter referred to as “m-plane InGaN layer”).
- the emission wavelength is shown.
- the horizontal axis of the graph is the growth temperature, and the vertical axis is the peak wavelength.
- the peak wavelength of light emission obtained from the c-plane InGaN layer is indicated by ⁇
- the peak wavelength of light emission obtained from the m-plane InGaN layer is indicated by ⁇ .
- This graph was created based on the results of experiments by the present inventors.
- the supply conditions of the source gas supplied to the reaction chamber of the MOCVD apparatus during the growth of the InGaN layer are as follows.
- sccm standard cc / minute
- slm standard liter / minute
- sccm volume indicated by the volume of the raw material gas supplied to the reaction chamber per minute (value converted to a volume at 0 ° C. and 1 atm).
- Flow rate The unit of sccm volume is [cc]
- the unit of slm volume is [liter].
- ⁇ mol / min is a molar supply flow rate indicated by the molar amount of the raw material gas supplied to the reaction chamber every minute.
- TMG is trimethylgallium (Ga source gas)
- TMI is trimethylindium (In source gas).
- NH 3 is a source gas of N (nitrogen).
- the emission wavelength increases as the growth temperature decreases. This means that the lower the growth temperature, the higher the In incorporation rate, and the accompanying increase in the In composition x in the In x Ga 1-x N crystal.
- the growth temperature dependence of the emission wavelength is linear, and the absolute value of the slope is relatively small in m-plane growth.
- the emission wavelength of the m-plane InGaN layer is much shorter than the emission wavelength of the c-plane InGaN layer at the same growth temperature.
- the In incorporation efficiency is lower in the m-plane growth than in the c-plane growth.
- the crystallinity of the m-plane InGaN layer is significantly lowered due to an increase in crystal defects and vacancies in the obtained m-plane InGaN layer.
- the decrease in the growth temperature also causes a decrease in the decomposition efficiency of NH 3 in the reaction chamber. For this reason, it is not realistic to perform m-plane growth at an extremely low temperature below 700 ° C. from the viewpoint of the characteristics of the light emitting element.
- the present invention has been made to solve the above-described problems, and its object is to manufacture a gallium nitride-based compound semiconductor with improved In incorporation efficiency into a crystal when an InGaN layer is formed by m-plane growth. It is to provide a method.
- a method for producing a gallium nitride compound semiconductor according to the present invention is a method for producing a gallium nitride compound semiconductor in which an m-plane InGaN layer having an emission peak wavelength of 500 nm or more is grown by metal organic chemical vapor deposition, Step (A) for heating the substrate, and a gas containing In source gas, Ga source gas, and N source gas are supplied into the reaction chamber, and In x Ga 1-x N is grown at a growth temperature of 700 ° C. to 775 ° C.
- Another method of manufacturing a gallium nitride compound semiconductor according to the present invention is a method of manufacturing a gallium nitride compound semiconductor in which an m-plane InGaN layer having an emission peak wavelength in a range from 450 nm to 500 nm is grown by metal organic chemical vapor deposition.
- a gas containing In source gas, Ga source gas, and N source gas is supplied into the reaction chamber at a growth temperature of 775 ° C. to 785 ° C.
- Another method for producing a gallium nitride compound semiconductor according to the present invention is a method for producing a gallium nitride compound semiconductor in which an m-plane InGaN layer having an emission peak wavelength in the range of 425 nm to 475 nm is grown by metal organic vapor phase epitaxy.
- a gas containing In source gas, Ga source gas, and N source gas is supplied into the reaction chamber at a growth temperature of 770 ° C. to 790 ° C.
- Another method for producing a gallium nitride compound semiconductor according to the present invention is a method for producing a gallium nitride compound semiconductor in which an m-plane InGaN layer having an emission peak wavelength in the range of 425 nm to 475 nm is grown by metal organic vapor phase epitaxy.
- a gas containing In source gas, Ga source gas, and N source gas is supplied into the reaction chamber at a growth temperature of 770 ° C. to 790 ° C.
- the method for manufacturing a semiconductor light emitting device includes a step of preparing a substrate and a step of forming a semiconductor multilayer structure having a light emitting layer on the substrate, wherein the step of forming the semiconductor multilayer structure is any of the above.
- the light emitting layer has a multiple quantum well structure
- the m-plane InGaN layer is a well layer included in the multiple quantum well structure.
- a preferred embodiment includes a step of removing the substrate.
- a semiconductor light-emitting device of the present invention includes a light-emitting layer including an m-plane InGaN layer formed by the method for manufacturing a gallium nitride-based compound semiconductor according to any one of the above, and an electrode for supplying a charge to the light-emitting layer. .
- the present invention it is possible to enhance the incorporation efficiency into In x Ga 1-x N ( 0 ⁇ x ⁇ 1) of In atoms for forming the layer in the crystal by the m-plane growth, the m-plane In x Ga It is possible to improve the In composition (x) of the 1-x N layer. Therefore, according to the present invention, when forming In x Ga 1-x N that functions as a light emitting layer of a light emitting element, blue or red, which has been difficult to achieve with conventional m-plane In x Ga 1-x N layers, is achieved. Long wavelength light emission such as green can be realized, and a high-efficiency long wavelength light emitting LED without the contribution of the quantum confined Stark effect can be stably produced.
- FIG. 4 is a perspective view showing basic translation vectors a 1 , a 2 , a 3 , and c of a wurtzite crystal structure.
