JP2012059874A - MANUFACTURING METHOD OF ZnO-BASED SEMICONDUCTOR LAYER AND MANUFACTURING METHOD OF ZnO-BASED SEMICONDUCTOR LIGHT-EMITTING ELEMENT - Google Patents

Abstract

A novel method for producing a ZnO-based semiconductor single crystal is provided.
A method of manufacturing a ZnO-based semiconductor layer includes: (a) Mg _x Zn _1-x O (0 ≦ x ≦ 0.6) on a base having a single crystal surface, (Mg _y Zn _1-y ) ₃ A step of growing a N ₂ (0 ≦ y ≦ 0.6) single crystal film, and (b) oxidizing the (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film. Then, an N-doped Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) single crystal film is formed.
[Selection] Figure 11

Description

  The present invention relates to a method for manufacturing a ZnO-based semiconductor layer and a method for manufacturing a ZnO-based semiconductor light emitting device.

A method for obtaining ZnO by oxidizing Zn ₃ N ₂ has been proposed. Considering application to semiconductor elements such as light emitting diodes, it is desirable to obtain single crystal ZnO. However, it is difficult to obtain a ZnO single crystal by such a method.

Appl. Phys. Lett. 88 (2006) 172103. J. Crystal Growth 259 (2003) 279. Solid State Communication 135 (2005) 11.

  An object of the present invention is to provide a novel method for manufacturing a ZnO-based semiconductor single crystal and a method for manufacturing a ZnO-based semiconductor light-emitting element using such a method for manufacturing a ZnO-based semiconductor single crystal.

According to one aspect of the present invention, (a) Mg _x Zn _1-x O (0 ≦ x ≦ 0.6) (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) a step of growing a single crystal film, and (b) oxidizing the (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film to form N-doped And a step of forming a Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) single crystal film.

A (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film can be grown on the surface of the Mg _x Zn _1-x O (0 ≦ x ≦ 0.6) single crystal. . By oxidizing a (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film, an N-doped Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) single crystal film is obtained. Can be obtained.

FIG. 1 is a schematic sectional view of an MBE apparatus. FIG. 2 is a graph showing the Zn flux and growth temperature dependence of the growth rate of the Zn ₃ N ₂ film. FIG. 3A is a schematic cross-sectional view showing a sample structure of the second experiment, FIGS. 3B1 to 3B4 are RHEED images of the sample of the second experiment, and FIG. 3C is an XRD 2θ / It is a graph which shows a omega scan measurement result. FIG. 4A is a schematic cross-sectional view showing a sample structure of the third experiment, FIGS. 4B1 to 4B4 are RHEED images of the sample of the third experiment, and FIG. 4C is an XRD 2θ / It is a graph which shows a omega scan measurement result. 5A and 5B are graphs showing the XRD Φ scan measurement results for the samples of the second experiment and the third experiment, respectively. 6A is a schematic cross-sectional view showing a sample structure of the fourth experiment, FIGS. 6B1 to 6B4 are RHEED images of the sample of the fourth experiment, and FIG. 6C is an XRD 2θ / It is a graph which shows a omega scan measurement result. FIG. 7A is a schematic cross-sectional view showing the sample structure of the fifth experiment, FIGS. 7B1 to 7B4 are RHEED images of the sample of the fifth experiment, and FIG. 7C is the XRD 2θ / It is a graph which shows a omega scan measurement result. FIG. 8 is a schematic cross-sectional view of an oxidation electric furnace. FIG. 9 is a table summarizing various physical properties of Zn ₃ N ₂ , Mg ₃ N ₂ , ZnO, and MgO. FIG. 10A shows the XRD pattern of the sample of the sixth experiment, and FIG. 10B is a graph showing the change of the XRD peak intensity of the sample of the sixth experiment with respect to the oxidation time. FIG. 11A shows the XRD pattern of the sample of the seventh experiment, and FIG. 11B is a graph showing the change of the XRD peak intensity of the sample of the seventh experiment with respect to the oxidation time. FIG. 12 is a table summarizing the electrical characteristics and N concentration of the samples of the sixth to eighth experiments. FIG. 13 is a timing chart showing the temperature in the oxidation process of the eighth experiment and the supply state of H ₂ O gas and O ₂ gas. FIG. 14A is a schematic cross-sectional view showing the structure of a ZnO-based semiconductor light emitting device of a first application example, and FIG. 14B is a schematic cross-sectional view showing an active layer having a quantum well structure. FIG. 15 is a schematic cross-sectional view showing the structure of a ZnO-based semiconductor light emitting device of the second application example.

  The inventors of the present application propose a novel method for producing a ZnO-based semiconductor single crystal doped with N, as will be described below. Here, the ZnO-based semiconductor includes at least Zn and O. Hereinafter, ZnO doped with N is referred to as ZnO: N. For example, when considering application to a ZnO-based semiconductor element such as a light-emitting diode, the ZnO: N film is preferably a single crystal and can be formed on a ZnO-based semiconductor substrate.

The inventors of the present application tried to obtain a ZnO: N single crystal film by oxidizing the Zn ₃ N ₂ single crystal film. Therefore, an experiment for growing a Zn ₃ N ₂ single crystal film was conducted. A molecular beam epitaxy (MBE) apparatus was used for forming the Zn ₃ N ₂ film.

FIG. 1 is a schematic cross-sectional view of an MBE apparatus used for forming a Zn ₃ N ₂ single crystal film. Here, as the MBE apparatus, an apparatus capable of forming a ZnO film or an MgO film formed in the later-described fourth and fifth experiments, each layer formed at the time of manufacturing the ZnO-based semiconductor light emitting element of the application example, and the like will be described.

  The vacuum chamber 1 includes a Zn source gun 2, an Mg source gun 3, a Ga source gun 4, an O source gun 5, and an N source gun 6 (if necessary). Each of the Zn source gun 2, the Mg source gun 3, and the Ga source gun 4 includes a Zn solid source (eg, purity 7N), an Mg solid source (eg, purity 6N), and a Knudsen cell containing a Ga solid source, and a Zn beam. , Mg beam and Ga beam are emitted. The Knudsen cell includes a pyrolytic boron nitride (PBN) crucible and a heater that heats the crucible.

