JP2007066986A - Semiconductor light emitting element, package thereof, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting element which allows for crystal growth of an alloy ZnO compound semiconductor having such a composition that is not permitted thermodynamically, and thereby is capable of emitting light in a wide range from ultraviolet to visible range at room temperature, and is thermally stable and has few possibilities of resource depletion, and also to provide a semiconductor light emitting element package and a manufacturing method of the semiconductor light emitting element. <P>SOLUTION: The semiconductor light emitting element comprises a p-type clad layer 11 consisting of a hexagonal-crystal SiC single crystal thin film; and a light emission layer 12 which consists of an alloy ZnO compound semiconductor having a wurtzite structure and a forbidden band width Eg not less than 1.8 eV and less than 3.1 eV, and forms a hetero junction with the clad layer 11. The light emission layer 12 consists of, for example, an n-type Zn<SB>1-x</SB>Cd<SB>x</SB>O(0≤x≤0.7, especially 0.07<x≤0.7). The semiconductor light emitting element also includes an n-type clad layer 13 on the light emission layer 12 and an ohmic contact layer 14 on the n-type clad layer 13, and hence has a double-hetero structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention can emit light at room temperature and can emit light of a desired wavelength in a wide range of ultraviolet to visible range with the same material, and by changing the composition of mixed crystals made of the same material, the ultraviolet light can be changed. The present invention relates to a semiconductor light emitting device mounting body in which a plurality of (a group of) semiconductor light emitting devices emitting light of different wavelengths in a wide visible range are integrated in a hybrid manner, and a method for manufacturing the semiconductor light emitting device.

  Semiconductor light-emitting elements such as light-emitting diodes (LEDs) and semiconductor laser diodes (LDs) preferably emit light in a wide wavelength range. However, as long as a specific forbidden band width (bandgap energy) is used, a single material is wide. It is difficult to cover the wavelength range, and materials having forbidden bandwidths that differ depending on the wavelength are used.

Conventionally, as a blue ultraviolet semiconductor light emitting device, development of a semiconductor light emitting device of a gallium nitride (GaN) / indium gallium nitride (In _1-x Ga _x N) based semiconductor has progressed at an industrial level, and an LED from ultraviolet to red, and from ultraviolet LDs that reach blue are realized and commercially available. Much research has been conducted on the optical properties of In _1-x Ga _x N-based quantum well structures, and it has been observed that the half-width of light emission is wide and the Stokes shift is large. Based on these results, In _1-x Ga _x It has been reported that In composition fluctuation exists in the N quantum well plane, and carriers are localized and emit light due to potential fluctuation caused by In composition fluctuation (the reported In _1-x The relationship between the emission energy of Ga _x N and the Stokes shift is shown in FIG. Furthermore, in particular, white LEDs using In _1-x Ga _x N materials have a problem of causing a color shift due to a change in the concentration of the phosphor of the color conversion material. In addition to Group III-nitride semiconductors such as GaN / In _1-x Ga _x N semiconductors, materials that are being put into practical use as blue ultraviolet semiconductor light emitting devices include Group II-Selenide semiconductors, Group II-sulfides. There are II-VI compound semiconductors such as physical semiconductors and II-oxide semiconductors.

Further, the green to red semiconductor light emitting devices are group III-nitride semiconductors such as gallium nitride (GaN), group III-phosphide semiconductors such as indium phosphorus (InP), and group III-arsenic such as gallium arsenide (GaAs). III-V compound semiconductors such as compound semiconductors. White light can be obtained by combining these light emission colors with the light emission of the blue ultraviolet semiconductor light emitting device. For example, if color mixing is attempted using a blue and green LED using an In _1-x Ga _x N material and a red LED using an (Al _x Ga _1-x ) _y In _1-y P material, the In An LED using a _1-x Ga _x N material has a higher operating voltage and a more complicated circuit configuration than an LED using an (Al _x Ga _1-x ) _y In _1-y P material.

  In addition, it is also possible to obtain white light by emitting light from the phosphor by combining ultraviolet light / purple / blue light emission and a phosphor containing, for example, a rare earth-doped orthosilicate. In any case, many II-VI compound semiconductors and III-V compound semiconductors used for pn junction devices are thermally unstable, and many are likely to be exhausted in terms of resources.

Such a problem is expected to be solved by using a zinc oxide (ZnO) based semiconductor material. Further, as the zinc oxide-based semiconductor material, Zn _1-x Cd _x O has a narrow band gap energy than ZnO, by varying the composition x of Cd, since it is arbitrarily variable emission wavelengths, Zn _1-x Cd It is expected to be suitable as an active layer in a _x O / ZnO heterostructure. ZnO is a hexagonal crystal structure with a wurtzite structure, whereas CdO is a cubic crystal structure with a rock salt structure. Considering that the ionic radii are close to Zn ²⁺ (0.06 nm) and Cd ²⁺ (0.074 nm), it is considered that Cd is replaced with Zn while maintaining the wurtzite structure to some extent. Further, the lattice constant of Zn _1-x Cd _x O having a wurtzite structure is almost the same as that of ZnO. However, there have been reports on the preparation of Zn _1-x Cd _x O thin films by molecular beam epitaxy (MBE), laser excitation MBE, and sputtering, but CdO layer separation has been observed in crystallinity, and Cd separation has occurred. Insufficient for optical application. In particular, the thermodynamic solubility limit of Cd is said to be 2 mol%, and the maximum Cd composition of Zn _1-x Cd _x O has been reported to be about 7% or less (see Non-Patent Document 1). .)

In particular, the technique described in Non-Patent Document 1 is growth on a sapphire substrate, and there is no report example of epitaxial growth of Zn _1-x Cd _x O on a silicon carbide (SiC) substrate.
T. Makino et al., Appl. Phys. Lett, Volume 78 (2001), p. 1237

  Thus, conventionally, it is impossible to realize a plurality of (a group of) semiconductor light-emitting elements that cover a wide spectrum band from room temperature to room temperature at room temperature using the same material, and cover a full-color spectrum band. In order to achieve this, it is necessary to consider the difference in operating voltage due to material characteristics, and there is a problem that the circuit configuration becomes complicated.

In addition, the conventional crystal growth of a ZnO-based compound semiconductor mixed crystal has a maximum Cd composition of about 7% or less, so that only a crystal growth of a limited composition in the vicinity of the ZnO forbidden band width of 3.2 eV can be achieved. For this reason, it was impossible to realize a plurality (a group) of semiconductor light-emitting elements covering a wide spectrum band from the ultraviolet to the visible range at room temperature using the same material called ZnO-based compound semiconductor mixed crystal. In the first place, there are still few examples of producing Zn _1-x Cd _x O thin films by the MOCVD method, and many of the production examples reported so far are those by the laser MBE method or the MBE method. However, the growth temperature of the Zn _1-x Cd _x O thin film by laser MBE or MBE is as high as 600 ° C.

In particular, examples of growth of a Zn _1-x Cd _x O thin film on a SiC substrate and control examples of 7% or more of the Cd composition are not within the scope of the present inventors' knowledge. Further, there are many unclear points regarding the Cd solid solution limit of the wurtzite structure Zn _1-x CdxO thin film and its optical characteristics.

  In view of the above problems, the present invention enables crystal growth of a ZnO-based compound semiconductor mixed crystal having a composition that is thermodynamically unacceptable, and thereby emits light in a wide range from ultraviolet to visible at room temperature. An object of the present invention is to provide a semiconductor light-emitting element, a semiconductor light-emitting element mounting body, and a method for manufacturing the semiconductor light-emitting element that are possible, are thermally stable, and have little risk of resource depletion. In particular, since full-color light emission is made possible by changing the composition of the ZnO-based compound semiconductor mixed crystal, a plurality of (a group of) semiconductor light-emitting elements made of the same material called a ZnO-based compound semiconductor mixed crystal have a full-color spectral band. It is an object of the present invention to provide a plurality of (a group of) semiconductor light emitting elements that cover a full color without any difference in operating voltage.

  In order to achieve the above object, the first aspect of the present invention includes (a) a cladding layer made of a hexagonal SiC single crystal and (b) a wurtzite structure, and a forbidden band width of 1.8 eV or more at room temperature. The gist of the present invention is a semiconductor light-emitting device comprising a ZnO-based compound semiconductor mixed crystal of less than 3.1 eV and including a light-emitting layer that forms a heterojunction with a cladding layer. The limitation to “forbidden band width at room temperature of 1.8 eV or more and less than 3.1 eV” is intended to cover the emission wavelength from red (1.8 eV) to purple (3.1 eV). Does not preclude having a forbidden bandwidth extending to ultraviolet light (3.3 eV). However, when the ZnO-based compound semiconductor mixed crystal has a forbidden band width of less than 1.8 eV at room temperature, it does not tend to have a wurtzite structure.

The second aspect of the present invention comprises (a) a substrate made of a hexagonal single crystal and (b) a hexagonal single crystal thin film having a forbidden band width of 2.8 eV or more at room temperature, and is disposed on the substrate. And a (c) wurtzite structure with a ZnO-based compound semiconductor mixed crystal having a forbidden band width of 1.8 eV or more and less than 3.1 eV at room temperature, and forms a heterojunction with the p-type cladding layer. The gist of the present invention is a semiconductor light emitting device including a light emitting layer. Examples of the “hexagonal single crystal thin film having a forbidden band width of 2.8 eV or more at room temperature” include, for example, 2H—SiC single crystal thin film (Eg = 3.2 to 3.8 eV), 4H—SiC single crystal thin film (Eg = 3.2 to 3.26 eV), 6H—SiC single crystal thin film (Eg = 2.86 to 3.0 eV), and 8H—SiC single crystal thin film (Eg = 2.8 eV) can be used. Furthermore, as “a hexagonal single crystal thin film having a forbidden band width of 2.8 eV or more at room temperature”, a p-type ZnO single crystal thin film (Eg = 3.3 to 3.37 eV) or a p-type GaN single crystal thin film (Eg = 3). .44 to 3.5 eV). On the other hand, as "a substrate made of a hexagonal single crystal", n-type SiC single crystal substrates such as 2H-SiC, 4H-SiC, 6H-SiC, 8H-SiC, n-type ZnO single crystal substrates, n Examples thereof include a type GaN single crystal substrate and an insulating sapphire (Al ₂ O ₃ ) substrate. The p-type SiC clad layer, p-type ZnO clad layer or p-type GaN clad layer is either an n-type SiC single crystal substrate, an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate or an insulating sapphire substrate. It may be epitaxially grown on top. That is, the p-type SiC clad layer, the p-type ZnO clad layer or the p-type GaN clad layer and the n-type SiC single crystal substrate, the n-type ZnO single crystal substrate, the n-type GaN single crystal substrate or the insulating sapphire substrate are optional. Combinations of these are allowed. A p-type SiC clad layer, a p-type ZnO clad layer or a p-type GaN clad layer is epitaxially grown on an n-type SiC single crystal substrate, an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate or an insulating sapphire substrate. Thus, an integrated structure is possible. For example, a first semiconductor light emitting element that emits red light on either an n-type SiC single crystal substrate, an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate, or an insulating sapphire substrate; If the second semiconductor light emitting element that emits light and the third semiconductor light emitting element that emits blue light are monolithically integrated, it is possible to mix red, green, and blue light emitted from one chip. The white semiconductor light emitting device can be provided.