- (A) to (d) are schematic views showing typical crystal plane orientations of a hexagonal wurtzite structure.
- (A) is a figure which shows the crystal structure of m plane
- (b) is a figure which shows the crystal structure of c plane. It is a graph which shows the difference in the growth temperature dependence of the light emission wavelength from an m-plane growth InGaN layer and a c-plane growth InGaN layer.
- the step (A) of heating the substrate in the reaction chamber of the MOCVD apparatus the source gas is supplied into the reaction chamber, and m consisting of In x Ga 1-x N (0 ⁇ x ⁇ 1).
- a step (B) of growing a planar InGaN layer on the substrate In step (B), a gas containing an In source gas, a Ga source gas, and an N source gas is supplied into the reaction chamber, and the value determined in accordance with the emission wavelength peak aimed at the growth rate of the m-plane InGaN layer Set to.
- the growth rate when growing an m-plane InGaN layer having an emission wavelength peak of 500 nm or more, the growth rate is set to 4.5 nm / min or more.
- the growth rate is set in the range from 3 nm / min to 10 nm / min.
- the growth rate is set to 8 nm / min or more, or in the range from 4 nm / min to 5 nm / min. Set to.
- the growth temperature is also adjusted according to the target emission wavelength peak.
- Ga supply ratio means that during the growth of an In x Ga 1-x N (0 ⁇ x ⁇ 1) layer, each source gas of Ga and In, which is a group III atom supplied into the reaction chamber, for 1 minute It is defined based on the respective molar feed flow rate (mol / min).
- the “Ga supply ratio” in this specification represents the ratio of the supply rate of the Ga source gas to the total supply rate of the In source gas and the Ga source gas as a percentage. Accordingly, when the molar supply flow rate (mol / min) of Ga source gas per minute is [Ga source gas] and the molar supply flow rate (mol / min) of In source gas per minute is [In source gas], Ga The supply ratio is expressed by the following equation.
- the In source gas is, for example, trimethylindium (TMI)
- the Ga source gas is, for example, trimethylgallium (TMG) or triethylgallium (TEG).
- the In supply ratio is expressed by the following equation, and the sum of the Ga supply ratio and the In supply ratio is 100%.
- the “supply rate” of the source gas is simply referred to as “supply amount”
- the supply rate of the Ga source gas is simply “Ga supply amount”
- the In source gas eg, TMI. Is simply referred to as “In supply amount”.
- the In x Ga 1-x N (0 ⁇ x ⁇ 1) layer is formed by c-plane growth at a growth temperature as high as possible in order to suppress deterioration of crystallinity and deterioration of NH 3 decomposition efficiency. It is customary to do so. In that case, since In which is easily evaporated does not easily enter the crystal, it is necessary to increase the In supply ratio as much as possible. For this reason, in normal c-plane growth, the In supply ratio is set to about 90% or more.
- the In incorporation efficiency is lower than that in the c-plane growth.
- the In supply ratio already at a level as high as 90% is only increased by a few percent, and the effect cannot be expected.
- increasing the emission peak wavelength by increasing the In supply amount had little effect. Therefore, it is very difficult to realize In x Ga 1-x N that emits light in blue (about 450 nm) or green (more than 500 nm) by m-plane growth.
- the present inventor found a phenomenon that the In incorporation efficiency is increased by increasing the supply amount of Ga, not In, and decreasing the In supply ratio, thereby completing the present invention. Hereinafter, this phenomenon will be described.
- the present inventor improves the In incorporation efficiency even if the In supply ratio decreases if the Ga supply amount is increased within an appropriate range. It came to discover the new fact of doing. Increasing the amount of Ga supply is equivalent to increasing the growth rate of the In x Ga 1-x N (0 ⁇ x ⁇ 1) layer. As will be described later, there is a linear relationship between the Ga supply amount and the growth rate. In addition, fixing the supply amount of the In source gas and selectively increasing only the Ga supply amount leads to a decrease in the ratio of the In source gas in the group III atom source gas, that is, the In supply ratio. means. The phenomenon that the In incorporation efficiency is improved by the decrease of the In supply ratio is very interesting.
- the growth rate of the In x Ga 1-x N layer used in the light emitting portion of the light emitting element is often set to about 1 to 2 nm / min.
- the growth rate is increased to a significantly higher value (typically 4.5 nm / min or more) than the conventional value.
- FIG. 6 shows that the growth rate of the In x Ga 1-x N layer is increased from 1 nm / min to 7 nm / min by increasing the Ga supply rate while maintaining the growth temperature at 780 ° C. and keeping the In supply rate constant. It shows the spectral change of the emission obtained from the In x Ga 1-x N layer when it is raised.
- the horizontal axis of the graph of FIG. 6 is the wavelength of light emission (unit: nm) obtained from the In x Ga 1-x N layer, and the vertical axis is the intensity of light emission (arbitrary unit).
- the solid line in the graph is an emission spectrum obtained from a sample with a growth rate of 1 nm / min, and the broken line in the graph is an emission spectrum obtained from a sample with a growth rate of 7 nm / min.
- the emission wavelength was increased from about 400 nm emission to 485 nm emission by greatly increasing the Ga supply amount. That is, it has been clarified that the “growth rate” controlled by the Ga supply amount is a very effective factor for increasing the In composition of the m-plane In x Ga 1-x N layer.