  Note that the n-type conductivity of the ZnO-based semiconductor can be obtained without adding an n-type impurity, but Ga can also be added to increase the n-type carrier concentration.

Each of the O source gun 5 and the N source gun 6 includes an electrodeless discharge tube using a radio frequency (RF) of 13.56 MHz, for example, and emits an O radical beam and an N radical beam. As the discharge tube material, PBN or high-purity quartz is used. O ₂ through the mass flow controller 5b from the cylinder 5a, O source and comprising _{O 2} gas (e.g. purity 6N) is supplied to the O source gun 5. Through the N ₂ gas cylinder 6a mass flow controller 6b, the N source _{N 2} gas (e.g. purity 6N) is supplied to the N source gun 6.

  A substrate holder 7 including a heater is disposed in the vacuum chamber 1, and the holder 7 holds the substrate 8. A crystal layer having a desired composition can be grown on the substrate 8 by supplying a desired beam. In the vacuum chamber 1, a film thickness meter 9 using a quartz resonator is provided. From the deposition rate measured by the film thickness meter 9, a flux such as a Zn beam is obtained.

  The MBE apparatus also includes a reflection high-energy electron diffraction (RHEED) gun 10, a screen 11 that displays an RHEED image, and an RHEED image display device 12 that includes a solid-state imaging device and a monitor. From the RHEED image, the crystallinity of the grown crystal layer can be determined.

Next, a first experiment in which the conditions under which a Zn ₃ N ₂ single crystal film can be formed will be described. In the first experiment, a Zn ₃ N ₂ film was grown on an a-plane sapphire substrate. The a-plane sapphire substrate used was a 10 mm square.

The supply conditions of the N radical beam were constant, with the RF power being 300 W and the N ₂ flow rate being ₂ sccm. The supply condition of the Zn beam varies in the range of Zn flux from 0.05 nm / s to 0.65 nm / s (3.3 × 10 ¹⁴ atoms / cm ^{2 s to} 4.3 × 10 ¹⁵ atoms / cm ² s). I let you. And the growth temperature was changed in the range of 200 degreeC-250 degreeC.

FIG. 2 is a graph showing the Zn flux and growth temperature dependence of the growth rate of the Zn ₃ N ₂ film. The horizontal axis represents Zn flux (F _Zn ) expressed in deposition rate in units of Å / s, and the vertical axis represents the growth rate of Zn ₃ N ₂ film expressed in nm / h units. The results at the growth temperature (Tg) of 200 ° C., 225 ° C., and 250 ° C. are shown as circle, square, and triangle plots, respectively.

It can be seen that the growth rate of the Zn ₃ N ₂ film greatly depends on the growth temperature and decreases as the growth temperature increases. In the figure 2 shows the results of fitting the Zn flux dependence of the growth rate approximation formula _{G Zn3N2 = [(k Zn J} Zn) -1 + (k N J N) -1] -1 by curve . Here _k Zn, _{k N} is the number of irradiation atoms per sticking _coefficient, J Zn, _{J N} unit area per unit time in the flux of each Zn and N, respectively Zn and N. When k _N J _N is 2′10 ¹⁴ atoms / cm ² s and the growth temperatures Tg are 200 ° C., 225 ° C., and 250 ° C., the Zn adhesion coefficient k _Zn is 0.2, 0.03,. 002 was estimated. The Zn ₃ N ₂ film did not grow at all when the growth temperature exceeded 300 ° C.

The crystallinity of the Zn ₃ N ₂ film was evaluated by RHEED. When the growth temperature is in the range of 200 ° C. to 250 ° C. and the growth rate is 100 nm / h or less, the RHEED image shows a (4 × 4) reconstruction pattern with streaks, and the Zn ₃ N ₂ single crystal film grows epitaxially. I understood it. When the growth rate was 100 nm / h or more, it was found that the RHEED image showed a ring pattern and a polycrystalline film grew.

Furthermore, an experiment for growing a Zn ₃ N ₂ film on a c-plane sapphire substrate and an experiment for growing a Zn ₃ N ₂ film on a ZnO substrate were also performed.

It was confirmed that when a Zn ₃ N ₂ film was grown on a c-plane sapphire substrate under the growth conditions for growing the above-described single crystal film, the RHEED image became a spot-ring pattern and only a polycrystalline film was grown.

When a Zn ₃ N ₂ film is grown on a ZnO substrate under the above-described growth conditions for growing a single crystal film, the RHEED image is streak (4 ×) as in the case of growing on an a-plane sapphire substrate. The reconstruction pattern of 4) was shown, and it was found that the Zn ₃ N ₂ single crystal film was epitaxially grown.

Next, a second experiment in which the crystal orientation of the Zn ₃ N ₂ single crystal film grown on the a-plane sapphire substrate is examined will be described.

FIG. 3A is a schematic cross-sectional view showing a sample structure of a second experiment. On the a-plane sapphire substrate 21, the growth temperature is set to 225 ° C., the Zn flux is set to 0.12 nm / s (7.9 × 10 ¹⁴ atoms / cm ² s), and the N radical beam irradiation condition is set to N with RF power of 300 W. _A Zn ₃ N ₂ film 22 was grown at a flow rate of ₂ sccm.

3B1 to 3B4 are RHEED images of the sample of the second experiment. 3B1 is a RHEED image in the [0001] direction of the sapphire substrate, FIG. 3B2 is a RHEED image in the [1-100] direction of the sapphire substrate, and FIG. 3B3 is a [1-10] of the Zn ₃ N ₂ film. ] FIG. 3B4 is a RHEED image in the [11-2] direction of the Zn ₃ N ₂ film.

  FIG. 3C is a graph showing the X-ray diffraction (XRD) 2θ / ω scan measurement result for the sample of the second experiment.

  FIG. 5A is a graph showing the XRD Φ scan measurement results for the sample of the second experiment.

In XRD 2θ / ω scan measurement, diffraction peaks from the (11-20) plane and (22-40) plane of the sapphire substrate, and diffraction peaks from the (222) plane and (444) plane of the Zn ₃ N ₂ film Only Zn was observed, and it was found that the Zn ₃ N ₂ (111) plane was epitaxially grown on the sapphire (11-20) plane.