  A third aspect of the present invention is (i) a first semiconductor light emitting device having a light emitting layer having a wurtzite structure and comprising a ZnO-based compound semiconductor mixed crystal having a forbidden band width of 1.8 eV or more and less than 3.1 eV at room temperature. And (b) a wurtzite structure, a ZnO-based compound semiconductor mixed crystal having a forbidden band width of 1.8 eV or more and less than 3.1 eV at room temperature, and a light emitting layer having a light emission wavelength different from that of the first semiconductor light emitting element. The gist of the present invention is a semiconductor light emitting device mounting body including the second semiconductor light emitting device. By arranging the first semiconductor light emitting element and the second semiconductor light emitting element having the light emitting layers having different emission wavelengths from each other, the light emission wavelengths of the first and second semiconductor light emitting elements are arranged. Color mixing is possible. Since the first semiconductor light-emitting element and the second semiconductor light-emitting element are provided, a third semiconductor light-emitting element having a light-emitting layer having a light emission wavelength different from that of the first and second semiconductor light-emitting elements May be added. For example, a first semiconductor light emitting element that emits red light, a second semiconductor light emitting element that emits green light, and a third semiconductor light emitting element that emits blue light are arranged close to each other, and red, green, and blue light are emitted. A semiconductor light emitting device mounting body that emits white light when mixed colors can be provided. Further, if the emission intensity of each of the first semiconductor light emitting element that emits red light, the second semiconductor light emitting element that emits green light, and the third semiconductor light emitting element that emits blue light is adjusted, full color is obtained. It is possible to provide a semiconductor light-emitting element mounting body that emits light of an arbitrary wavelength in the spectral band.

In the fourth aspect of the present invention, (i) a Zn raw material is introduced together with hydrogen radicals on the surface of a p-type SiC single crystal substrate, and an atomic layer of Zn is grown on the surface of the p-type SiC single crystal substrate. And (b) stopping irradiation of hydrogen radicals, introducing Zn raw material and Cd raw material together with oxygen radicals to the surface of the p-type SiC single crystal substrate, and forming a light emitting layer on the surface of the p-type SiC single crystal substrate. And a step of growing Zn _1-x Cd _x O (0.07 <x ≦ 0.7).

  According to the present invention, a semiconductor light emitting device capable of emitting light in a wide range from ultraviolet to visible at room temperature, thermally stable and less likely to be depleted of resources, a semiconductor light emitting device mounting body, and a method for manufacturing a semiconductor light emitting device Can be provided. In particular, by changing the composition of the ZnO-based compound semiconductor mixed crystal, it is possible to prepare a plurality of (a group of) semiconductor light-emitting elements made of the same material as the ZnO-based compound semiconductor mixed crystal so that these full colors can be obtained. The difference in operating voltage between the plurality of (a group of) semiconductor light emitting elements to be covered can be reduced as compared with the case where the semiconductor light emitting elements of completely different materials are combined to cover the full color.

  Next, first to sixth embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The first to sixth embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is The material, shape, structure, arrangement, etc. are not specified below. The technical idea of the present invention can be variously modified within the technical scope described in the claims.

(First embodiment)
As shown in FIG. 1, the semiconductor light emitting device according to the first embodiment of the present invention has a (0001) plane, a clad layer 11 made of hexagonal SiC single crystal, a wurtzite structure, and a forbidden band width. The light emitting layer 12 is made of a ZnO-based compound semiconductor mixed crystal having Eg = 1.8 eV or more and less than 3.1 eV, and forms a heterojunction with the cladding layer 11. The clad layer 11 is a p-type clad layer made of a p-type SiC single crystal having an impurity density of about 6 × 10 ¹⁷ cm ⁻³ to 1 × 10 ¹⁹ cm ⁻³ , but in FIG. 1, 2H—SiC and 4H—SiC are used. , 6H—SiC, 8H—SiC, or other p-type SiC single crystal substrate 11. The ZnO-based compound semiconductor mixed crystal constituting the light emitting layer 12 has an impurity density of about 1 × 10 ¹⁶ cm ⁻³ to 1 × 10 ¹⁸ cm ⁻³ epitaxially grown on the cladding layer 11 made of a SiC single crystal having a (0001) plane. N-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7). An n-type cladding layer made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 12. 13, an ohmic contact layer composed of n impurity concentration ^{1 × 10 17 cm -3 ~5 ×} 10 19 cm -3 of about n-type on the type cladding layer _{13 Mg z Zn 1-z O} (0 ≦ z ≦ 1) 14 is further provided to constitute a double heterostructure. The ohmic contact layer 14 is provided with a cathode (cathode electrode) 15 such as indium (In), In / gold (Au), or Au / germanium (Ge). In FIG. 1, the cathode 15 is provided on a part of the left side of the ohmic contact layer 14, but this is merely an example. For example, a frame-like shape that circulates around the rectangular ohmic contact layer 14 in a plan view, etc. Other shapes may be used. Alternatively, indium oxide (In ₂ O ₃ ) film (ITO) doped with tin (Sn), zinc oxide (ZnO) film (IZO) doped with indium (In), zinc oxide film doped with gallium (Ga) ( The cathode 15 may be provided via a transparent electrode such as GZO), tin oxide (SnO ₂ ), or a zinc oxide film (FTO) doped with fluorine to impart acid resistance. On the other hand, nickel (Ni), aluminum (Al) / Ni, Al / titanium (Ti), Al / tantalum silicide (TaSi ₂ ), titanium carbide is provided on the back surface of the p-type cladding layer made of the p-type SiC single crystal substrate 11. An anode (anode electrode) 18 such as (TiC) / Al is provided.

  In the semiconductor light emitting device according to the first embodiment shown in FIG. 1, the thickness of the p-type cladding layer 11 can be 0.1 mm to 1 mm, preferably about 0.2 mm to 0.8 mm. However, the thickness (for example, about 0.3 mm to 0.6 mm) of a commercially available p-type SiC single crystal substrate may be applied as it is. The thickness of the light emitting layer 12 may be selected from about 5 nm to 400 nm, preferably about 50 nm to 200 nm, and the thickness of the n-type cladding layer 13 may be selected from about 20 nm to 800 nm, preferably about 200 nm to 500 nm. The thickness of the ohmic contact layer 14 may be selected from about 10 nm to 100 nm, preferably about 10 nm to 30 nm. Furthermore, the thickness of the cathode 15 and the anode 18 may be selected from about 100 nm to 2 μm, preferably about 0.5 μm to 2 μm.

FIG. 2 shows the energy band structure of the main part of the semiconductor light emitting device according to the first embodiment of the present invention. In the left side of FIG. 2D and FIG. 2A, the energy band structure of p-type SiC having a forbidden band width Eg = 3.26 eV corresponding to the p-type cladding layer 11 is shown in the center of FIG. FIG. 2B shows an energy band structure of n-type Zn _0.92 Cd _0.08 O having a forbidden band width Eg = 2.8 eV (blue) corresponding to the light emitting layer 12, and the right side of FIG. c) shows an energy band structure of n-type Mg _0.1 Zn _0.9 O corresponding to the n-type cladding layer 13 and having a forbidden band width Eg = 3.65 eV. In the description of FIG. 2, in order to facilitate understanding of the characteristics of the heterojunction, an ideal energy level of the semiconductor heterojunction when no interface state exists at the heterojunction interface is illustrated. In FIG. 2, the electron affinity of _SiC is χ _SiC = 4.2 eV, the electron affinity of Zn _0.92 Cd _0.08 O is χ _ZnCdO = 4.12 eV, and the electron affinity of Mg _0.1 Zn _0.9 O is χ _MgZnO = 3.83 eV.

As shown in FIG. 2, the band discontinuity ΔEc exists in the conduction band at the junction interface between p-type SiC and n-type Zn _0.92 Cd _0.08 O due to the difference in electron affinity χ between the two, and the relationship is as follows. It can be expressed as equation (1).
_{ΔEc = χ SiC -χ ZnCdO = 0.08eV} ... (1)
Furthermore, the _valence band at the junction interface between p-type SiC and n-type Zn _0.92 Cd _0.08 O is
ΔEv = Eg _SiC + ΔEc−Eg _ZnCdO = 0.54 eV (2)
There is a band discontinuity amount ΔEv.

On the other hand, in the conduction band at the junction interface between n-type Zn _0.92 Cd _0.08 O and n-type Mg _0.1 Zn _0.9 O in FIG. 2, there is a band discontinuity (energy barrier) ΔEc due to the difference in electron affinity χ between the two. However, the illustration is omitted. The band discontinuity amount ΔEc can be expressed as the following formula (3).
_{ΔEc = χ ZnCdO -χ MgZnO = 0.29eV} ... (3)
Furthermore, the _valence band at the junction interface between p-type SiC and n-type Zn _0.92 Cd _0.08 O is
ΔEv = Eg _ZnCdO + ΔEc−Eg _MgZnO = −0.56 eV (4)
There is a band discontinuity amount ΔEv.

As shown in FIG. 3, the photoluminescence (PL) spectrum of the wurtzite structure Zn _1-x Cd _x O thin film at room temperature is ₁ from x = 0.7 from 3.28 ev of ZnO as the Cd composition x increases. Shift to low energy side to .73 eV. In all the spectra in the range of Cd composition x = 0 to 0.7, light emission from a deep level is not observed. From this, it is understood that light emission from the wurtzite structure Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) thin film covers the entire visible range from the near ultraviolet, and is useful as a semiconductor light emitting device. it can. The crystal structure of the Zn _1-x Cd _x O thin film is strongly oriented along the w-axis of the wurtzite structure in the range of 0 ≦ x ≦ 0.7 from the XRD measurement, and the (0002) peak decreases toward the lower angle as the Cd composition increases. shift. When the Cd composition is greater than 0.7, the (0002) peak disappears and the (220) and (111) peaks of the rock salt structure derived from CdO appear.

FIG. 4 shows the Cd composition of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) thin film at room temperature, the forbidden band width (bandgap energy) obtained from the optical absorption termination, and the forbidden value obtained from the PL emission energy. The relationship with the band width (band gap energy) is shown. The optical absorption edge is linearly shifted to the low energy side as the Cd composition increases. The PL peak in ZnO (x = 0) showed the same energy as the absorption edge, but the mixed crystal Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) was Stokes shifted and moved to a lower energy side from the absorption edge. An emission peak is shown. As shown in FIG. 4, the band gap energy of the wurtzite structure Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) mixed crystal can be arbitrarily controlled in a wide wavelength range from 1.8 eV to 3.3 eV. I understand.