- the growth rate of the m-plane In x Ga 1-x N layer can also be expressed as “growth rate” or “deposition rate”. In this specification, the unit of the growth rate is handled uniformly by nm / min.
- Group III atoms of the In x Ga 1-x N layer are composed of Ga and In.
- the growth rate of the In x Ga 1-x N layer is determined by the supply amount of the group III atom.
- the amount of N is set to 10,000 in terms of the V / III ratio.
- This V / III ratio is preferably 1000 or more for crystal growth of InGaN.
- In is an atom that is much easier to evaporate than Ga. Therefore, the growth rate of the entire crystal layer is substantially determined by the supply amount of TMG or TEG that is a Ga source gas. The In other words, there is almost no contribution of the amount of In supply to the growth rate.
- FIG. 7 is a graph showing the relationship between the growth rate of the m-plane In x Ga 1-x N layer and the TMG supply amount when TMG is used as the Ga supply source.
- the horizontal axis of the graph is the TMG supply amount
- the vertical axis is the growth rate of the m-plane In x Ga 1-x N layer.
- the growth temperature is 770 ° C. to 790 ° C.
- the supply amount of TMI is 380 sccm (148.7 ⁇ mol / min). Note that the In supply amount hardly contributes to the growth rate, and the tendency shown in FIG. 7 is not limited to the case where the In supply amount is 380 sccm (148.7 ⁇ mol / min).
- FIG. 7 shows that the growth rate of the m-plane In x Ga 1-x N layer can be easily controlled by adjusting the Ga supply amount. Since the data in FIG. 7 is obtained with the In supply amount fixed at a predetermined value, an increase in the Ga supply amount means a decrease in the In supply ratio.
- the reason why the In incorporation efficiency increases when the growth rate of the InGaN layer, that is, the Ga supply amount is increased, can be shown based on the behavior of Ga and In based on the step flow growth of the crystal.
- the knowledge obtained by the present inventor will be described regarding the relationship between the Ga supply amount and the In incorporation efficiency in the growth of the m-plane In x Ga 1-x N layer.
- the ideal surface of a crystal to be grown is not limited to gallium nitride compound semiconductors.
- the ideal surface of a crystal has a relatively wide flat area called a terrace and a step called a step having a height equivalent to a monoatomic layer. It is repeated repeatedly and is typically configured to look like a staircase.
- FIG. 8 is a perspective view schematically showing the state of the crystal surface during crystal growth. In FIG. 8, one step extending in the x-axis direction and the terrace are illustrated. There are many steps and terraces on the actual crystal surface. O in the figure schematically shows atoms of Ga and In.
- Atoms such as Ga and In that have been incident on the surface (growth surface) of the growing crystal have kinetic energy even if they are once adsorbed on the terrace, and thus move around by randomly diffusing on the terrace. In this state, it cannot be said that the atoms are taken into the crystal (solidified). This is because atoms may evaporate again into the gas phase during diffusion.
- atoms that can reach the step by chance can be regarded as having settled and solidified after stopping diffusion. This is because there are more dangling bonds at the step position than on the terrace where there is nothing, so that once the atoms reach there, the number of bonds increases, and a stable state can be settled. In other words, the step serves as an atom intake, but conversely, the atom cannot be solidified unless it reaches the step position.
- ⁇ Steps advance as atoms continue to diffuse into the step position and continue to be taken into the crystal. By repeating this, crystal growth of each single layer is realized. This is called “step flow growth” of crystals.
- FIG. 9 is a cross-sectional TEM photograph of the m-plane InGaN layer. It can be seen that there are many steps on the growth surface of the m-plane InGaN layer. For this reason, it is considered that the above-described principle of step flow growth is applicable to the m-plane growth of a gallium nitride compound semiconductor.
- the V / III ratio which is the supply ratio of group III atoms and group V atoms, to at least 10 3 or more. Therefore, the N atom, which is a group V atom, is sufficiently abundant as compared to the group III atom. Therefore, it can be considered that the N atom frequently repeats the bonding and detachment with the group III atom on the crystal surface of the growing gallium nitride compound semiconductor.
- the crystal growth rate is almost determined only by the amount of Ga supply, the crystal growth of the gallium nitride compound semiconductor is limited by the group III atoms, particularly the Ga atoms. You can say that. In other words, there are a sufficient number of N atoms on the crystal surface.
- the In composition can be determined if it can be estimated how much of the majority of Ga atoms will reach the step and be stably incorporated into the crystal. .
- the present inventor made one hypothesis by paying attention to the N atom at the step position. This hypothesis will be described with reference to FIG.
- FIG. 10A is a schematic cross-sectional view showing the crystal structure of m-plane gallium nitride at the atomic level
- FIG. 10B is a schematic top view thereof.
- a broken line in FIG. 10A represents a representative step, and FIG. 10B does not show atoms belonging to the lower terrace of the step.
- point A which is the step position.
- the N atom 201 at the position where it bonds with the group III atom that reaches the point A is in a very unstable state with only one bond with the group III atom already present in the crystal, but there was a surplus. Since one of the dangling bonds is bonded to the In atom that has reached point A, the stability is improved.