Also, from the RHEED and XRD Φ scan measurements, the in-plane directions are Zn ₃ N ₂ [11-2] + 8 ° // sapphire [1-100] and Zn ₃ N ₂ [1-10] + 8 ° // sapphire. The result of [0001] was obtained, and it was found that the Zn ₃ N ₂ film was oriented by rotating about 8 ° from the m-axis of sapphire.

Next, a third experiment in which the crystal orientation of the Zn ₃ N ₂ single crystal film grown on the Zn-face ZnO substrate is examined will be described.

FIG. 4A is a schematic cross-sectional view showing a sample structure of a third experiment. On the Zn surface ZnO substrate 31, as in the third experiment, the growth temperature is 225 ° C., the Zn flux is 0.12 nm / s (7.9 × 10 ¹⁴ atoms / cm ² s), and N radical beam irradiation conditions are set. The Zn ₃ N ₂ film 32 was grown at an RF power of 300 W and an N ₂ flow rate of ₂ sccm.

4B1 to 4B4 are RHEED images of the sample of the third experiment. 4B1 is a RHEED image of the [11-20] direction of the ZnO substrate, FIG. 4B2 is a RHEED image of the [1-100] direction of the ZnO substrate, and FIG. 4B3 is a [1] of the Zn ₃ N ₂ film. FIG. 4B4 is a RHEED image in the [11-2] direction of the Zn ₃ N ₂ film.

  FIG. 4C is a graph showing the XRD 2θ / ω scan measurement results for the sample of the third experiment.

  FIG. 5B is a graph showing the XRD Φ scan measurement result for the sample of the third experiment.

In XRD 2θ / ω scan measurement, only diffraction peaks from the (0002) and (0004) planes of the ZnO substrate and diffraction peaks from the (222) and (444) planes of the Zn ₃ N ₂ film were observed. It was found that the Zn ₃ N ₂ (111) plane was epitaxially grown on the ZnO (0001) plane.

Further, from the RHEED and XRD Φ scan measurements, the in-plane directions are Zn ₃ N ₂ [11-2] // ZnO [1-100] and Zn ₃ N ₂ [1-10] // ZnO [11-20]. It turns out that The streak pattern of Zn ₃ N ₂ appeared approximately 6% inside the streak pattern of ZnO corresponding to the lattice mismatch.

  In the third experiment, a Zn-face ZnO substrate was used, but similar results were obtained with an O-face ZnO substrate.

Next, a fourth experiment in which a ZnO epitaxial growth film is formed on an a-plane sapphire substrate and a Zn ₃ N ₂ film is grown on the ZnO epitaxial growth film will be described.

FIG. 6A is a schematic cross-sectional view showing a sample structure of a fourth experiment. On the a-plane sapphire substrate 41, a growth temperature is set to 300 ° C., a Zn flux is set to 0.11 nm / s, an O radical beam irradiation condition is set to an RF power of 300 W, an O ₂ flow rate of ₂ sccm, and a low-temperature ZnO buffer having a thickness of about 30 nm. Layer 42 was grown. Then, annealing was performed at 900 ° C. for 30 minutes in order to improve the crystallinity and surface flatness of the low-temperature ZnO buffer layer 42.

Then, a ZnO film 43 having a thickness of about 1 μm was grown at a growth temperature of 700 ° C., a Zn flux of 0.35 nm / s, an O radical beam irradiation condition of RF power of 300 W and an O ₂ flow rate of ₂ sccm. The ZnO film 43 is grown on the O polar plane (−c plane).

Further, a Zn ₃ N ₂ film 44 having a thickness of about 100 nm is grown at a growth temperature of 225 ° C., a Zn flux of 0.11 nm / s, an N radical beam irradiation condition of an RF power of 300 W and an N ₂ flow rate of ₂ sccm. It was.

6B1 to 6B4 are RHEED images of the sample of the fourth experiment. 6B1 is a [11-20] direction RHEED image of the ZnO underlayer, FIG. 6B2 is a [1-100] direction RHEED image of the ZnO underlayer, and FIG. 6B3 is a Zn ₃ N ₂ layer. FIG. 6B4 is an RHEED image in the [112] direction of the Zn ₃ N ₂ film. In these RHEED images, screen stains appear as diagonal lines (this is the same in FIGS. 7B1 to 7B4 of the fifth experiment described later).

  FIG. 6C is a graph showing the XRD 2θ / ω scan measurement results for the sample of the fourth experiment.

Only the diffraction peaks related to the a-plane of the sapphire substrate, the c-plane of ZnO, and the Zn ₃ N ₂ (111) plane are observed, and the epitaxial growth direction is Zn ₃ N ₂ (111) // ZnO (000-1) // It was found to be sapphire (11-20). The in-plane directions are Zn ₃ N ₂ [11-2] // ZnO [1-100] // sapphire [1-100] and Zn ₃ N ₂ [1-10] // ZnO [11-20]. ] // Sapphire [0001].

Next, a fifth experiment in which a ZnO epitaxial growth film is formed on a c-plane sapphire substrate and a Zn ₃ N ₂ film is grown on the ZnO epitaxial growth film will be described.

FIG. 7A is a schematic cross-sectional view showing a sample structure of a fifth experiment. On the c-plane sapphire substrate 51, the growth temperature is set to 650 ° C., the Mg flux is set to 0.05 nm / s, the O radical beam irradiation conditions are set to an RF power of 300 W, an O ₂ flow rate of ₂ sccm, and a MgO film 52 having a thickness of about 10 nm. Grew. The MgO film 52 functions as a polarity control layer on which ZnO having a Zn polar surface is grown.

On the MgO film 52, the growth temperature is 300 ° C., the Zn flux is 0.11 nm / s, the O radical beam irradiation conditions are an RF power of 300 W, an O ₂ flow rate of ₂ sccm, and a low-temperature ZnO buffer layer 53 having a thickness of about 30 nm. Grew. Then, annealing was performed at 900 ° C. for 30 minutes in order to improve crystallinity and surface flatness of the low temperature ZnO buffer layer 53.