MgO has a band gap energy of 7.8 eV, and its crystal structure is an oxide semiconductor having a rock salt structure. The ion radius of Mg ²⁺ is 0.057 nm, which is very close to the ion radius of Zn ²⁺ of 0.06 nm. Mg _z Zn _1-z O is a ternary mixed crystal compound semiconductor in which Mg is added to ZnO. By controlling the composition z of Mg from ZnO to MgO, as shown in FIG. The lattice constant can be changed. Fig. 5 shows the results of Matsumoto et al. (○) described in Japanese Journal of Applied Physics, Volume 38 (1999), page L603 (○), Applied Physics Letter ( (Appl. Phys. Lett), Vol. 79 (2001), p. 2022, the results of WIPark et al. (▼) and Japanese Journal of Applied Physics (Jpn.J.Appl.Phys.) The result (□) of Takagi et al. Described in Volume 42 (2003), page L401 is also shown.

Figure 6 shows the relationship between band gap and lattice constant of the c-axis direction for Mg _z Zn _1-z O mixed crystal and Zn _1-x Cd _x O mixed crystal. Makino et al. Reported that the change of the a-axis length in the Mg _z Zn _1-z O / Zn _1-x Cd _x O (system is slightly larger in both mixed crystals (Applied Physics Letter (Appl. Phys. Lett) 76 Volume (2000) 3549 see page.). if you look at Figure 6, to perform the lattice matching growth in _{Mg z Zn 1-z O /} Zn 1-x Cd x O ( system heterostructures growth In view of the fact that lattice mismatch can lead to strain and piezo electric fields, it can be advantageous compared to In _1-x Ga _x N / Al _1-x Ga _x N heterostructures. I understand.

According to the semiconductor light emitting device according to the first embodiment of the present invention, light emission in a wide spectral range from red (1.8 eV) to purple (3.1 eV) and further ultraviolet light (3.3 eV) at room temperature. Therefore, it is possible to provide a semiconductor light emitting element that is thermally stable and has little risk of resource depletion. In particular, by changing the composition x of Zn _1-x Cd _x O (0 ≦ x ≦ 0.7), full-color light emission is made possible, so that the full-color spectrum band can be changed to Zn _1-x Cd _x O (0 Since it is possible to provide a plurality (a group) of semiconductor light-emitting elements made of the same material such that ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7, a plurality (a group) of semiconductor light-emitting elements covering full color The difference between the operating voltages can be reduced as compared with a case where a full color is covered by combining semiconductor light emitting elements of completely different materials.

<Remote plasma excitation MOCVD equipment>
In the method for manufacturing a semiconductor light emitting device according to the first embodiment of the present invention, Cd exceeding the thermodynamic solubility limit is introduced into the Zn _1-x Cd _x O thin film to be the light emitting layer 12, and Cd In order to arbitrarily control the composition, it is necessary to introduce radicals into the reaction process to promote surface reactions and to perform crystal growth with a high degree of non-equilibrium at low temperatures.

A remote plasma excitation MOCVD method will be described as an example of a method for introducing a radical into this reaction process to promote the decomposition of the organic metal and enabling crystal growth at a low temperature. That is, the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7) light emitting layer 12 is grown on the p-type SiC single crystal substrate 11 shown in FIG. At this time, the remote plasma excitation MOCVD apparatus shown in FIG. 7 is used to perform crystal growth at a low temperature and with a high degree of non-equilibrium to introduce Cd exceeding the thermodynamic solid solution limit into the Zn _1-x Cd _x O thin film. .

In the conventional MOCVD method, since it is necessary to decompose the raw material with heat, the substrate temperature is determined by the raw material, and there is a limit to lowering the temperature. In the remote plasma excitation MOCVD apparatus, a plasma generation part and a transport part are added to a conventional MOCVD apparatus, radicals are introduced into the reaction process to promote decomposition of the organic metal, and crystal growth at low temperature is possible. That is, in the remote plasma excitation MOCVD apparatus, oxygen (O ₂ ), hydrogen (H ₂ ), etc. are converted into plasma, and necessary excitation species such as neutral atom radicals are taken out and used for the thin film growth reaction. In this remote plasma excitation MOCVD apparatus, the growth pressure is reduced from normal pressure to several pressures (several hPa) in the MOCVD method that is generally performed. It is characteristic that the reaction in the gas phase can be controlled.

  For this reason, as shown in FIG. 7, a plasma generator 61 is arranged in a place different from the stainless steel chamber 66 that is a reaction vessel, and oxygen, hydrogen, and helium (He) are converted into plasma by the plasma generator 61 to generate ions. Among the electrons, radicals, and light, neutral atom radicals (oxygen radicals, hydrogen radicals, helium radicals) having a relatively long lifetime are transported to the stainless steel chamber 66 and used for the decomposition reaction of the raw material. As shown in FIG. 7, a gas flow guide tube 65 made of quartz glass is attached inside the vertical stainless steel chamber 66 through a flange 67 that seals the upper portion of the stainless steel chamber 66. The stainless steel chamber 66 is water cooled by cooling water 68. The p-type SiC single crystal substrate 11 is mounted on a SiC-coated carbon susceptor 72 and is placed horizontally at a position about 10 cm below the inlet of the source gas. The substrate holder 69 on which the carbon susceptor 72 is mounted has a built-in resistance heater 73, and temperature control is performed by a thermocouple provided on the opposite side to the p-type SiC single crystal substrate 11. The substrate holder 69 is provided with a rotation mechanism, for example, to grow while rotating the p-type SiC single crystal substrate 11 at about 25 rpm. Although not shown, the remote plasma excitation MOCVD apparatus includes a load lock mechanism, and the stainless steel chamber 66 is always shut off from the outside air.

  As the plasma generator 61, for example, a hollow-cathode-jet type plasma generator of φ35 mm borosilicate glass or quartz glass tube can be employed. However, as the plasma generator 61, an inductively coupled plasma (ICP) method, a microwave induction plasma (MIP) method, a laser induced plasma (LIP) method, or a parallel plate method may be used in addition to the hollow cathode method shown in FIG. The plasma generator 61 may be disposed, for example, approximately 20 cm from the p-type SiC single crystal substrate 11. For example, a high frequency of 13.56 MHz is applied to the plasma generator 61 with a power of 10 W or more to generate plasma, and radicals are introduced onto the p-type SiC single crystal substrate 11 through the transport tube. The stainless steel chamber 66 and the radical transport pipe are connected by a metal flange. In order to prevent radicals from recombining and disappearing, an inner pipe made of quartz glass is provided in the flange so that the radical being transported directly on the metal surface. It is preferable to design so that it does not touch.

For epitaxial growth of Zn _1-x Cd _x O, diethyl zinc (DEZn) and dimethyl cadmium (DMCd) are used as group II materials, and oxygen gas is used as group VI materials as source materials. On the other hand, the epitaxial growth of Mg _z Zn _1-z O, as a raw material, diethylzinc in II group material (DEZn) and bis-ethyl cyclopentadienyl magnesium (EtCp ₂ Mg), the oxygen gas to the VI group material use. There is an example in which Cp ₂ Mg or MeCp ₂ Mg is used as the Mg precursor raw material in the MOCVD method, but there is no example of producing Mg _z Zn _1-z O using EtCp ₂ Mg. In the first embodiment, this is adopted as a stable growth method. Organic raw materials DEZn, EtCp ₂ Mg, and DMCd are liquid at room temperature. For this reason, DEZn, EtCp ₂ Mg, and DMCd are introduced into the stainless steel chamber 66 through a transport pipe provided in the flange 67 at the top of the chamber by bubbling with a carrier gas. The EtCp ₂ Mg material line is provided with a line heater to prevent solidification in the transport pipe during material transportation. Since DEZn and DMCd have different operating temperatures, a separate line (transport pipe) is provided for EtCp ₂ Mg for introducing the chamber. The composition x of the Zn _1-x Cd _x O thin film can be controlled by manipulating the flow rate of the group II raw material, and the composition x may be identified by EPMA. Zn metal and CdTe crystal may be used for reference of composition measurement at the time of EPMA identification.

  The growth rate during the growth is that the light reflected from the surface of the p-type SiC single crystal substrate 11 and the film surface is irradiated with light from a light source 62 such as a He—Ne laser from a quartz window 64b attached to the stainless steel chamber 66. Light is received by a photodetector 63 such as a photodiode cell, and measurement is performed in-situ using the interference. For the calibration of the film thickness, the film thickness is measured using a stylus type surface shape measuring apparatus after growth. In order to observe the plasma state during growth, the emission of plasma species is observed from a quartz observation window (observation window) 64a attached to the flange 67 at the upper part of the chamber using a spectrometer.

<Method for Manufacturing Semiconductor Light Emitting Element According to First Embodiment>
Next, a method for manufacturing the semiconductor light emitting element according to the first embodiment of the present invention will be described with reference to FIG. The semiconductor light emitting device manufacturing method described below is an example, and it is needless to say that the semiconductor light emitting device can be realized by various other manufacturing methods including this modification. For example, in the following description, remote plasma excitation shown in FIG. 7 is used to introduce Cd beyond the thermodynamic solid solution limit in the production of a Zn _1-x Cd _x O thin film on a p-type SiC single crystal substrate 11. Although the case where the MOCVD apparatus is used will be described, radicals introduced into the reaction process at the time of preparing the Zn _1-x Cd _x O thin film may be other than the remote plasma excitation MOCVD apparatus such as ultraviolet excitation.

  (A) First, the p-type SiC single crystal substrate 11 having a plane orientation (0001) plane is washed with an organic solvent such as acetone or methanol. Then, after ultrasonically cleaning with ultrapure water, it is blown with high purity nitrogen or the like and dried. Thereafter, the surface of the p-type SiC single crystal substrate 11 is etched with molten NaOH (500 degrees) and washed (rinsed) with pure water. Then, after etching with 5% to 100% (preferably 5 to 20%) diluted hydrofluoric acid (etching the oxide layer) and washing with pure water, the SiC coating provided in the stainless steel chamber 66 shown in FIG. It is mounted on the carbon susceptor 72. The carbon susceptor 72 is mounted on the substrate holder 69 so that the carbon susceptor 72 is positioned about 10 cm below the introduction port of the raw material gas.

(B) After setting the p-type SiC single crystal substrate 11 on the carbon susceptor 72, the inside of the stainless steel chamber 66 is evacuated to about 10 ⁻² Pa to 10 ⁻⁸ Pa and heated to a substrate temperature of 600 ° C. Then, hydrogen (H ₂ ) gas is introduced so that the chamber temperature becomes 13 Pa to 1.3 Pa at a substrate temperature of 600 ° C., and hydrogen radicals are removed in a hydrogen atmosphere for at least 45 minutes, preferably about 1 hour. Irradiate and clean the surface of the p-type SiC single crystal substrate 11 with hydrogen radicals.

  (C) Thereafter, the substrate temperature is set to an optimum substrate temperature of about 300 ° C. to 600 ° C. (may be 300 ° C. or less depending on the case), DEZn gas is introduced into the surface of the p-type SiC single crystal substrate 11 and the Zn raw material is used. Then, at least one atomic layer, preferably almost one atomic layer, is grown on the surface of the p-type SiC single crystal substrate 11 by irradiation with hydrogen radicals.