- the bond energy between In atoms and N atoms (1.93 eV) is smaller than the bond energy between Ga atoms and N atoms (2.24 eV). Therefore, if the Ga atom is the one that reaches the point A and is newly bonded to the N atom 201, the stability of the N atom 201 is greatly increased, so that the Ga atom will remain stably in place. However, if the atom reaching the point A is an In atom, even if it is newly bonded to this, the contribution to the increase in stability of the N atom 201 is low. Therefore, the unstable N atom 201 is detached again into the gas phase due to thermal fluctuation in a very short time. Then, it is considered that In atoms that have reached the point A are not taken into the crystal and are separated.
- N atom 201 is already in a state of having two bonds with Ga, so it exists stably on the spot. It is considered possible.
- the In atom reaches the point A in such a state, the N atom 201 has little problem in stability from the beginning, so it is unlikely to leave and evaporate into the gas phase.
- the possibility that the In atom that has reached point A stays in place stably increases.
- the N atom 201 also increases the stability, and as a result, the In atom can also remain in place stably. It can be said.
- FIG. 11 shows the emission wavelength and growth rate from the m-plane In x Ga 1-x N layer formed at different growth temperatures under the condition that the In supply rate is constant at 380 sccm (148.7 ⁇ mol / min), and Ga It is a graph which shows the relationship with a supply ratio.
- the vertical axis of the graph is the peak wavelength of light emission.
- the horizontal axis (lower side) of the graph represents the Ga supply ratio when the In supply amount is fixed at 380 sccm (148.7 ⁇ mol / min).
- the horizontal axis (upper side) of the graph represents the growth rate of the In x Ga 1-x N layer.
- the relationship between the growth rate (upper horizontal axis) and the Ga supply ratio (lower horizontal axis) will be described.
- the Ga supply ratio corresponds to 11%.
- This relationship is established only when the In supply amount is set to 380 sccm (148.7 ⁇ mol / min). That is, when the In supply amount is set to another value, the Ga supply ratio does not become 11% even if the growth rate is 5 nm / min.
- the growth rate is not affected by the In supply amount and is determined from the Ga supply amount, so that the characteristics of the present invention can be expressed more clearly in comparison with the Ga supply ratio.
- the growth temperatures are 770 ° C., 780 ° C., 790 ° C., and 800 ° C.
- the emission peak wavelengths described in this specification including FIG. 11 are all obtained by performing PL (photoluminescence) measurement using a He—Cd laser of 325 nm as an excitation light source at room temperature. An almost equivalent emission peak wavelength can also be obtained by electroluminescence measurement.
- Tables 2 to 5 below show the relationship between the growth rate and peak wavelength shown in FIG. 11 for each growth temperature.
- the growth rate of the In x Ga 1-x N layer increases linearly with an increase in Ga supply amount.
- the peak wavelength of light emission increases with an increase in the growth rate (Ga supply ratio when the In supply amount is constant) at any temperature. It can be confirmed that there is a long range.
- Increasing the wavelength of light emission means increasing the In composition. Since the In supply amount is constant, an increase in the growth rate corresponds to a decrease in the In supply ratio, but it can be seen that the In incorporation efficiency increases as the In supply ratio decreases. This result shows that the above hypothesis is correct.
- the degree of wavelength increase that occurs as the growth rate increases depends on the growth temperature.
- the growth rate is 1 nm / min (Ga supply ratio is 3%)
- all of light emission at about 770 ° C., 780 ° C., and 790 ° C. is about 400 nm.
- the growth rate is 5 nm / min (Ga supply ratio is 11%)
- an emission wavelength of about 420 nm is obtained at a growth temperature of 790 ° C., but when the growth temperature is lowered to 770 ° C., the emission wavelength is increased to about 520 nm, Visible green on the naked eye.
- it is effective to lower the growth temperature.
- FIG. 12 is a graph showing the relationship between the solidification amount of each atom and the Ga supply amount obtained by simulation.
- the solidification amount of atoms represents the number of atoms that are absorbed and fixed at the growth surface step and taken into the crystal per unit time. Details of the calculation formula and calculation conditions used for executing this simulation will be described later.
- the horizontal axis of the graph in FIG. 12 represents the amount of Ga atoms incident on the growth surface (amount proportional to the amount of Ga supply).
- amount proportional to the amount of Ga supply In the calculation, only the Ga supply amount is increased in a state where the In supply amount (In atom incidence amount on the growth surface) is maintained constant (1 ⁇ 10 5 cm ⁇ 2 sec ⁇ 1 ). Since the In supply amount is kept constant, the In supply ratio inevitably decreases as the Ga supply amount increases.
- the left vertical axis represents the solidification amount (arbitrary unit) of each atom
- the right vertical axis represents the In composition.
- the In composition is the proportion of In among the group III atoms incorporated into the crystal (In composition x), and is indicated by ⁇ in the graph. Further, the number of In (solidified amount) taken into the crystal per unit time is indicated by ⁇ , and the number of Ga (solidified amount) is indicated by ⁇ .
- the In composition dramatically increases as the Ga supply amount increases. In this range, the In composition is sensitive to changes in the Ga supply amount.
- the Ga supply amount is a value indicated by an arrow in FIG. 12 (about 3000 cm ⁇ 2 This is because crystal growth is performed at a value lower than sec ⁇ 1 ).
- the result of FIG. 12 may be obtained by substituting a known physical property value of another material similar to gallium nitride or arbitrarily assuming a value that is not greatly deviated. Therefore, the result of FIG. 12 lacks reliability for strict quantitativeness, but is sufficiently reliable for bird's-eye view of qualitative trends.