Then, the growth temperature was set to 900 ° C., the Zn flux was set to 0.05 nm / s, the O radical beam irradiation conditions were set to an RF power of 300 W, an O ₂ flow rate of ₂ sccm, and a ZnO film 54 having a thickness of about 1.5 μm was grown. . The ZnO film 54 is grown on the Zn polar face (+ c face).

Further, a Zn ₃ N ₂ film 55 having a thickness of about 100 nm is grown at a growth temperature of 225 ° C., a Zn flux of 0.11 nm / s, an N radical beam irradiation condition of an RF power of 300 W and an N ₂ flow rate of ₂ sccm. It was.

7B1 to 7B4 are RHEED images of the sample of the fifth experiment. Figure 7B1 is a RHEED image of the [11-20] direction of the ZnO base film, Fig. 7B2 is a RHEED image of the [1-100] direction of the ZnO base film, Fig. 7B3 is a _Zn 3 _{N 2} film [110] direction RHEED image, FIG. 7B4 is a [112] direction RHEED image of the Zn ₃ N ₂ film.

  FIG. 7C is a graph showing the XRD 2θ / ω scan measurement results for the sample of the fifth experiment.

Only diffraction peaks relating to the c-plane of the sapphire substrate, the MgO (111) plane, the c-plane of ZnO, and the Zn ₃ N ₂ (111) plane are observed, and the epitaxial growth direction is Zn ₃ N ₂ (111) // ZnO ( 0001) // MgO (111) // Sapphire (0001). Also, in-plane direction, Zn ₃ N ₂ [11-2] // ZnO [1-100] // MgO [11-2] // sapphire [11-20], and Zn ₃ N ₂ [1-10] // ZnO [11-20] // MgO [1-10] // Sapphire [1-100].

As described in the fourth and fifth experiments, even when a substrate other than ZnO is used, the Zn ₃ N ₂ (111) plane is epitaxially grown on the ZnO single crystal underlayer by epitaxially growing ZnO on the substrate. I found out that Similar results can be obtained by using a MgZnO single crystal film obtained by adding Mg to ZnO instead of the ZnO single crystal film.

The inventors further conducted an experiment to obtain a ZnO: N film by oxidizing a Zn ₃ N ₂ single crystal film. First, the oxidation apparatus will be described.

FIG. 8 is a schematic cross-sectional view of an oxidizing electric furnace used for oxidizing a Zn ₃ N ₂ film. A sample 63 is placed on a susceptor 62 disposed in the chamber 61, and a heater 64 heats the sample 63.

From O ₂ source 65a through a mass flow controller 65b, _{O 2} gas is supplied into the chamber 61. Through a mass flow controller 66b from H ₂ O source 66a, _{H 2} O gas is supplied into the chamber 61. For example, H ₂ O gas can be supplied as follows. The water bottle is heated to, for example, 110 ° C. to generate water vapor, and H ₂ O gas is supplied through a pipe heated to, for example, about 200 ° C. and a high-temperature mass flow controller.

Next, a sixth experiment in which a Zn ₃ N ₂ single crystal film is oxidized in an O ₂ gas flow to obtain a ZnO: N film will be described. The Zn ₃ N ₂ single crystal film was grown on the a-plane sapphire substrate under the same film formation conditions as in the second experiment.

The as-grown Zn ₃ N ₂ single crystal film exhibits a dark gray color that is opaque and has a metallic luster. The Zn ₃ N ₂ film becomes a translucent brown color when oxidized. When the oxidation further progresses to a complete ZnO: N film, a colorless and transparent film can be obtained. This is considered to correspond to the change of the band gap as discussed below.

  As will be described later, the ZnO: N film of the sample of the sixth experiment appears whitish (white turbid) due to light scattering by the surface uneven structure. The ZnO: N films of the samples of the seventh and eighth experiments have good surface flatness and are colorless and transparent without white turbidity.

FIG. 9 is a table summarizing various physical properties of Zn ₃ N ₂ , Mg ₃ N ₂ , ZnO, and MgO. Zn ₃ N ₂ has a band gap close to 1.06 eV and a band gap of Si (1.1 eV), and exhibits the same color as Si. When the oxidation of the Zn ₃ N ₂ film partially proceeds, the portion changed to ZnO and the portion of Zn ₃ N ₂ are mixed, and the band gap of O-doped Zn ₃ N ₂ is slightly expanded. Is inferred. As a result, the film becomes brown. When the oxidation further proceeds and the entire film changes to ZnO, the band gap of ZnO is 3.37 eV and is transparent in the visible light region, so that a colorless and transparent film can be obtained.

  10A and 10B are graphs showing the XRD 2θ / ω scan measurement results in the sixth experiment.

In the experiment whose result is shown in FIG. 10A, a Zn ₃ N ₂ film having a thickness of 200 nm was formed and oxidized. The oxidation conditions were an O ₂ flow rate of 200 sccm, a pressure of 50 kPa, an oxidation time of 30 minutes, and an oxidation temperature in the range of 550 ° C. to 700 ° C.

FIG. 10A shows an XRD pattern of a sample that is as-grown and not oxidized, and an XRD pattern of a sample in which the oxidation temperature is changed by 50 ° C. The higher the oxidation temperature, the more the oxidation proceeds, and the diffraction from the Zn ₃ N ₂ (222) plane disappears at 650 ° C. or higher, and all changes to the diffraction from the ZnO (0002) plane.

In the experiment whose result is shown in FIG. 10B, a Zn ₃ N ₂ film having a thickness of 200 nm was formed and oxidized. The oxidation conditions were an O ₂ flow rate of 200 sccm, a pressure of 50 kPa, an oxidation temperature of 550 ° C., and an oxidation time of 0 to 180 minutes.

FIG. 10B is a graph showing changes in XRD peak intensity with respect to oxidation time. The peak intensity of the Zn ₃ N ₂ (222) plane is normalized to the peak intensity of the as-grown Zn ₃ N ₂ single crystal film as 1, and the peak intensity of the ZnO (0002) plane is completely changed to ZnO. The peak intensity of the changed ZnO: N single crystal film is normalized to 1 and shown. The peak intensity of Zn ₃ N ₂ is shown as a rhombus plot, and the peak intensity of ZnO is shown as a circle plot.