(D) Thereafter, irradiation with hydrogen radicals is stopped, Zn raw material (DEZn) and Cd raw material (DMCd) are introduced into the surface of the p-type SiC single crystal substrate 11, and oxygen radicals are irradiated to form a p-type SiC single crystal substrate. As shown in FIG. 8A, Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) to be the light-emitting layer 12 is grown on the surface of 11. The Cd composition x can be controlled by changing the flow ratio of the Zn raw material (DEZn) and the Cd raw material (DMCd). Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, in particular 0.07 <x ≦ 0.7) growth of the Zn source (DEZn) and Cd source (DMCd) is the substrate surface (chemical reaction region) ) Are combined in the same line and combined with oxygen radicals in a hydrogen gas atmosphere to cause a chemical reaction. At this time, it is preferable to set it as 10 cc / min or more of hydrogen gas with respect to the oxygen flow rate for oxygen radicals of 5 cc / min. The electrical conductivity (resistivity) of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) film is not limited to the substrate temperature, but is a group VI material in terms of moles. If the / II group raw material ratio is 60 or less, the resistivity decreases. On the other hand, if the VI group / II group ratio is 80 or more, the resistance is increased. In the region of 60 <VI group material / II group material <80, the electrical conductivity (resistivity) can be controlled by the substrate temperature. For example, the substrate temperature 400 ℃, 300Ω-cm (impurity concentration 5 × 10 ¹⁵ cm ^-3) about, the substrate temperature 500 ℃, 30Ω-cm (impurity density 2 × 10 ¹⁷ cm ^-3), the substrate temperature 600 ° C. , 0.1 Ω-cm (impurity density 3 × 10 ¹⁸ cm ⁻³ ), the semiconductor light emitting device manufacturing method according to the first embodiment grows at a substrate temperature of 400 ° C.

(E) Further, after growing Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7), the Zn raw material (DEZn), Mg at a substrate temperature of 400 ° C. A raw material (EtCp ₂ Mg) is introduced into the surface of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) film and irradiated with oxygen radicals to form the n-type cladding layer 13 on the surface of the light emitting layer 12. _{mg z Zn 1-z O (} 0 ≦ z ≦ 1) is grown. The composition z of the Mg _z Zn _1-z O (0 ≦ z ≦ 1) thin film can be controlled by changing the flow ratio of the Zn source (DEZn) and the Mg source (EtCp ₂ Mg). Similar to the growth of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) film, the growth rate of the Mg _z Zn _1-z O (0 ≦ z ≦ 1) film is 5 cc / min for the oxygen radical oxygen flow rate. The hydrogen gas is preferably 10 cc / min or more. Further, after growing Mg _z Zn _1-z O (0 ≦ z ≦ 1) to be the n-type cladding layer 13, the substrate temperature is raised to 600 ° C., and Zn source (DEZn), Mg source (EtCp ₂ Mg) Is introduced into the surface of the n-type cladding layer 13 and irradiated with oxygen radicals. As shown in FIG. 8B, the surface of the n-type cladding layer 13 is coated with Mg _z Zn _1-z O serving as an ohmic contact layer 14. Growing (0 ≦ z ≦ 1). Similar to the growth of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) film, the electrical conductivity (resistivity) is also increased in the growth of the Mg _z Zn _1-z O (0 ≦ z ≦ 1) film. Since it can be controlled by the substrate temperature, by increasing the substrate temperature to 600 ° C., an n-type Mg _z Zn _1-z O (0) having an impurity density of about 2 × 10 ¹⁸ cm ^{−3 to} 5 × 10 ¹⁹ cm ^−3. ≦ z ≦ 1) A film can be grown. Furthermore, the resistivity may be decreased by setting the VI group / II group ratio to 60 or less in terms of moles.

(F) Next, after the photoresist 16 is applied to the entire surface of the ohmic contact layer 14, the photoresist 16 is patterned by a normal photolithography technique to form a lift-off mask. As shown in FIG. 8C, a metal film 17 such as In, In / Au, or Au / Ge is deposited through the lift-off mask 16 by a vacuum evaporation method, a sputtering method, or the like. Then, if the lift-off mask 16 is removed, the cathode (cathode electrode) 15 as shown in FIG. 1 is patterned. On the other hand, a metal film such as Ni, Al / Ni, Al / Ti, Al / TaSi ₂ , and TiC / Al is deposited on the entire back surface of the p-type SiC single crystal substrate 11 by a vacuum evaporation method, a sputtering method, or the like. . In FIG. 1, the anode (anode electrode) 18 is patterned so as to be localized on the left side. However, if light is not extracted from the back side of the p-type SiC single crystal substrate 11, the p-type SiC single crystal substrate 11 is used. A metal film may be deposited on the entire back surface of the substrate to form the anode 18 having a large area. Thereafter, heat treatment (sintering) is performed to reduce the contact resistance of the cathode 15 and the anode 18. Finally, the semiconductor light emitting device shown in FIG. 1 is completed by cleaving into a rectangular shape of a predetermined size such as 300 μm × 300 μm to 1.5 mm × 1.5 mm or cutting with a diamond blade or the like. The anode 18 may be formed after the commercially available p-type SiC single crystal substrate 11 having a thickness of about 0.3 mm to 0.6 mm is thinned to about 0.1 mm to 0.2 mm by polishing.

According to the method for manufacturing a semiconductor light emitting device according to the first embodiment of the present invention, a wide spectrum of red light (1.8 eV) to purple (3.1 eV) and further ultraviolet light (3.3 eV) at room temperature. A semiconductor light emitting device that can emit light in a range, is thermally stable, and has little risk of resource depletion can be easily manufactured. In particular, the remote plasma-excited MOCVD method is used to introduce radicals into the reaction process to promote surface reaction and to perform crystal growth with a high degree of non-equilibrium at low temperatures. By changing the flow ratio of Cd, Cd exceeding the thermodynamic solid solution limit can be introduced into the Zn _1-x Cd _x O thin film to be the light emitting layer 12, and the composition of Cd can be arbitrarily controlled. In this way, by controlling the composition x of Zn _1-x Cd _x O (0 ≦ x ≦ 0.7), a plurality (a group) of semiconductor light-emitting elements that enable full-color light emission can be manufactured. As a result, a plurality of (a group of) semiconductor light emitting elements made of the same material with a full color spectral band of Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7). The difference in operating voltage between a plurality of (a group of) semiconductor light emitting elements covering a full color can be reduced as compared with a case where a full color is covered by combining semiconductor light emitting elements of completely different materials. Since it is easy, the circuit configuration is simplified.

(Second Embodiment)
As shown in FIG. 9, the semiconductor light emitting device according to the second embodiment of the present invention has a cladding layer 11 made of a hexagonal SiC single crystal and a wurtzite structure, and a forbidden band width Eg = 1.8 eV or more. The light emitting layer 21 is made of a ZnO-based compound semiconductor mixed crystal of less than 3.1 eV and forms a heterojunction with the cladding layer 11. Similar to the semiconductor light emitting device according to the first embodiment, the cladding layer 11 has a plane orientation (0001) plane and a p-type SiC having an impurity density of about 6 × 10 ¹⁷ cm ⁻³ to 1 × 10 ¹⁹ cm ^−3. This is a p-type cladding layer made of a single crystal substrate, and in FIG. 9, is composed of a p-type SiC single crystal substrate 11 such as 2H—SiC, 4H—SiC, 6H—SiC, or 8H—SiC.

However, the ZnO-based compound semiconductor mixed crystal constituting the light emitting layer 21 is an n-type Zn _1-x Cu _x O (0 ≦ x ≦ 1) having an impurity density of about 1 × 10 ¹⁶ cm ⁻³ to 1 × 10 ¹⁸ cm ^−3. This is different from the semiconductor light emitting device according to the first embodiment. Other structural features, that is, n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ on the light emitting layer 21. N-type cladding layer 13 and n-type Mg _z Zn _1-z O (0 ≦ z ≦ n) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13. The ohmic contact layer 14 is further provided with an ohmic contact layer 14 to form a double heterostructure. The ohmic contact layer 14 includes a cathode made of indium (In), In / gold (Au), Au / germanium (Ge), or the like. Further, nickel (Ni), aluminum (Al) / Ni, and Al / titanium (Ti) are provided on the back surface of the p-type cladding layer made of the p-type SiC single crystal substrate 11 in that (cathode electrode) 15 is provided. , Al / tantalum silicide (TaSi _2), Titanium (TiC) / Al anode point (anode electrode) 18 is provided such as is similar to the semiconductor light emitting device according to the first embodiment. Moreover, since the thickness of each layer, such as the thickness of the light emitting layer 21, is the same as that of the semiconductor light emitting device according to the first embodiment, a duplicate description is omitted. Furthermore, the energy band structure of the main part of the semiconductor light emitting device according to the second embodiment of the present invention is basically the same as that in FIG.

According to the semiconductor light emitting device according to the second embodiment of the present invention, the forbidden band width Eg of CuO at room temperature is about 1.2 eV. Therefore, by changing the composition x of Cu, red (1 .8 eV) to purple (3.1 eV), and can emit light in a wider spectral range of ultraviolet light (3.3 eV), and can provide a semiconductor light emitting device that is thermally stable and has little risk of resource depletion. In particular, by changing the composition x of Zn _1-x Cu _x O (0 ≦ x ≦ 1), full-color light emission is made possible, so that the full-color spectrum band can be changed to Zn _1-x Cu _x O (0 ≦ x Since it is possible to provide a plurality (a group) of semiconductor light emitting elements made of the same material of ≦ 1), a difference in operating voltage between each of the plurality of (a group of) semiconductor light emitting elements covering the full color is completely different. It can be made smaller compared to the case where the full color is covered by combining.

The method for manufacturing a semiconductor light emitting device according to the second embodiment of the present invention is basically the same as the first method except that a Zn _1-x Cu _x O thin film is epitaxially grown on the p-type SiC single crystal substrate 11. It can be manufactured by a method similar to the method for manufacturing the semiconductor light emitting device according to the embodiment. In the epitaxial growth of a Zn _1-x Cu _x O thin film, DEZn gas is introduced into the surface of the p-type SiC single crystal substrate 11, a Zn raw material is supplied, and an atomic layer of Zn is formed on the p-type SiC single crystal substrate 11 by hydrogen radical irradiation. After growing at least one atomic layer, preferably approximately one atomic layer on the surface, a Zn raw material and a Cu raw material may be introduced into the surface of the p-type SiC single crystal substrate 11 and irradiated with oxygen radicals. DEZn is suitable as the Zn raw material, and copper (II) 2,2,6,6-tetramethyl-3,5-heptanedionate (2,2,6,6-tetramethyl-3) is suitable as the Cu raw material. , 5-heptanedione copper beta-diketonate: Cu (thd) 2) or copper (II) 2,4-pentanedionate copper can be used. The Cu composition x can be controlled by changing the flow rate ratio between the Zn raw material and the Cu raw material.