- the emission wavelength tends to be the longest at a growth rate of 5 nm / min to 7 nm / min (Ga supply ratio is 11% to 15%). If the Ga supply amount is further increased to increase the growth rate (Ga supply ratio when the In supply amount is constant), the tendency to increase the wavelength will stagnate or conversely result in a shorter wavelength. This is a result supporting the tendency obtained by the calculation shown in FIG. Therefore, the growth rate effective for increasing the In composition (Ga supply ratio when the In supply amount is constant) has an appropriate range.
- the growth rate (In supply amount is set to increase the In composition). It can be seen that there is a growth temperature range in which the Ga supply ratio (when constant) is an effective factor. As is clear from FIG. 11, it is desirable to set the growth temperature to less than 800 ° C. (for example, 795 ° C. or less).
- the growth temperature is set to less than 780 ° C. (preferably in the range from 700 ° C. to 775 ° C.) and the growth rate is set to 4. It is desirable to deposit the InGaN layer by adjusting the supply of the group III material so as to be between 5 nm / min and 10 nm / min. In other words, when the In supply amount is set to 380 sccm (148.7 ⁇ mol / min), the InGaN layer can be deposited by adjusting the supply of the group III raw material so that the Ga supply ratio is within the range of 10% to 21%. desirable.
- a wavelength of 500 nm or more can be realized by setting the growth temperature to about 772 ° C. or less.
- a wavelength of 500 nm or more can be realized by setting the growth temperature to about 750 ° C. or less.
- the growth temperature is 770 ° C.
- a wavelength of 500 nm or more can be realized by changing the growth rate from 4.5 nm / min to 9 nm / min.
- the growth rate is kept at 3 nm / min while maintaining the growth temperature at around 780 ° C. (range from 775 ° C. to 785 ° C.). It is desirable to deposit the InGaN layer by adjusting the supply of the group III raw material so that it is between 10 and 10 nm / min. In other words, when the In supply amount is set to 380 sccm (148.7 ⁇ mol / min), the InGaN layer is deposited by adjusting the supply of the group III raw material so that the Ga supply ratio is between 7% and 21%. Is desirable.
- the growth temperature is maintained in the range from 770 ° C. to 790 ° C., and the growth rate is changed from 4 nm / min to 5 nm / min. It is desirable to deposit the InGaN layer while adjusting the supply of the group III raw material so that the time is 8 nm / min. In other words, when the In supply amount is set to 380 sccm (148.7 ⁇ mol / min), the supply of the group III raw material is adjusted so that the Ga supply ratio is between 9% and 11%, or 17% or more. It is desirable to deposit an InGaN layer.
- the wavelength is in the range of up to 500 nm, it is not intended to increase In incorporation, but is effective in improving the quality of InGaN crystals.
- High crystal quality means that there are few crystal defects, and thus high light emission characteristics (efficiency). Light is emitted at a low voltage.
- an m-plane In x Ga 1-x N (x ⁇ 0.45) crystal that emits light with a wavelength up to about 550 nm can be produced according to the present invention.
- the growth temperature is 730 to 740 ° C. (optimally 730 ° C.) and the growth rate is 6 nm / min to 8 nm / min (optimally 7 nm / min).
- the supply amount of In is 380 sccm (148.7 ⁇ mol / min).
- m-plane In x Ga 1-x N (x> 0.45) crystals that emit light with a wavelength longer than 550 nm is performed under conditions of a growth rate of 4.5 nm / min or more, which is judged to be optimum by the present invention.
- Samples prepared under conditions where the growth temperature is less than 700 ° C. often have a metallic color. Such a sample is considered to have increased non-radiative centers, and since the emission intensity is extremely low, it is difficult to observe a clear peak of wavelength.
- the thicker In x Ga 1-x N (0 ⁇ x ⁇ 1) well layer can be expected to improve efficiency. This is because the number of carriers that can be trapped in the In x Ga 1-x N layer can be increased.
- the thickness of the In x Ga 1-x N well layer formed by m-plane growth is preferably set in the range from 6 nm to 20 nm. Accordingly, it is preferable that the growth rate of the m-plane grown In x Ga 1-x N (0 ⁇ x ⁇ 1) layer is large, and the present invention is advantageous from the viewpoint of productivity efficiency.
- FIG. 13 shows the growth temperature 785 on the (11-20) a plane which is a nonpolar plane other than the (10-10) m plane and the (10-12) r plane typical as a semipolar plane.
- the emission wavelength spectra when an InGaN layer is deposited simultaneously with the m-plane under the conditions of ° C and a growth rate of 7 nm / min are shown.
- a peak value of about 470 nm is shown, but in other plane orientations, the wavelength reaches only 400 nm at most.
- This result shows that increasing the In composition of the InGaN layer according to the present invention is a very effective means in the (10-10) m plane, and the present invention can be said to be a peculiar method in the m plane.
- the present inventor has found that achieving high In composition of the InGaN layer in the m-plane, that is, increasing the wavelength, is extremely difficult to achieve unless the means according to the present invention is used.
- the substrate is not limited. Locations that appear metallic in color appear, and the emission spectrum cannot be observed at such locations.
- the portion where the substrate has a metallic color is less likely to appear in a wavelength region of less than about 500 nm when a longer wavelength is intended only by lowering the temperature, but the wavelength is longer than that. Tends to appear in a relatively wide area. This is considered to be because when the longer wavelength of 500 nm or more is intended only by lowering the temperature, the growth temperature typically falls below 700 ° C., and the decomposition efficiency of NH 3 is significantly reduced.