As the oxidation time becomes longer, the peak intensity of the Zn ₃ N ₂ (222) plane decreases, and accordingly the peak intensity of the ZnO (0002) plane increases, that is, the oxidation progresses, so that Zn ₃ N ₂ It can be seen that the (111) film changes to a ZnO (0001) film.

In the case of 180 minutes oxidation treatment, the peak of the Zn ₃ N ₂ (222) plane disappeared completely, and all became the peak of the ZnO (0002) plane. Except for the substrate, no peaks from other diffraction planes were observed, and it was found that the change from Zn ₃ N ₂ to ZnO maintained a single crystal state. The ZnO: N film obtained in this way was a film with a surface turbidity and poor surface flatness, and the film was easily peeled off by an adhesive tape and had poor adhesion to the substrate.

Further, a Zn ₃ N ₂ film having a thickness of 50 nm was formed, and oxidation was performed with an O ₂ flow rate of 200 sccm, a pressure of 50 kPa, an oxidation temperature of 600 ° C., and an oxidation time of 30 minutes, thereby producing a ZnO: N film (this The sample was called Sample A), and the electrical properties and N concentration of Sample A were measured. The electrical characteristics were measured by hole measurement at room temperature, and the N concentration was measured by secondary ion mass spectrometry (SIMS).

Next, a seventh experiment in which a ZnO: N film is obtained by oxidizing a Zn ₃ N ₂ single crystal film in a H ₂ O gas flow will be described. The Zn ₃ N ₂ single crystal film was grown on the a-plane sapphire substrate under the same film formation conditions as in the second experiment.

  11A and 11B are graphs showing the XRD 2θ / ω scan measurement results in the seventh experiment.

In the experiment whose result is shown in FIG. 11A, a Zn ₃ N ₂ film having a thickness of 200 nm was formed and oxidized. The oxidation conditions were as follows: the H ₂ O flow rate was 200 sccm, the pressure was 50 kPa, the oxidation time was constant at 2 minutes, and the oxidation temperature was changed in the range of 400 ° C. to 700 ° C.

FIG. 11A shows an XRD pattern of a sample with as-grown and no oxidation, and an XRD pattern of a sample in which the oxidation temperature is changed by 100 ° C. Similar to the sixth experiment using O ₂ gas oxidation, the higher the oxidation temperature, the more the oxidation proceeds. Diffraction from the Zn ₃ N ₂ (222) plane disappears between 600 ° C. and 700 ° C., and all changes to diffraction from the ZnO (0002) plane.

In the experiment whose result is shown in FIG. 11B, a Zn ₃ N ₂ film having a thickness of 200 nm was formed and oxidized. The oxidation conditions were such that the H ₂ O flow rate was 200 sccm, the pressure was 50 kPa, the oxidation temperature was kept constant at 600 ° C., and the oxidation time was varied in the range of 0 to 20 minutes.

FIG. 11B is a graph showing the change of the XRD peak intensity with respect to the oxidation time. The peak intensity of the Zn ₃ N ₂ (222) plane and the peak intensity of the ZnO (0002) plane are normalized and shown as in FIG. 10B of the sixth experiment.

As in the sixth experiment using O ₂ gas oxidation, it was found that as the oxidation progressed, the Zn ₃ N ₂ (111) single crystal film was changed to a ZnO (0001) single crystal film. In the oxidation treatment for 20 minutes, the peak of the Zn ₃ N ₂ (222) plane disappeared completely, and all became the peak of the ZnO (0002) plane.

  The ZnO: N film thus obtained had a mirror surface with high surface flatness and good adhesion to the substrate.

Further, a Zn ₃ N ₂ film having a thickness of 50 nm was formed, and oxidation was performed with an H ₂ O flow rate of 200 sccm, a pressure of 50 kPa, an oxidation temperature of 600 ° C., and an oxidation time of 10 minutes, thereby producing a ZnO: N film ( This sample is called Sample B), and the electrical characteristics and N concentration of Sample B were measured.

It takes 180 minutes in the example of FIG. 10B of the sixth experiment and 20 minutes in the example of FIG. 11B of the seventh experiment until the Zn ₃ N ₂ peaks disappear and become all ZnO. Thus, it was found that oxidation using H ₂ O gas has a higher oxidation rate than oxidation using O ₂ gas. This tendency was the same even when oxidation using H ₂ O gas was performed at 500 ° C.

In the case of oxidation using H ₂ O gas, the peak intensity of Zn ₃ N ₂ is reduced by about 80% in the initial 2 minutes in the example of FIG. 11B. This seems to suggest a mechanism that the surface of the Zn ₃ N ₂ film is rapidly oxidized in the oxidation using H ₂ O gas.

FIG. 12 is a table summarizing electrical characteristics and N concentrations of Sample A of the sixth experiment and Sample B of the seventh experiment. Electrical characteristics are also measured for a Zn ₃ N ₂ epi film which is an oxidation start material, and the electrical characteristics of Zn ₃ N ₂ are also shown.

The Zn ₃ N ₂ film exhibited low-resistance n-type conductivity, and had a carrier concentration of 2.9 × 10 ¹⁹ cm ⁻³ , a mobility of 214 cm ² / Vs, and a specific resistance of 0.001 Ωcm.

The ZnO: N film of Sample A obtained by O ₂ gas oxidation showed a high resistance with a specific resistance of 1000 Ωcm or more, and the N concentration was 1.1 × 10 ²⁰ cm ⁻³ . On the other hand, the ZnO: N film of Sample B obtained by H ₂ O gas oxidation exhibits n-type conductivity, the carrier concentration is 6.9 × 10 ¹⁹ cm ⁻³ , the mobility is 1.1 cm ² / Vs, The specific resistance was 0.085 Ωcm, and the N concentration was 1.0 × 10 ²¹ cm ⁻³ . Thus, it has been clarified that the electrical characteristics of the obtained ZnO: N film are extremely different depending on the gas type of the oxidizing gas.

As described above, H ₂ O oxidation is superior to O ₂ oxidation in terms of film adhesion and surface flatness. This seems to be explained by the relationship between the sublimation rate of Zn ₃ N ₂ and the oxidation rate as follows.