(Third embodiment)
As shown in FIG. 10, the semiconductor light emitting device according to the third embodiment of the present invention has a clad layer 11 made of a hexagonal SiC single crystal and a wurtzite structure, and a forbidden band width Eg = 1.8 eV or more. The light emitting layer 22 is made of a ZnO-based compound semiconductor mixed crystal of less than 3.1 eV and forms a heterojunction with the cladding layer 11. As in the semiconductor light emitting devices according to the first and second embodiments, the clad layer 11 has a p-axis with an impurity density of about 6 × 10 ¹⁷ cm ⁻³ to 1 × 10 ¹⁹ cm ⁻³ in the plane orientation (0001) plane. The ZnO-based compound semiconductor mixed crystal constituting the light emitting layer 22 is a p-type having an impurity density of about 1 × 10 ¹⁶ cm ⁻³ to 1 × 10 ¹⁸ cm ^−3. It differs from the semiconductor light emitting device according to the first and second embodiments in that Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7).

Another feature is that n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 22. From the n-type cladding layer 13 and n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13. The ohmic contact layer 14 is further provided to form a double heterostructure, the ohmic contact layer 14 is provided with a cathode (cathode electrode) 15 such as In, and the p-type SiC single crystal substrate 11 is used. The thickness of each layer such as the anode (anode electrode) 18 such as Ni and the thickness of the light emitting layer 22 is the same as that of the first and second embodiments. This is the same as the semiconductor light emitting device, and a duplicate description is omitted.

FIG. 11 shows the energy band structure of the main part of the semiconductor light emitting device according to the third embodiment of the present invention. 11 shows the energy band structure of p-type SiC having a forbidden band width Eg = 3.26 eV corresponding to the p-type cladding layer 11, and the forbidden band width Eg corresponding to the light emitting layer 22 in the center of FIG. = 2.8 eV (blue) p-type Zn _0.92 Cd _0.08 O energy band structure, and on the right side of FIG. 11, the n-type Mg _0.1 Zn having a forbidden band width Eg = 3.65 eV corresponding to the n-type cladding layer 13 The energy band structure of _0.9 O is shown. In the description of FIG. 11, in order to facilitate understanding of the characteristics of the heterojunction, an ideal energy level of the semiconductor heterojunction when no interface state exists at the heterojunction interface is illustrated. In FIG. 11, the electron affinity of _SiC is χ _SiC = 4.2 eV, the electron affinity of Zn _0.92 Cd _0.08 O is χ _ZnCdO = 4.12 eV, and the electron affinity of Mg _0.1 Zn _0.9 O is χ _MgZnO = 3.83 eV.

As shown in FIG. 11, there is a band discontinuity ΔEc in the conduction band at the junction interface between p-type SiC and p-type Zn _0.92 Cd _0.08 O due to the difference in electron affinity χ between the two, and p-type SiC. There is also a band discontinuity ΔEv in the valence band at the junction interface between p-type Zn _0.92 Cd _0.08 O. Furthermore, in the conduction band at the junction interface between p-type Zn _0.92 Cd _0.08 O and n-type Mg _0.1 Zn _0.9 O in FIG. 11, there is a band discontinuity (energy barrier) ΔEc due to the difference in electron affinity χ between the two. The band discontinuity ΔEv also exists in the valence band at the junction interface between p-type SiC and p-type Zn _0.92 Cd _0.08 O.

According to the semiconductor light emitting device of the third embodiment of the present invention, light emission in a wide spectral range from red (1.8 eV) to purple (3.1 eV) and further ultraviolet light (3.3 eV) at room temperature. Therefore, it is possible to provide a semiconductor light emitting element that is thermally stable and has little risk of resource depletion. In particular, by changing the p-type Zn _1-x Cd _x composition x of O (0 ≦ x ≦ 0.7) , since the enabling full-color emission, the spectrum band of full color, p-type Zn _1-x Cd _Since a plurality of (a group of) semiconductor light-emitting elements made of the same material _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7) can be provided, ) The difference in operating voltage between the semiconductor light emitting elements can be reduced as compared with a case where a full color is covered by combining semiconductor light emitting elements of completely different materials.

The semiconductor light emitting device manufacturing method according to the third embodiment of the present invention is basically the semiconductor light emitting device according to the first embodiment except that a p-type Zn _1-x Cd _x O thin film is epitaxially grown. This is the same as the device manufacturing method. For epitaxial growth of a p-type Zn _1-x Cd _x O thin film, Zn raw material (DEZn) and Cd raw material (DMCd) are introduced into the surface of the p-type SiC single crystal substrate 11 and irradiated with oxygen radicals to form a p-type SiC single crystal. When growing Zn _{1 -x} Cd _x O (0 ≦ x ≦ 0.7) to be the light emitting layer 22 on the surface of the substrate 11, ammonia (NH ₃ ), phosphine (PH ₃ ), Arsine (AsH ₃ ) or the like may be used.

(Fourth embodiment)
As shown in FIG. 12, the semiconductor light emitting device according to the fourth embodiment of the present invention includes a substrate 32 made of a hexagonal single crystal and a hexagonal single crystal having a forbidden band width Eg of 2.8 eV or more. A clad layer 41 made of a thin film and a wurtzite structure and a ZnO-based compound semiconductor mixed crystal having a forbidden band width Eg = 1.8 eV or more and less than 3.1 eV and heterogeneous with the clad layer 41. And a light emitting layer 12 forming a junction. FIG. 12 illustrates a case where a p-type SiC single crystal thin film having an impurity density of about 6 × 10 ¹⁷ cm ⁻³ to 1 × 10 ¹⁹ cm ⁻³ is used as the p-type cladding layer 41. Is not limited to a p-type SiC single crystal thin film, but a p-type ZnO single crystal thin film (Eg = 3.3 to 3.37 eV) or a p-type GaN single crystal thin film (Eg = 3.3 to 3.37 eV) as shown in FIGS. Eg = 3.44 to 3.5 eV). As a p-type SiC single crystal thin film having a wurtzite structure, 2H—SiC single crystal thin film (Eg = 3.2 to 3.8 eV), 4H—SiC single crystal thin film (Eg = 3.2 to 3.26 eV), 6H A SiC single crystal thin film (Eg = 2.86 to 3.0 eV) or an 8H—SiC single crystal thin film (Eg = 2.8 eV) can be used.

The substrate 32 is an n-type SiC single crystal substrate such as 2H—SiC, 4H—SiC, 6H—SiC, and 8H—SiC having a plane orientation (0001) plane. Without being limited thereto, an n-type ZnO single crystal substrate with a plane orientation (0001) plane, an n-type GaN single crystal substrate with a plane orientation (0001) plane, a plane orientation (0001) plane, a (12-20) plane, (01- 12) An insulating sapphire (Al ₂ O ₃ ) substrate may be used.

The ZnO-based compound semiconductor mixed crystal constituting the light emitting layer 12 is an n-type having an impurity density of about 1 × 10 ¹⁶ cm ⁻³ to 1 × 10 ¹⁸ cm ⁻³ , similar to the semiconductor light emitting device according to the first embodiment. Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7).

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 12. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. Furthermore, the semiconductor device according to the first embodiment is that the double heterostructure is provided and the ohmic contact layer 14 is provided with a cathode (cathode electrode) 15 made of a metal thin film such as In. The same as the light emitting element.

However, the anode (anode electrode) 18 reaches the surface of the p-type cladding layer 41 through the ohmic contact layer 14, the n-type cladding layer 13, and the light emitting layer 12 instead of the back surface of the n-type SiC single crystal substrate 32. The semiconductor light emitting device according to the first embodiment is different from the semiconductor light emitting device according to the first embodiment in that the groove is provided at the bottom of the groove (step). However, the material of the anode (anode electrode) 18 is a metal material such as Ni, Al / Ni, Al / Ti, Al / TaSi ₂ , TiC / Al, etc., similar to the semiconductor light emitting device according to the first embodiment. Can be adopted.

  In the semiconductor light emitting device according to the fourth embodiment shown in FIG. 12, the thickness of the substrate 32 can be 0.1 mm to 1 mm, preferably about 0.2 mm to 0.8 mm. Specifically, The thickness of a commercially available substrate (for example, about 0.3 mm to 0.6 mm) may be applied as it is. The thickness of the p-type cladding layer 41 may be selected from about 20 nm to 800 nm, preferably about 200 nm to 500 nm. The thickness of the light emitting layer 12 may be selected from about 5 nm to 400 nm, preferably about 50 nm to 200 nm. The thickness of the n-type cladding layer 13 may be selected from about 20 nm to 800 nm, preferably about 200 nm to 500 nm, and the thickness of the ohmic contact layer 14 may be selected from about 10 nm to 100 nm, preferably about 10 nm to 30 nm. Furthermore, the thickness of the cathode 15 and the anode 18 may be selected from about 100 nm to 2 μm, preferably about 0.5 μm to 2 μm.

  The energy band structure of the main part of the semiconductor light emitting device according to the fourth embodiment of the present invention is exactly the same as the energy band structure of the main part of the semiconductor light emitting device according to the first embodiment shown in FIG. Because of this, redundant description is omitted.

According to the semiconductor light emitting device of the fourth embodiment of the present invention, light emission in a wide spectral range of red light (1.8 eV) to purple (3.1 eV) and further ultraviolet light (3.3 eV) at room temperature. Therefore, it is possible to provide a semiconductor light emitting element that is thermally stable and has little risk of resource depletion. In particular, Zn _1-x Cd _x by changing the composition x of O (0 ≦ x ≦ 0.7) , since the enabling full-color emission, the spectrum band of the _{full-color, Zn 1-x Cd x O} (0 Since it is possible to provide a plurality (a group) of semiconductor light-emitting elements made of the same material such that ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7, a plurality of (a group of) semiconductor light-emitting elements covering a full color The difference between the operating voltages can be reduced as compared with the case where a full color is covered by combining semiconductor light emitting elements of completely different materials. In particular, since the anode 18 is formed on the surface of the p-type cladding layer 41, the n-type SiC single crystal substrate 32 may be a substrate with a high specific resistance, and the degree of freedom of substrate selection increases.

  Furthermore, a p-type SiC clad layer, a p-type ZnO clad layer or a p-type GaN clad layer is formed on an n-type SiC single crystal substrate, an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate or an insulating sapphire substrate. By epitaxial growth, an integrated structure is possible. For example, a first semiconductor light emitting element that emits red light on either an n-type SiC single crystal substrate, an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate, or an insulating sapphire substrate; If the second semiconductor light emitting element that emits light and the third semiconductor light emitting element that emits blue light are monolithically integrated, it is possible to mix red, green, and blue light emitted from one chip. The white semiconductor light emitting device can be provided.

Further, by epitaxially growing the p-type SiC clad layer 41 on the n-type SiC single crystal substrate 32, an integrated structure with pn junction separation becomes possible. For example, red light is emitted on the n-type SiC single crystal substrate 32 by changing the composition x of Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7). If the first semiconductor light emitting device that emits light, the second semiconductor light emitting device that emits green light, and the third semiconductor light emitting device that emits blue light are monolithically integrated by separating pn junctions, one chip The red, green, and blue light emitted from the light can be mixed, and a one-chip white semiconductor light emitting device can be provided. In order to locally change the composition x of Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7), an epitaxial growth method or a A method of growing using a focused ion beam while locally controlling the composition of Cd may be employed.