- an InGaN layer that emits light with a wavelength of 500 nm or more can be produced without lowering the temperature so much, such a failure does not occur. Therefore, it can be said that the present invention is almost indispensable for achieving an emission wavelength of 500 nm or more at a minimum from an InGaN layer deposited by m-plane growth.
- the In supply amount is fixed at 380 sccm (148.7 ⁇ mol / min), but the absolute value of the In supply amount is not important for the present invention. Since the In supply ratio is already sufficiently large, the contribution of the change in the In supply amount to the longer wavelength is extremely small.
- the essential part of the present invention is that when the Ga supply amount is increased to increase the growth rate of the InGaN layer, the In composition of the InGaN layer is improved despite the decrease of the In supply ratio.
- a substrate on which (10-10) m-plane gallium nitride (GaN) can be grown is used.
- the self-supporting substrate of gallium nitride itself that exposes the m-plane is most desirable, but it may be a silicon carbide (SiC) 4H, 6H structure with a close lattice constant that exposes the m-plane.
- the sapphire which exposed m surface similarly may be sufficient.
- a material different from the gallium nitride compound semiconductor is used for the substrate, it is necessary to insert an appropriate intermediate layer or buffer layer between the gallium nitride compound semiconductor layer deposited on the substrate.
- the actual m-plane need not be a plane that is completely parallel to the m-plane, and may be inclined by a slight angle (0 to ⁇ 1 °) from the m-plane.
- the deposition of a gallium nitride compound semiconductor including an In x Ga 1-x N (0 ⁇ x ⁇ 1) layer is performed by a MOCVD (Metal Organic Chemical Vapor Deposition) method.
- MOCVD Metal Organic Chemical Vapor Deposition
- the substrate 101 is washed with a buffered hydrofluoric acid solution (BHF), and then sufficiently washed with water and dried. After cleaning, the substrate 101 is placed in the reaction chamber of the MOCVD apparatus so as not to be exposed to air as much as possible. Thereafter, the substrate is heated to 850 ° C. while supplying ammonia (NH 3 ) as a nitrogen source, and the substrate surface is cleaned.
- BHF buffered hydrofluoric acid solution
- trimethylgallium (TMG) or triethylgallium (TEG) and further silane (SiH 4 ) are supplied, and the substrate is heated to about 1100 ° C. to deposit the n-GaN layer 102.
- Silane is a source gas that supplies silicon (Si), which is an n-type dopant.
- the supply of SiH 4 is stopped, the temperature of the substrate is lowered to less than 800 ° C., and the GaN barrier layer 103 is deposited. Further, supply of trimethylindium (TMI) is started to deposit an In x Ga 1-x N (0 ⁇ x ⁇ 1) well layer 104.
- TMI trimethylindium
- the GaN barrier layer 103 and the In x Ga 1-x N (0 ⁇ x ⁇ 1) well layer 104 are alternately deposited in three cycles or more to form a GaN / InGaN multiple quantum well light-emitting layer 105 serving as a light-emitting portion. .
- the reason why the number of periods is three or more is that the larger the number of In x Ga 1-x N (0 ⁇ x ⁇ 1) well layers 104, the larger the volume capable of capturing carriers contributing to luminescence recombination, and the device efficiency. This is because of the increase.
- the supply of TMI is stopped, the growth temperature is raised to 1000 ° C., and biscyclopentadienyl magnesium (Cp 2 Mg) is used as a raw material for Mg as a p-type dopant.
- Cp 2 Mg biscyclopentadienyl magnesium
- the substrate taken out of the reaction chamber is removed by using a technique such as photolithography to remove only predetermined regions of the p-GaN layer 106 and the GaN / InGaN multiple quantum well light-emitting layer 105 by using a technique such as etching.
- a part of 102 is expressed.
- an n-type electrode made of Ti / Al or the like is formed in the region where the n-GaN layer 102 is exposed.
- a p-type electrode made of Ni / Au or the like is formed in a predetermined region on the p-GaN layer 106.
- each of the n-type and p-type carriers can be injected, and a light-emitting element that emits light at a desired wavelength in the GaN / InGaN multiple quantum well light-emitting layer 105 manufactured by the manufacturing method according to the present invention. Can be produced.
- the In composition for realizing each wavelength is calculated as follows.
- the calculation result of the In composition varies depending on the physical properties such as the elastic constant and the film thickness of the well layer.
- the relationship between the emission wavelength to be realized and the In composition is not limited to the following example. 410 nm ⁇ In composition: 8-12% 430 nm ⁇ In composition: 13-17% 450 nm ⁇ In composition: 18-22% 475 nm ⁇ In composition: 24-28% 500 nm ⁇ In composition: 30% or more
- FIG. 15 is a diagram showing a cross-sectional configuration of the reaction chamber in the MOCVD apparatus used in the experiment of the present invention.
- the substrate 301 is accommodated in a counterbored portion of the quartz tray 302.
- the quartz tray 302 is placed on a carbon susceptor 303 in which a thermocouple 306 is embedded.
- the carbon susceptor 303 is installed inside the quartz flow channel 304 installed inside the water cooling jacket 305.
- the carbon susceptor 303 is heated by a RF induction heating method from a coil (not shown) surrounding the water cooling jacket 305.