Although the boiling point of Zn ₃ N ₂ is not clear, as shown in FIG. 9, since the boiling point of Mg ₃ N ₂ (700 ° C.) is lower than the melting point (800 ° C.), Zn ₃ N ₂ is also sublimable. It is assumed that the boiling point is lower than that of Mg ₃ N ₂ . For example, when the temperature is raised to 600 ° C. after growth in the MBE chamber, the Zn ₃ N ₂ film disappears in a few seconds.

Oxidation with O ₂ gas is weak in oxidizing power, and it is considered that adhesion and surface flatness of the film are deteriorated due to simultaneous sublimation and oxidation of Zn ₃ N ₂ occurring in the surface. On the other hand, the oxidation with H ₂ O gas has a strong oxidizing power, so the surface immediately changes to a ZnO film on the entire surface of the Zn ₃ N ₂ film, and then the oxidation inside the film proceeds. It seems that the surface flatness is improved.

Note that the mechanism by which the ZnO: N film obtained by H ₂ O gas oxidation exhibits n-type conductivity is not well understood at present.

Next, an eighth experiment in which a ZnO: N film is obtained by sequentially oxidizing a Zn ₃ N ₂ single crystal film with H ₂ O gas and O ₂ gas will be described. First, a Zn ₃ N ₂ single crystal film having a thickness of 50 nm was grown on an a-plane sapphire substrate under the same film formation conditions as in the second experiment.

FIG. 13 is a timing chart showing the temperature in the oxidation process of the eighth experiment and the supply state of H ₂ O gas and O ₂ gas.

First, heating was started in a vacuum, and when the temperature reached 300 ° C., introduction of H ₂ O gas was started. After the temperature was raised to 600 ° C., oxidation was performed at an oxidation temperature of 600 ° C. for 2 minutes. The conditions for introducing the H ₂ O gas were a flow rate of 200 sccm and a pressure of 50 kPa.

Then, the introduced gas was switched from H ₂ O to O ₂ , and the oxidation temperature was continuously set to 600 ° C. to perform oxidation for 10 minutes. The conditions for introducing the O ₂ gas were a flow rate of 200 sccm and a pressure of 50 kPa.

Thereafter, the introduced gas was switched from O ₂ to N ₂ (flow rate 500 sccm), and the sample was cooled. In this way, a ZnO: N film was produced (this sample is referred to as sample C). The film of sample C is colorless and transparent, and it can be judged from the film color that it has been completely oxidized to ZnO. The electrical properties and N concentration of sample C were measured.

FIG. 12 also shows the electrical characteristics and N concentration of Sample C of the eighth experiment. The ZnO: N film of Sample C obtained by sequential oxidation with H ₂ O gas and O ₂ gas exhibits p-type conductivity, carrier concentration is 4.5 × 10 ¹⁶ cm ⁻³ , and mobility is 8. The specific resistance was 4 cm ² / Vs, the specific resistance was 16.8 Ωcm, and the N concentration was 4.2 × 10 ²⁰ cm ⁻³ . The ZnO: N film of Sample C had a mirror surface and good adhesion to the substrate.

In the 8th experiment, it is considered that oxidation occurs by the following mechanism. First, Zn ₃ N ₂ sublimation is prevented by rapidly oxidizing the surface of the Zn ₃ N ₂ film with a highly oxidizing H ₂ O gas and providing a ZnO film as a surface cap layer. Note that the oxidation with H ₂ O gas is considered to have started during the temperature rise.

Thereafter, the oxidation inside the film is allowed to proceed relatively slowly with O ₂ gas having weak oxidizing power. It is considered that a ZnO: N film having excellent surface flatness and film adhesion can be produced by such oxidation. And it seems that p-type conductivity could be obtained by performing such two-step oxidation.

In such two-step oxidation, it is considered that the strong oxidizing gas is not limited to H ₂ O, and the weak oxidizing gas is not limited to O ₂ . As an oxidizing gas that is relatively strong to the oxidizing gas used for the second-stage oxidation used in the first-stage oxidation, for example, a polar oxidant such as H ₂ O, ozone, methyl alcohol, and ethyl alcohol, or O Active species such as radicals, etc. could be used alone or in combination.

Further, as an oxidizing gas that is relatively weak with respect to the oxidizing gas used for the first stage oxidation used in the second stage oxidation, for example, O ₂ , N ₂ O, CO ₂ , NO, NO _2, etc. Apolar oxidants could be used alone or in combination.

It is considered that the oxidation with the strong oxidizing gas in the first stage is preferably performed until the surface ZnO film is formed to a thickness that functions as a cap layer that suppresses sublimation of Zn ₃ N ₂ inside. . The preferable thickness of the cap layer is considered to be somewhat dependent on the thickness of the original Zn ₃ N ₂ film and the processing temperature, but is estimated to be about 5 nm to 30 nm, for example.

If the cap layer is too thin, sublimation of Zn ₃ N ₂ cannot be prevented. For example, in the range of about 1 nm to 2 nm, sublimation of Zn ₃ N ₂ at 600 ° C. or higher cannot be suppressed. If the cap layer is too thick, it will not be p-type.

A preferable range of the oxidation temperature is considered to be about 400 ° C to 650 ° C. At a temperature lower than 400 ° C., the oxidation reaction hardly proceeds. Further, at a temperature higher than 650 ° C., the oxidation reaction proceeds too fast, making it difficult to control the cap layer thickness (control of the oxidation time with a strong oxidizing gas). For example, when the oxidation temperature is 700 ° C., the Zn ₃ N ₂ film having a thickness of 200 nm is oxidized to become ZnO by oxidation for 2 minutes in H ₂ O.

In the sixth to eighth experiments, the Zn ₃ N ₂ single crystal film formed on the a-plane sapphire substrate was oxidized to obtain a ZnO: N single crystal film. However, the ZnO single crystal (and MgZnO single crystal) was obtained. Similarly, it is considered that a ZnO: N single crystal film can be obtained by oxidation with respect to the Zn ₃ N ₂ single crystal film formed above.

As described above, for example, a Zn ₃ N ₂ single crystal film can be grown on the surface of a ZnO single crystal, and the Zn ₃ N ₂ single crystal film is oxidized by oxidizing the Zn ₃ N ₂ single crystal film. Obtainable.