Furthermore, the light emission intensity of each of the first semiconductor light emitting element that emits red light, the second semiconductor light emitting element that emits green light, and the third semiconductor light emitting element that emits blue light can be adjusted. For example, it is possible to provide a semiconductor light emitting device that emits light by mixing light of an arbitrary wavelength in a full color spectral band at an arbitrary ratio with one chip. In this case, the _first to third semiconductor light emitting elements made of the same material Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7) are monolithically integrated. Therefore, the difference in operating voltage between the first to third semiconductor light emitting elements covering the full color can be reduced as compared with the case where the full color is covered by combining the semiconductor light emitting elements of completely different materials. The design of the power supply circuit of the first to third semiconductor light emitting elements is facilitated. In addition, since the power supply circuits of the first to third semiconductor light emitting elements are reduced in size, the power supply circuits can be easily integrated monolithically.

<Method for Manufacturing Semiconductor Light-Emitting Element According to Fourth Embodiment>
Next, with reference to FIG. 13, a method for manufacturing a semiconductor light emitting element according to the fourth embodiment of the present invention will be described. The semiconductor light emitting device manufacturing method described below is an example, and it is needless to say that the semiconductor light emitting device can be realized by various other manufacturing methods including this modification. For example, in the following description, the process of growing the p-type SiC clad layer 41 on the n-type SiC single crystal substrate 32 is described using a low pressure CVD (LPCVD) apparatus. If the type SiC cladding layer 41 is grown on the n-type SiC single crystal substrate 32, it can be grown at a lower temperature.

(A) First, the n-type SiC single crystal substrate 32 is washed with an organic solvent such as acetone or methanol. Then, after ultrasonically cleaning with ultrapure water, it is blown with high purity nitrogen or the like and dried. Thereafter, the surface of n-type SiC single crystal substrate 32 is etched with molten NaOH (500 degrees), and washed (rinsed) with pure water. Then, etching with 5% to 100% (preferably 5 to 20%) diluted hydrofluoric acid (etching the oxide layer), cleaning with pure water, and further SiC coated carbon susceptor provided in a SiC LPCVD apparatus. To be installed. After setting the n-type SiC single crystal substrate 32 on the carbon susceptor, the inside of the chamber of the LPCVD apparatus is evacuated to about 10 ⁻² Pa to 10 ⁻⁸ Pa and heated to a substrate temperature of 1400 ° C. When the temperature of the carbon susceptor reaches about 1400 ° C., propane (C ₃ H ₈ ) gas is introduced into the chamber of the LPCVD apparatus via the mass flow controller. Further, after reaching 1400 ° C., 1 minute later, the carbon susceptor is heated to a growth temperature, for example, 1600 ° C. 3 minutes after reaching the growth temperature, the growth pressure is 20 kPa, the supply flow rate of monosilane (SiH ₄ ) gas is 1.1 × 10 ⁻² Pa · m ³ / s (= 6.67 sccm), C ₃ H ₈ supply flow rate is ^{5.6 × 10 -3 Pa · m 3} /s(=3.33sccm), the supply flow rate of trimethylaluminum dopant material (TMAl) is ^{1.7 × 10 -5 Pa · m 3} / s (= The p-type SiC cladding layer 41 is grown at a supply flow rate of hydrogen of 0.01 sccm,) carrier gas at 6.8 × 10 Pa · m ³ / s (= 40000 sccm).

(B) Next, the n-type SiC single crystal substrate 32 on which the p-type SiC cladding layer 41 is grown is transferred into the stainless steel chamber 66 of the remote plasma excitation MOCVD apparatus shown in FIG. That is, the n-type SiC single crystal substrate 32 is taken out from the LPCVD apparatus, and the n-type SiC single crystal substrate 32 is transported onto the SiC-coated carbon susceptor 72 provided in the stainless steel chamber 66. This conveyance is preferably performed in a vacuum by a load lock method. Then, after setting the n-type SiC single crystal substrate 32 on the carbon susceptor 72, the inside of the stainless steel chamber 66 is evacuated to about 10 ⁻² Pa to 10 ⁻⁸ Pa and heated to a substrate temperature of 600 ° C. Then, hydrogen (H ₂ ) gas is introduced so that the chamber temperature becomes 13 Pa to 1.3 Pa at a substrate temperature of 600 ° C., and hydrogen radicals are removed in a hydrogen atmosphere for at least 45 minutes, preferably about 1 hour. Irradiate and clean the surface of the p-type SiC cladding layer 41 with hydrogen radicals.

  (C) Thereafter, the substrate temperature is set to an optimum substrate temperature of about 300 ° C. to 600 ° C. (may be 300 ° C. or less depending on the case), DEZn gas is introduced into the surface of the p-type SiC cladding layer 41, and Zn raw material is supplied. Then, at least one atomic layer, preferably almost one atomic layer, is grown on the surface of the p-type SiC cladding layer 41 by irradiation with hydrogen radicals.

(D) Thereafter, irradiation of hydrogen radicals is stopped, Zn raw material (DEZn) and Cd raw material (DMCd) are introduced into the surface of the p-type SiC cladding layer 41, irradiation with oxygen radicals is performed, and the p-type SiC cladding layer 41 On the surface, Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7) to be the light emitting layer 12 is grown. The Cd composition x can be controlled by changing the flow ratio of the Zn raw material (DEZn) and the Cd raw material (DMCd). Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, in particular 0.07 <x ≦ 0.7) growth of the Zn source (DEZn) and Cd source (DMCd) is the substrate surface (chemical reaction region) ) Are combined in the same line and combined with oxygen radicals in a hydrogen gas atmosphere to cause a chemical reaction. At this time, it is preferable to set it as 10 cc / min or more of hydrogen gas with respect to the oxygen flow rate for oxygen radicals of 5 cc / min. The electrical conductivity (resistivity) of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) film is the same as that of the semiconductor light emitting device according to the first embodiment. As described in the manufacturing method, it can be controlled to a desired value by controlling the substrate temperature or the group VI material / group II material ratio. In the method for manufacturing a semiconductor light emitting device according to the fourth embodiment, for example, the growth is performed at a substrate temperature of 400 ° C.

(E) Further, after growing Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7), the Zn raw material (DEZn), Mg at a substrate temperature of 400 ° C. A raw material (EtCp ₂ Mg) is introduced into the surface of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) film and irradiated with oxygen radicals to form the n-type cladding layer 13 on the surface of the light emitting layer 12. _{mg z Zn 1-z O (} 0 ≦ z ≦ 1) is grown. The composition z of the Mg _z Zn _1-z O (0 ≦ z ≦ 1) thin film can be controlled by changing the flow ratio of the Zn source (DEZn) and the Mg source (EtCp ₂ Mg). Similar to the growth of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) film, the growth rate of the Mg _z Zn _1-z O (0 ≦ z ≦ 1) film is 5 cc / min for the oxygen radical oxygen flow rate. The hydrogen gas is preferably 10 cc / min or more. Further, after growing Mg _z Zn _1-z O (0 ≦ z ≦ 1) to be the n-type cladding layer 13, the substrate temperature is raised to 600 ° C., and Zn source (DEZn), Mg source (EtCp ₂ Mg) Is introduced into the surface of the n-type cladding layer 13 and irradiated with oxygen radicals, and the surface of the n-type cladding layer 13 is coated with Mg _z Zn _1-z O serving as an ohmic contact layer 14 as shown in FIG. Growing (0 ≦ z ≦ 1). Similar to the growth of the Zn _1-x Cd _x O (0 ≦ x ≦ 0.7) film, the electrical conductivity (resistivity) is also increased in the growth of the Mg _z Zn _1-z O (0 ≦ z ≦ 1) film. Since it can be controlled by the substrate temperature, by increasing the substrate temperature to 600 ° C., an n-type Mg _z Zn _1-z O (0) having an impurity density of about 2 × 10 ¹⁸ cm ^{−3 to} 5 × 10 ¹⁹ cm ^−3. ≦ z ≦ 1) A film can be grown. Furthermore, the resistivity may be decreased by setting the VI group / II group ratio to 60 or less in terms of moles.

(F) Next, after applying a photoresist to the entire surface of the ohmic contact layer 14, the photoresist is patterned by a normal photolithography technique to form a lift-off mask. Through this lift-off mask, a sulfate-resistant metal film 19 such as Au is deposited by a vacuum vapor deposition method, a sputtering method or the like, and then the lift-off mask is removed, whereby the U-groove etching mask is patterned. Then, if the ohmic contact layer 14, the n-type cladding layer 13 and the light emitting layer 12 are selectively etched with a dilute sulfuric acid / dilute nitric acid (HNO ₃ ) solution using the U-groove etching mask 19, FIG. As shown in FIG. 4, a U-groove 51 that reaches the surface of the p-type cladding layer 41 through the ohmic contact layer 14, the n-type cladding layer 13, and the light emitting layer 12 can be formed.

(G) Thereafter, polishing is performed until the surface of the ohmic contact layer 14 is exposed, and the U-groove etching mask 19 is removed. Thereafter, as shown in FIG. 13C, an anode made of a metal material such as Ni, Al / Ni, Al / Ti, Al / TaSi ₂ , or TiC / Al is used at the bottom of the U groove 51 by using a lift-off method. (Anode electrode) 18 is patterned. Further, a metal film such as In, In / Au, Au / Ge, etc. is patterned using a lift-off method to form a cathode (cathode electrode) 15 as shown in FIG. Thereafter, heat treatment (sintering) is performed to reduce the contact resistance of the cathode 15 and the anode 18. Finally, the semiconductor shown in FIG. 12 is obtained by cleaving into a rectangular shape of a predetermined size such as 300 μm × 300 μm to 1.5 mm × 1.5 mm using a portion of the U groove 51 or cutting with a diamond blade or the like. A light emitting element is completed.

According to the method for manufacturing a semiconductor light emitting device according to the fourth embodiment of the present invention, a wide spectrum of red light (1.8 eV) to purple (3.1 eV) and further ultraviolet light (3.3 eV) at room temperature. A semiconductor light emitting device that can emit light in a range, is thermally stable, and has little risk of resource depletion can be easily manufactured. In particular, the remote plasma-excited MOCVD method is used to introduce radicals into the reaction process to promote surface reaction and to perform crystal growth with a high degree of non-equilibrium at low temperatures. By changing the flow ratio of Cd, Cd exceeding the thermodynamic solid solution limit can be introduced into the Zn _1-x Cd _x O thin film to be the light emitting layer 12, and the composition of Cd can be arbitrarily controlled. In this way, by controlling the composition x of Zn _1-x Cd _x O (0 ≦ x ≦ 0.7), a plurality (a group) of semiconductor light-emitting elements that enable full-color light emission can be manufactured. As a result, a plurality of (a group of) semiconductor light emitting elements made of the same material with a full color spectral band of Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7). The difference in the operating voltage of each of a plurality of (a group of) semiconductor light emitting elements covering the full color can be reduced as compared with the case where the semiconductor light emitting elements of completely different materials are combined to cover the full color, The circuit configuration is simplified.