- the substrate 301 is heated by heat conduction from the carbon susceptor 303.
- “Growth temperature” in this specification is a temperature measured by the thermocouple 306. This temperature is the temperature of the carbon susceptor 303 that is a direct heat source for the substrate 301. Since the carbon susceptor 303 is in thermal contact with the substrate 301, the temperature measured by the thermocouple 306 is considered to be substantially equal to the temperature of the substrate 301 during the light emitting layer growth process.
- the source gas and doping gas reach the vicinity of the substrate 301 from the outside of the reaction chamber through the flow path defined by the quartz flow channel.
- the method for producing a gallium nitride-based compound semiconductor according to the present invention can be suitably carried out using an apparatus other than the apparatus having the above-described configuration.
- substrate temperature are not limited to the method mentioned above.
- the present inventor decided to calculate the density distribution of Ga and In atoms that move around by diffusing on the terrace. By calculating the gradient at the step position of the obtained density distribution, it is possible to calculate the number of Ga and In atoms taken into the crystal at the step position per unit time.
- the terrace is parallel to the x-axis direction as shown in FIG.
- each step on the growth surface extends in one direction, and the above assumptions correspond well to the actual growth surface.
- the density of Ga atoms and the density of In atoms located on the terrace are both uniform in the x-axis direction and have a distribution only in the y-axis direction. be able to. Therefore, the density of Ga atoms on the terrace does not depend on the coordinate x, but is expressed by C Ga (y) which is a function of the coordinate y.
- the density of In atoms is expressed by C In (y), which is a function of the coordinate y.
- C Ga (y) and C In (y) can be simply expressed as C Ga and C In , respectively.
- C Ga and C In satisfy the following (Equation 3) diffusion equation and (Equation 4) diffusion equation, respectively.
- C Ga and C In can be obtained by solving these diffusion equations (differential equations) under predetermined boundary conditions.
- the upper suffix “Ga” of the symbol in the diffusion equation indicates that the symbol is a physical property value related to the Ga atom, and the upper subscript “In” indicates that the symbol is a physical property value related to the In atom.
- Ds is the diffusion coefficient of each atom
- F is the incident flux of each atom (flux of atoms entering the growth surface from the gas phase)
- ⁇ is the average residence time until each atom evaporates.
- the left side of the diffusion equation of (Equation 3) means an increase in density per unit time of Ga atoms at the position of coordinate y
- the left side of the diffusion equation of (Equation 4) is the unit time of In atoms at the position of coordinate y. Improves the density per hit.
- the atom exhibits a unique behavior different from that on the terrace.
- each parameter is as follows.
- ⁇ N sol Net solidification amount that each atom solidifies during time ⁇ t
- ⁇ 0 Debye frequency of each atom
- k B Boltzmann constant
- T environmental temperature
- ⁇ sol energy required for each atom to solidify
- ⁇ dif Energy required for each atom to diffuse to another position closest to the crystal surface
- Ga in the upper subscript indicates a physical property value related to the Ga atom
- the first term on the right side represents the amount of Ga atoms melted from the step
- the second term represents the amount of solidified Ga atoms in the step.
- boundary condition 2 of (Expression 6) as the simplest relationship among the boundary conditions in solving the diffusion equation (Expression 4) for In atoms.
- the upper subscript “In” indicates a physical property value related to In atoms.
- the first term on the right side of the boundary condition 2 represents the melting amount of In atoms from the step, and the second term represents the solidification amount of In atoms to the step. Similar to the Ga atom boundary condition 1, this is an equation representing a continuous relationship in which the net difference between solidification and melting is equal to the number of In atoms incorporated into the crystal through the step.
- the terrace sandwiched between adjacent steps is considered to be very wide at the atomic level, and even if the interaction between steps is omitted approximately, there is no problem in considering the essential mechanism of crystal growth.
- the diffusion equation (Equation 3) is solved for Ga atoms using boundary condition 1. Then, the density distribution C Ga of Ga atoms at the position of the coordinate y of the terrace is obtained. Accordingly, the Ga atom density C Ga step at the step position is also obtained.
- the diffusion equation is solved using boundary condition 2 for In atoms.
- the Ga atom density C Ga step at the already obtained step position is used.
- the density distribution C In of In atoms at the position of the coordinate y of the terrace is also obtained. Therefore, the gradient at the step position of the density distribution of Ga and In can be calculated.
- the density gradient at the step position represents the amount of change in density at the step position. This is the net quantity of atoms going to the step, that is, the quantity of each of Ga and In atoms incorporated into the crystal (solidification). Amount). The calculation results under the assumption that almost no melting from the Ga atom step occurs.
- the graph showing the solidification amount calculated in this way on the vertical axis and the flux of Ga atoms on the horizontal axis is the graph of FIG.
- the present invention is almost the only production method that can produce an InGaN layer having a high In composition on the m-plane of a gallium nitride compound semiconductor without a quantum confined Stark effect.
- a light emitting element capable of emitting light (green) having a wavelength exceeding 500 nm can be realized. For this reason, the wavelength region of the next-generation high-efficiency light-emitting element can be greatly expanded.