After forming a ZnO film on the surface of the Zn ₃ N ₂ film with a relatively strong oxidizing gas, two-step oxidation is performed to oxidize the remaining Zn ₃ N ₂ film with a relatively weak oxidizing gas. A ZnO: N film having excellent surface flatness and adhesion and p-type conductivity can be produced.

Incidentally, as shown in FIG. 9, _Zn 3 _{N 2} and _Mg 3 _{N 2} are crystalline structures are the same, _Zn 3 in the same manner as the epitaxial growth of the _{N 2,} epitaxial growth of MgZnN with the addition of Mg to the _Zn 3 _{N 2} Is also possible. MgZnO can be produced by oxidizing MgZnN.

  By adding Mg to ZnO to form MgZnO, the band gap can be widened. However, since ZnO has a wurtzite structure and MgO has a rock salt structure, if the Mg composition is too high, phase separation occurs.

In _Mg z _{Zn 1-z} O a Mg composition of MgZnO was stated to z, Mg composition z is preferably set to 0.6 or less to keep the wurtzite structure. In addition, by including Mg composition z = 0, ZnO to which Mg is not added is also included in the notation of Mg _z Zn _1-z O.

Clearly the composition of MgZnN, in the Mg composition indicated as _{y (Mg y Zn 1-y} ) 3 N 2, Mg composition y is obtained by oxidizing this _Mg z _{Zn 1-z} O in the Mg composition z Is basically the same. _Therefore, the estimated upper limit be 0.6 (Mg _{y Zn 1-y)} of ₃ N ₂ Mg composition y. However, it sublimates slightly _{(Mg y Zn 1-y)} 3 N 2 film by oxidizing conditions, since it tends to fly towards the Zn from Mg, obtained by oxidizing _Mg z _{Zn 1-z} O layer of Mg composition z May be slightly higher. In addition, by including Mg composition y = 0, Zn ₃ N ₂ to which Mg is not added is also included in the notation (Mg _y Zn _1-y ) ₃ N ₂ .

  Next, a method for manufacturing a ZnO-based semiconductor light-emitting device according to an application example as a result of the eighth experiment will be described.

FIG. 14A is a schematic cross-sectional view illustrating a structure of a light emitting element of a first application example. On a Zn-faced ZnO (0001) substrate 71 having n-type conductivity, the growth temperature is 300 ° C., the Zn flux is 0.1 nm / s, and the O radical beam irradiation conditions are an RF power of 300 W and an O ₂ flow rate of ₂ sccm. A ZnO buffer layer 72 having a thickness of 30 nm is grown. Then, annealing is performed at 900 ° C. to improve the crystallinity and surface flatness of the ZnO buffer layer 72.

On the ZnO buffer layer 72, the growth temperature is 900 ° C., the Zn flux is 0.3 nm / s, the O radical beam irradiation conditions are an RF power of 250 W, an O ₂ flow rate of 1 sccm, and a 150 nm thick n-type ZnO layer 73. Grow.

On the n-type ZnO layer 73, the growth temperature is 900 ° C., the Zn flux is 0.1 nm / s, the Mg flux is 0.03 nm / s, and the O radical beam irradiation condition is an RF power of 300 W and an O ₂ flow rate of ₂ sccm. As a result, an n-type MgZnO layer 74 having a thickness of 30 nm is grown.

A 10 nm thick ZnO film is grown on the n-type MgZnO layer 74 with a growth temperature of 900 ° C., a Zn flux of 0.1 nm / s, an O radical beam irradiation condition of RF power of 300 W and an O ₂ flow rate of ₂ sccm. Thus, the active layer 75 is formed.

  As shown in FIG. 14B, instead of the ZnO single layer active layer 75, an active layer 75 having a quantum well structure in which MgZnO barrier layers 75b and ZnO well layers 75w are alternately stacked may be formed.

On the active layer 75, the growth temperature is set to 225 ° C., the Zn flux is set to 0.11 nm / s, the N radical beam irradiation condition is set to an RF power of 300 W, an N ₂ flow rate of ₂ sccm, and an Mg beam is also irradiated as necessary. , growing _{(Mg y Zn 1-y)} 3 N 2 (0 ≦ y ≦ 0.6) layer 76a having a thickness of 100 nm. For example, (Mg _0.31 Zn _0.69 ) ₃ N ₂ is obtained with an Mg flux of 0.004 nm / s, and (Mg _0.5 Zn _0.5 ) ₃ with an Mg flux of 0.008 nm / s. N ₂ is obtained.

Then, the substrate is taken out from the MBE chamber, placed in an oxidation heating furnace, heat-treated for 2 minutes at an oxidation temperature of 600 ° C. for example in an H ₂ O gas flow, and then heat-treated for 15 minutes at an oxidation temperature of 600 ° C. for example in an O ₂ gas flow. subjected _{to, (Mg y Zn 1-y} ) 3 and _{N 2 (0 ≦ y ≦ 0.6} ) layer 76a, p-type doped in _{N Mg z Zn 1-z O} (0 ≦ z ≦ 0.6) Change to layer 76.

Thereafter, an n-side electrode 77n is formed on the back surface of the ZnO substrate 71, a p-side electrode 77p is formed on the p-type Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) layer 76, and a p-side electrode is formed. A bonding electrode BE is formed on 77p. The n-side electrode 77n is formed, for example, by laminating an Al layer having a thickness of 500 nm on a Ti layer having a thickness of 10 nm. The p-side electrode 77p is formed, for example, by laminating a 10 nm thick Au layer on a 1 nm thick Ni layer, and the bonding electrode BE is formed of, for example, a 500 nm thick Au layer. After the n-side electrode 77n, the p-side electrode 77p, and the bonding electrode BE are formed, for example, alloying is performed in the atmosphere at 300 ° C. for 1 minute. In this way, the light emitting element of the first application example is formed.

As a modification, after growing an N-doped Mg _a Zn _1-a O (0 ≦ a ≦ 0.6) layer on the active layer as a first p-type ZnO-based semiconductor layer by MBE growth, As a contact layer, Mg _b Zn _1-b ) ₃ N ₂ (0 ≦ b ≦ 0.6) is grown and oxidized to form a Mg _c Zn _1-c O (0 ≦ c ≦ 0.6) layer. A second p-type ZnO-based semiconductor may be formed.