<Modification of Fourth Embodiment>
As explained at the beginning of the fourth embodiment, in the semiconductor light emitting device according to the fourth embodiment of the present invention, the p-type cladding layer is not limited to the p-type SiC single crystal thin film. A p-type ZnO single crystal thin film or a p-type GaN single crystal thin film may be used. The substrate is not limited to an n-type SiC single crystal substrate, and may be an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate, or an insulating sapphire (Al ₂ O ₃ ) substrate.

As shown in FIG. 14, the semiconductor light emitting device according to the first modification of the fourth embodiment of the present invention includes a substrate 33 made of n-type ZnO single crystal having a plane orientation (0001) plane, and a substrate 33. A p-type cladding layer 42 made of a p-type ZnO single crystal thin film and an n-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7), The light emitting layer 12 which makes a heterojunction with the clad layer 42 is provided.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 12. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. Furthermore, other features such as a double hetero structure and the effects of the structure of FIG. 14 are the same as described with reference to FIG. In order to epitaxially grow the p-type cladding layer 42 made of a p-type ZnO single crystal thin film on the n-type ZnO single crystal substrate 33, a Zn material (DEZn) is introduced into the surface of the n-type ZnO single crystal substrate 33. A remote plasma excitation MOCVD method of irradiating oxygen radicals may be used. Further, on the surface of the p-type cladding layer 42, a light emitting layer 12 made of n _- type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7) in order, n-type Mg _{z Zn 1-z O (0} ≦ z ≦ 1) n -type cladding layer 13 made of, n-type _{Mg z Zn 1-z O (} 0 ≦ z ≦ 1) for continuously depositing the ohmic contact layer 14 made of In addition, a remote plasma excitation MOCVD method may be used.

A semiconductor light emitting device according to a second modification of the fourth embodiment of the present invention includes, as shown in FIG. 15, a substrate 34 made of an n-type GaN single crystal having a plane orientation (0001) plane, and a substrate 34. a p-type cladding layer 43 composed of arranged p-type GaN single crystal thin film, an n-type _{Zn 1-x Cd x O (} 0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7), The light emitting layer 12 which makes a hetero junction with the clad layer 43 is provided.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 12. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. Furthermore, other features such as a double hetero structure and the effects of the structure of FIG. 15 are the same as described with reference to FIG.

In order to epitaxially grow the p-type cladding layer 43 made of a p-type GaN single crystal thin film on the n-type GaN single crystal substrate 34, trimethyl gallium (TMG), which is an MO gas, is used as a group III gas in a normal MOCVD method. Then, ammonia (NH ₃ ) gas may be used as the group V gas. Alternatively, a p-type cladding layer 43 made of a p-type GaN single crystal thin film is epitaxially grown on the n-type GaN single crystal substrate 34 by using a Ga—HCl—NH ₃ -based chloride transport vapor deposition method. May be.

As shown in FIG. 16, the semiconductor light emitting device according to the third modification of the fourth embodiment of the present invention has a plane orientation of (0001) plane, (12-20) plane, or (01-12) plane. A substrate 31 made of an insulating sapphire substrate, a p-type cladding layer 41 made of a p-type SiC single crystal thin film disposed on the substrate 31, and an n-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7 , In particular 0.07 <x ≦ 0.7), and includes a light emitting layer 12 that forms a heterojunction with the cladding layer 41.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 12. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, since other features such as a double hetero structure and the effect of the structure of FIG. 16 are the same as described with reference to FIG.

As shown in FIG. 17, the semiconductor light emitting device according to the fourth modification of the fourth embodiment of the present invention has a plane orientation of (0001) plane, (12-20) plane, or (01-12) plane. A substrate 31 made of an insulating sapphire substrate, a p-type cladding layer 42 made of a p-type ZnO single crystal thin film disposed on the substrate 31, and an n-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7 , In particular 0.07 <x ≦ 0.7), and includes a light emitting layer 12 that forms a heterojunction with the cladding layer 42.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 12. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. Furthermore, the other features such as the double hetero structure and the effects of the structure of FIG. 17 are the same as those described with reference to FIG.

As shown in FIG. 18, the semiconductor light emitting device according to the fifth modification of the fourth embodiment of the present invention has a plane orientation of (0001) plane, (12-20) plane, or (01-12) plane. A substrate 31 made of an insulating sapphire substrate, a p-type cladding layer 43 made of a p-type GaN single crystal thin film disposed on the substrate 31, and an n-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7 , Especially 0.07 <x ≦ 0.7), and includes a light emitting layer 12 that forms a heterojunction with the cladding layer 43.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 12. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, since other features such as a double hetero structure and the effect of the structure of FIG. 18 are the same as those described with reference to FIG. 12, the redundant description is omitted.

  The semiconductor light emitting device according to the modification of the fourth embodiment of the present invention is not limited to the combination of the p-type cladding layer and the substrate illustrated in FIGS. 13 to 18, but a p-type SiC cladding. Layer, p-type ZnO clad layer or p-type GaN clad layer may be epitaxially grown on any of an n-type SiC single crystal substrate, an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate or an insulating sapphire substrate. I do not care.

(Fifth embodiment)
As shown in FIG. 19, the semiconductor light emitting device according to the fifth embodiment of the present invention includes a substrate 32 made of a hexagonal single crystal and a hexagonal single crystal having a forbidden band width Eg of 2.8 eV or more. A clad layer 41 made of a thin film and a wurtzite structure and a ZnO-based compound semiconductor mixed crystal having a forbidden band width Eg = 1.8 eV or more and less than 3.1 eV and heterogeneous with the clad layer 41. And a light emitting layer 21 that forms a junction. FIG. 19 illustrates the case where a p-type SiC single crystal thin film having an impurity density of about 6 × 10 ¹⁷ cm ⁻³ to 1 × 10 ¹⁹ cm ⁻³ is used as the p-type cladding layer 41. Is not limited to a p-type SiC single crystal thin film, but may be a p-type ZnO single crystal thin film or a p-type GaN single crystal thin film as shown in FIG. 20 and FIG. This is the same as the semiconductor light emitting device according to the above. The substrate 32 is an n-type SiC single crystal substrate such as 2H—SiC, 4H—SiC, 6H—SiC, or 8H—SiC. However, as in the semiconductor light emitting device according to the fourth embodiment, the n type is used. The substrate is not limited to a SiC single crystal substrate, and may be an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate, or an insulating sapphire (Al ₂ O ₃ ) substrate.

The ZnO-based compound semiconductor mixed crystal constituting the light emitting layer 21 is an n-type having an impurity density of about 1 × 10 ¹⁶ cm ⁻³ to 1 × 10 ¹⁸ cm ⁻³ as in the semiconductor light emitting device according to the second embodiment. Zn _1-x Cu _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7).

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 21. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, the semiconductor device according to the second embodiment is characterized in that a double heterostructure is further provided, and that the ohmic contact layer 14 is provided with a cathode (cathode electrode) 15 made of a metal thin film such as In. The same as the light emitting element.

However, the anode (anode electrode) 18 reaches the surface of the p-type cladding layer 41 through the ohmic contact layer 14, the n-type cladding layer 13, and the light emitting layer 21 instead of the back surface of the n-type SiC single crystal substrate 32. The semiconductor light emitting element according to the second embodiment is different from the semiconductor light emitting element according to the second embodiment in that the groove is provided at the bottom of the groove (step). However, the material of the anode (anode electrode) 18 is the same metal material as Ni, Al / Ni, Al / Ti, Al / TaSi ₂ , TiC / Al, etc., as in the semiconductor light emitting device according to the second embodiment. Can be adopted.

  In the semiconductor light emitting device according to the fifth embodiment shown in FIG. 19, the thickness of the substrate 32 can be 0.1 mm to 1 mm, preferably about 0.2 mm to 0.8 mm. The thickness of a commercially available substrate (for example, about 0.3 mm to 0.6 mm) may be applied as it is. The thickness of the p-type cladding layer 41 may be selected from about 20 nm to 800 nm, preferably about 200 nm to 500 nm. The thickness of the light emitting layer 21 may be selected from about 5 nm to 400 nm, preferably about 50 nm to 200 nm. The thickness of the n-type cladding layer 13 may be selected from about 20 nm to 800 nm, preferably about 200 nm to 500 nm, and the thickness of the ohmic contact layer 14 may be selected from about 10 nm to 100 nm, preferably about 10 nm to 30 nm. Furthermore, the thickness of the cathode 15 and the anode 18 may be selected from about 100 nm to 2 μm, preferably about 0.5 μm to 2 μm.

  The energy band structure of the main part of the semiconductor light emitting device according to the fifth embodiment of the present invention is the same as the energy band structure of the main part of the semiconductor light emitting device according to the first embodiment shown in FIG. Therefore, a duplicate description is omitted.

According to the semiconductor light emitting device of the fifth embodiment of the present invention, light emission in a wide spectral range of red light (1.8 eV) to violet (3.1 eV) and further ultraviolet light (3.3 eV) at room temperature. Therefore, it is possible to provide a semiconductor light emitting element that is thermally stable and has little risk of resource depletion. In particular, by varying the Zn _1-x Cu _x composition x of O (0 ≦ x ≦ 1) , since the enabling full-color emission, the spectrum band of the _{full-color, Zn 1-x Cu x O} (0 ≦ x Since it is possible to provide a plurality (a group) of semiconductor light-emitting elements made of the same material of ≦ 0.7, particularly 0.07 <x ≦ 0.7, each of the plurality of (a group of) semiconductor light-emitting elements covering a full color The difference in operating voltage can be made smaller than when a full color is covered by combining semiconductor light emitting elements of completely different materials. In particular, since the anode 18 is formed on the surface of the p-type cladding layer 41, the n-type SiC single crystal substrate 32 may be a substrate with a high specific resistance, and the degree of freedom of substrate selection increases.

Further, by epitaxially growing the p-type SiC clad layer 41 on the n-type SiC single crystal substrate 32, an integrated structure with pn junction separation becomes possible. For example, the composition x of Zn _1-x Cu _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) is changed on the n-type SiC single crystal substrate 32 to change the red color If the first semiconductor light emitting element that emits light, the second semiconductor light emitting element that emits green light, and the third semiconductor light emitting element that emits blue light are monolithically integrated by separating the pn junction, 1 Red, green, and blue light emitted from the chip can be mixed, and a one-chip white semiconductor light-emitting element can be provided. _{Zn 1-x Cu x O (} 0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) to locally vary the composition x, Ya selectively epitaxial growth method regions of different compositions A method of growing using a focused ion beam while locally controlling the composition of Cu may be adopted.