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Abstract
Description
図11を参照しながら、実験から得られたm面InxGa1-xN(0<x<1)層の発光波長とGa供給量(成長速度)との関係を説明する。なお、発光層は、GaNバリア層(3nm)とInxGa1-xN井戸層(7nm)を3周期で交互に堆積している。
図12は、シミュレーションによって求められた各原子の固化量とGa供給量との関係を示すグラフである。原子の固化量は、単位時間あたりに、成長面のステップに吸収・固定され、結晶に取り込まれていく原子の数を表している。このシミュレーションを実行するために用いた計算式および計算条件の詳細は後述する。
以下、図14を参照しながら、本発明による窒化ガリウム系化合物半導体の製造方法により、半導体発光素子を製造する実施形態を説明する。
410nm → In組成: 8-12%
430nm → In組成:13-17%
450nm → In組成:18-22%
475nm → In組成:24-28%
500nm → In組成:30%以上
図12に示すシミュレーションに用いた計算式および計算条件を説明する。
ΔNsol:各原子が時間Δtの間に固化する正味の固化量、
ω0:各原子のデバイ振動数、
kB:ボルツマン定数、
T:環境温度、
εsol:各原子が固化するのに必要なエネルギー、
εdif:各原子が結晶表面で最隣接する別の位置に拡散するのに必要なエネルギー
102 n-GaN層
103 GaNバリア層
104 InxGa1-xN(0<x<1)井戸層
105 GaN/InGaN多重量子井戸発光層
106 p-GaN層
107 n電極
108 p電極
201 N原子
301 基板
302 石英トレイ
303 カーボンサセプタ
304 石英フローチャネル
305 水冷ジャケット
306 熱電対
Claims (8)
- 発光ピーク波長が500nm以上であるm面InGaN層を有機金属気相成長法によって成長させる窒化ガリウム系化合物半導体の製造方法であって、
反応室内の基板を加熱する工程(A)と、
In原料ガス、Ga原料ガス、およびN原料ガスを含むガスを前記反応室内に供給し、700℃から775℃までの成長温度でInxGa1-xN結晶からなるm面InGaN層を前記基板上に成長させる工程(B)と、
を含み、
前記工程(B)において、前記m面InGaN層の成長速度を4.5nm/分から10nm/分までの範囲内に設定する窒化ガリウム系化合物半導体の製造方法。 - 発光ピーク波長が450nmから500nmまでの範囲内にあるm面InGaN層を有機金属気相成長法によって成長させる窒化ガリウム系化合物半導体の製造方法であって、
反応室内の基板を加熱する工程(A)と、
In原料ガス、Ga原料ガス、およびN原料ガスを含むガスを前記反応室内に供給し、775℃から785℃までの成長温度でInxGa1-xN結晶からなるm面InGaN層を前記基板上に成長させる工程(B)と、
を含み、
前記工程(B)において、前記m面InGaN層の成長速度を3nm/分から10nm/分までの範囲内に設定する窒化ガリウム系化合物半導体の製造方法。 - 発光ピーク波長が425nmから475nmまでの範囲内にあるm面InGaN層を有機金属気相成長法によって成長させる窒化ガリウム系化合物半導体の製造方法であって、
反応室内の基板を加熱する工程(A)と、
In原料ガス、Ga原料ガス、およびN原料ガスを含むガスを前記反応室内に供給し、770℃から790℃までの成長温度でInxGa1-xN結晶からなるm面InGaN層を前記基板上に成長させる工程(B)と、
を含み、
前記工程(B)において、前記m面InGaN層の成長速度を8nm/分以上に設定する窒化ガリウム系化合物半導体の製造方法。 - 発光ピーク波長が425nmから475nmまでの範囲内にあるm面InGaN層を有機金属気相成長法によって成長させる窒化ガリウム系化合物半導体の製造方法であって、
反応室内の基板を加熱する工程(A)と、
In原料ガス、Ga原料ガス、およびN原料ガスを含むガスを前記反応室内に供給し、770℃から790℃までの成長温度でInxGa1-xN結晶からなるm面InGaN層を成長させる工程(B)と、
を含み、
前記工程(B)において、前記m面InGaN層の成長速度を4nm/分から5nm/分までの範囲内に設定する窒化ガリウム系化合物半導体の製造方法。 - 基板を用意する工程と、
発光層を有する半導体積層構造を前記基板上に形成する工程と、
を含み、
前記半導体積層構造を形成する工程は、
請求項1から4のいずれかに記載の窒化ガリウム系化合物半導体の製造方法によってm面InGaN層を形成する工程を含む、半導体発光素子の製造方法。 - 前記発光層は多重量子井戸構造を有しており、
前記m面InGaN層は前記多重量子井戸構造に含まれる井戸層である、請求項5に記載の半導体発光素子の製造方法。 - 前記基板を除去する工程を含む、請求項5に記載の半導体発光素子の製造方法。
- 請求項1から4のいずれかに記載の窒化ガリウム系化合物半導体の製造方法によって形成されたm面InGaN層を含む発光層と、
前記発光層に電荷を供給するための電極と、
を備える半導体発光素子。
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JP2012038824A (ja) * | 2010-08-04 | 2012-02-23 | Toshiba Corp | 半導体発光素子の製造方法 |
WO2012140844A1 (ja) * | 2011-04-12 | 2012-10-18 | パナソニック株式会社 | 窒化ガリウム系化合物半導体発光素子およびその製造方法 |
JP2013544739A (ja) * | 2010-11-08 | 2013-12-19 | コリア フォトニクス テクノロジー インスティテュート | 化学リフトオフ方法を用いたiii族窒化物基板の製造方法 |
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