  FIG. 15 is a schematic cross-sectional view showing the structure of a light emitting device of a second application example. An MgO buffer layer 82 having a thickness of 3 nm or more is grown as a polarity control layer on the c-plane sapphire substrate 81 which is an insulating substrate in the same manner as the MgO film 52 in the fifth experiment.

  A ZnO buffer layer 83 is formed on the MgO buffer layer 82 in the same manner as the ZnO buffer layer 72 of the first application example. An n-type ZnO layer 84 is formed on the ZnO buffer layer 83 in the same manner as the n-type ZnO layer 73 of the first application example. An n-type MgZnO layer 85 is formed on the n-type ZnO layer 84 in the same manner as the n-type MgZnO layer 74 of the first application example.

An active layer 86 is formed on the n-type MgZnO layer 85 in the same manner as the active layer 75 of the first application example. On the active layer 86, in the same manner as the p-type Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) layer 76 of the first application example, (M g _y Zn _1-y ) ₃ N ₂ (0 ≦ A p-type Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) layer 87 is formed by oxidation of the y ≦ 0.6) layer.

Since the insulating substrate is used in the second application example, the n-side electrode cannot be taken on the back side of the substrate. Therefore, the point of taking the n-side electrode from above the substrate is different from the electrode forming process of the first application example. The region where the n-side electrode 88n is formed is etched from the upper surface of the p-type Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) layer 87 to a depth at which the n-type ZnO layer 84 is exposed, and the exposed n-type is exposed. An n-side electrode 88n is formed on the ZnO layer 84. Then, the p _- side electrode 88 p is formed on the p-type Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) layer 87, and the bonding electrode BE is formed on the p-side electrode 88. In this way, the light emitting element of the second application example is formed.

In the above experiments and application examples, MBE is exemplified as a method for growing a (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film. However, for example, pulse laser deposition (PLD) ) And other metal deposition methods such as metal organic chemical vapor deposition (MOCVD) could be used.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Zn source gun 3 Mg source gun 4 Ga source gun 5 O source gun 6 N source gun 7 Substrate holder 8 Substrate 9 Thickness meter 10 RHEED gun,
11 Screen 12 Display device 21 a-plane sapphire substrate 31 Zn-plane ZnO substrate 22, 32 Zn ₃ N ₂ film 41 a-plane sapphire substrate 51 c-plane sapphire substrate 52 MgO film 42, 53 low-temperature ZnO buffer layer 43, 54 ZnO film 44, 55 Zn ₃ N ₂ film 61 chamber 62 susceptor 63 sample 64 heater 65a O ₂ source 66a H ₂ O source 71 Zn surface ZnO substrate 81 c surface sapphire substrate 82 MgO buffer layer 72, 83 ZnO buffer layer 73, 84 n-type ZnO layer 74, 85 n-type MgZnO layer 75, 86 Active layer 76, 87 p-type Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) layer 77n, 88n n-side electrode 77p, 88pp p-side electrode BE Bonding electrode

Claims (11)

(A) (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal on a base having a Mg _x Zn _1-x O (0 ≦ x ≦ 0.6) single crystal surface Growing the film;
(B) The above (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film is oxidized to form N-doped Mg _z Zn _1-z O (0 ≦ z ≦ 0.6). And a step of forming a single crystal film. The step (b) performs a first oxidation for oxidizing the (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film with a relatively strong oxidizing gas, 2. The method for manufacturing a ZnO-based semiconductor layer according to claim 1, wherein second oxidation is performed by oxidizing with a relatively weak oxidizing gas. The strong oxidizing gas includes at least one of H ₂ O, ozone, methyl alcohol, ethyl alcohol, and O radical, and the weak oxidizing gas includes O ₂ , N ₂ O, CO ₂ , NO, NO _The method for producing a ZnO-based semiconductor layer according to claim 2, comprising at least one of 2. The first oxidation forms a cap layer by oxidizing the surface of the (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film, and the second oxidation comprises 4. The method for producing a ZnO-based semiconductor layer according to claim 2, wherein a portion remaining inside the (M g _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film is oxidized.   5. The method of manufacturing a ZnO-based semiconductor layer according to claim 4, wherein the first oxidation forms the cap layer having a thickness of 5 nm to 30 nm. The step (b), wherein the _{(Mg y Zn 1-y)} 3 N 2 (0 ≦ y ≦ 0.6) single-crystal film, in any one of claims 1 to 5, oxidation at 650 ° C. or less The manufacturing method of the ZnO type semiconductor layer of description. The Mg _x Zn _1-x O (0 ≦ x ≦ 0.6) single crystal surface is a {0001} plane, and the (M g _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single The surface of the crystal film is a {111} plane, and the surface of the N-doped Mg _z Zn _1-z O (0 ≦ z ≦ 0.6) single crystal film is a {0001} plane. A method for producing a ZnO-based semiconductor layer according to claim 1. Wherein step (a), said _{(Mg y Zn 1-y)} 3 N 2 (0 ≦ y ≦ 0.6) single-crystal film, in any one of claims 1 to 7, is grown at 300 ° C. or less The manufacturing method of the ZnO type semiconductor layer of description. 9. The process according to claim 1, wherein in the step (a), the (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film is grown by MBE. A method for manufacturing a ZnO-based semiconductor layer. (C) growing an n-type ZnO-based semiconductor layer above the semiconductor substrate;
(D) growing a ZnO-based semiconductor active layer on the n-type ZnO-based semiconductor layer;
(E) growing a (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film above the ZnO-based semiconductor active layer;
(F) The (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film is oxidized to form N-doped p-type Mg _z Zn _1-z O (0 ≦ z ≦ 0. 6) A method for manufacturing a ZnO-based semiconductor light-emitting device, which includes a step of forming a single crystal film. The step (f) performs a _first oxidation that oxidizes the (Mg _y Zn _1-y ) ₃ N ₂ (0 ≦ y ≦ 0.6) single crystal film with a relatively strong oxidizing gas, The method for manufacturing a ZnO-based semiconductor light-emitting element according to claim 10, wherein second oxidation is performed by oxidizing with a relatively weak oxidizing gas.