Furthermore, the light emission intensity of each of the first semiconductor light emitting element that emits red light, the second semiconductor light emitting element that emits green light, and the third semiconductor light emitting element that emits blue light can be adjusted. For example, it is possible to provide a semiconductor light emitting device that emits light by mixing light of an arbitrary wavelength in a full color spectral band at an arbitrary ratio with one chip. In this _{case, Zn 1-x Cu x O} (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) and pn junction isolation the first to third semiconductor light emitting element made of the same material as Since it is monolithically integrated, the difference in operating voltage between the first to third semiconductor light emitting elements covering the full color is smaller than when the semiconductor light emitting elements of completely different materials are combined to cover the full color. Therefore, the design of the power supply circuit of the first to third semiconductor light emitting elements is facilitated. In addition, since the power supply circuits of the first to third semiconductor light emitting elements are reduced in size, the power supply circuits can be easily integrated monolithically.

As described in the method for manufacturing a semiconductor light emitting device according to the second embodiment of the present invention, the method for manufacturing a semiconductor light emitting device according to the fifth embodiment of the present invention is performed on the p-type SiC single crystal substrate 11. Except for the point that the Zn _1-x Cu _x O thin film is epitaxially grown, it can be manufactured basically by the same method as that of the semiconductor light emitting device according to the first embodiment. In the epitaxial growth of a Zn _1-x Cu _x O thin film, DEZn gas is introduced into the surface of the p-type SiC single crystal substrate 11, a Zn raw material is supplied, and an atomic layer of Zn is formed on the p-type SiC single crystal substrate 11 by hydrogen radical irradiation. After at least one atomic layer, preferably approximately one atomic layer, is grown on the surface, a Zn raw material (DEZn), a Cu raw material (Cu (thd) 2, etc.) is introduced into the surface of the p-type SiC single crystal substrate 11 to generate oxygen radicals. May be performed. The Cu composition x can be controlled by changing the flow rate ratio between the Zn raw material (DEZn) and the Cu raw material (Cu (thd) 2 etc.).

<Modification of Fifth Embodiment>
As explained at the beginning of the fifth embodiment, in the semiconductor light emitting device according to the fifth embodiment of the present invention, the p-type cladding layer is not limited to the p-type SiC single crystal thin film. A p-type ZnO single crystal thin film or a p-type GaN single crystal thin film may be used. The substrate is not limited to an n-type SiC single crystal substrate, and may be an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate, or an insulating sapphire (Al ₂ O ₃ ) substrate.

As shown in FIG. 20, a semiconductor light emitting device according to a first modification of the fifth embodiment of the present invention includes a substrate 33 made of n-type ZnO single crystal, and a p-type ZnO single unit disposed on the substrate 33. a p-type clad layer 42 made of crystalline thin film, n-type _{Zn 1-x Cu x O (} 0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) consists, the cladding layer 42 and heterojunction And a light emitting layer 21 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 21. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. Furthermore, the other features such as the double hetero structure and the effect of the structure of FIG. 20 are the same as those described with reference to FIG. In order to epitaxially grow the p-type cladding layer 42 made of a p-type ZnO single crystal thin film on the n-type ZnO single crystal substrate 33, a Zn material (DEZn) is introduced into the surface of the n-type ZnO single crystal substrate 33. A remote plasma excitation MOCVD method of irradiating oxygen radicals may be used. Further, on the surface of the p-type cladding layer 42, a light emitting layer 21 made of n _- type Zn _1-x Cu _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7) in order, n-type Mg _{z Zn 1-z O (0} ≦ z ≦ 1) n -type cladding layer 13 made of, n-type _{Mg z Zn 1-z O (} 0 ≦ z ≦ 1) for continuously depositing the ohmic contact layer 14 made of In addition, a remote plasma excitation MOCVD method may be used.

As shown in FIG. 21, a semiconductor light emitting device according to a second modification of the fifth embodiment of the present invention includes a substrate 34 made of an n-type GaN single crystal, and a p-type GaN single layer disposed on the substrate 34. A p-type cladding layer 43 made of a crystalline thin film and an n-type Zn _1-x Cu _x O (0 ≦ x ≦ 0.7, in particular 0.07 <x ≦ 0.7), and a heterojunction with the cladding layer 43 And a light emitting layer 21 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 21. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. Furthermore, other features such as a double hetero structure and the effects of the structure of FIG. 21 are the same as those described with reference to FIG. As described in the description of the semiconductor light emitting device according to the second modification of the fourth embodiment, the p-type cladding layer 43 made of a p-type GaN single crystal thin film is formed on the n-type GaN single crystal substrate 34. In order to perform epitaxial growth, in a normal MOCVD method, trimethylgallium (TMG), which is an MO gas, may be used as a group III gas, and ammonia (NH ₃ ) gas may be used as a group V gas. Alternatively, a p-type cladding layer 43 made of a p-type GaN single crystal thin film is epitaxially grown on the n-type GaN single crystal substrate 34 by using a Ga—HCl—NH ₃ -based chloride transport vapor deposition method. May be.

As shown in FIG. 22, a semiconductor light emitting device according to a third modification of the fifth embodiment of the present invention includes a substrate 31 made of an insulating sapphire substrate, and a p-type SiC unit disposed on the substrate 31. A p-type cladding layer 41 made of a crystal thin film and n-type Zn _1-x Cu _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) And a light emitting layer 21 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 21. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. Furthermore, the other features such as the double hetero structure and the effects of the structure of FIG. 22 are the same as described with reference to FIG.

As shown in FIG. 23, a semiconductor light emitting device according to a fourth modification of the fifth embodiment of the present invention includes a substrate 31 made of an insulating sapphire substrate, and a p-type ZnO single unit disposed on the substrate 31. a p-type cladding layer 42 made of crystalline thin film, n-type _{Zn 1-x Cu x O (} 0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) consists, a clad layer 42 and heterojunction And a light emitting layer 21 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 21. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, since other features such as a double hetero structure and the effect of the structure of FIG. 23 are the same as those described with reference to FIG.

As shown in FIG. 24, a semiconductor light emitting device according to a fifth modification of the fifth embodiment of the present invention includes a substrate 31 made of an insulating sapphire substrate, and a p-type GaN single unit disposed on the substrate 31. a p-type cladding layer 43 made of crystalline thin film, n-type _{Zn 1-x Cu x O (} 0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) consists, a clad layer 43 and heterojunction And a light emitting layer 21 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 21. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. Furthermore, the other features such as the double hetero structure and the effects of the structure of FIG. 24 are the same as described with reference to FIG.

  The semiconductor light emitting device according to the modification of the fifth embodiment of the present invention is not limited to the combination of the p-type cladding layer and the substrate illustrated in FIGS. Layer, p-type ZnO clad layer or p-type GaN clad layer may be epitaxially grown on any of an n-type SiC single crystal substrate, an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate or an insulating sapphire substrate. I do not care.

(Sixth embodiment)
As shown in FIG. 25, the semiconductor light emitting device according to the sixth embodiment of the present invention includes a substrate 32 made of a hexagonal single crystal and a hexagonal single crystal having a forbidden band width Eg of 2.8 eV or more. A clad layer 41 made of a thin film and disposed on the substrate 32, a wurtzite structure, a ZnO-based compound semiconductor mixed crystal having a forbidden band width Eg = 1.8 eV or more and less than 3.1 eV, And a light emitting layer 22 forming a junction. 25 exemplifies a case where a p-type SiC single crystal thin film having an impurity density of about 6 × 10 ¹⁷ cm ⁻³ to 1 × 10 ¹⁹ cm ⁻³ is used as the p-type cladding layer 41. Is not limited to a p-type SiC single crystal thin film, but may be a p-type ZnO single crystal thin film or a p-type GaN single crystal thin film as shown in FIGS. This is the same as the semiconductor light emitting device according to the embodiment. The substrate 32 is an n-type SiC single crystal substrate such as 2H—SiC, 4H—SiC, 6H—SiC, or 8H—SiC, but is similar to the semiconductor light emitting device according to the fourth and fifth embodiments. The n-type SiC single crystal substrate is not limited to an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate, or an insulating sapphire (Al ₂ O ₃ ) substrate.

The ZnO-based compound semiconductor mixed crystal constituting the light emitting layer 22 is a p-type having an impurity density of about 1 × 10 ¹⁶ cm ⁻³ to 1 × 10 ¹⁸ cm ⁻³ , similar to the semiconductor light emitting device according to the third embodiment. _{Zn 1-x Cd x O (} 0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) it is.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 22. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, the semiconductor device according to the third embodiment is configured such that a double hetero structure is provided, and that the ohmic contact layer 14 is provided with a cathode (cathode electrode) 15 made of a metal thin film such as In. The same as the light emitting element.

However, the anode (anode electrode) 18 reaches the surface of the p-type cladding layer 41 through the ohmic contact layer 14, the n-type cladding layer 13, and the light emitting layer 22, not the back surface of the n-type SiC single crystal substrate 32. It differs from the semiconductor light emitting device according to the third embodiment in that it is provided at the bottom of the groove (step). However, the material of the anode (anode electrode) 18 is a metal material such as Ni, Al / Ni, Al / Ti, Al / TaSi ₂ , TiC / Al, etc., similar to the semiconductor light emitting device according to the third embodiment. Can be adopted.

  In the semiconductor light emitting device according to the sixth embodiment shown in FIG. 25, the thickness of the substrate 32 can be 0.1 mm to 1 mm, preferably about 0.2 mm to 0.8 mm. The thickness of a commercially available substrate (for example, about 0.3 mm to 0.6 mm) may be applied as it is. The thickness of the p-type cladding layer 41 may be selected from about 20 nm to 800 nm, preferably about 200 nm to 500 nm, and the thickness of the light emitting layer 22 may be selected from about 5 nm to 400 nm, preferably about 50 nm to 200 nm. The thickness of the n-type cladding layer 13 may be selected from about 20 nm to 800 nm, preferably about 200 nm to 500 nm, and the thickness of the ohmic contact layer 14 may be selected from about 10 nm to 100 nm, preferably about 10 nm to 30 nm. Furthermore, the thickness of the cathode 15 and the anode 18 may be selected from about 100 nm to 2 μm, preferably about 0.5 μm to 2 μm.

  The energy band structure of the main part of the semiconductor light emitting device according to the sixth embodiment of the present invention is the same as the energy band structure of the main part of the semiconductor light emitting device according to the third embodiment shown in FIG. Therefore, a duplicate description is omitted.

According to the semiconductor light emitting device of the sixth embodiment of the present invention, light emission in a wide spectral range of red light (1.8 eV) to purple (3.1 eV) and further ultraviolet light (3.3 eV) at room temperature. Therefore, it is possible to provide a semiconductor light emitting element that is thermally stable and has little risk of resource depletion. In particular, Zn _1-x Cd _x by changing the composition x of O (0 ≦ x ≦ 0.7) , since the enabling full-color emission, the spectrum band of the _{full-color, Zn 1-x Cd x O} (0 Since it is possible to provide a plurality (a group) of semiconductor light-emitting elements made of the same material such that ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7, a plurality of (a group of) semiconductor light-emitting elements covering a full color The difference between the operating voltages can be reduced as compared with a case where a full color is covered by combining semiconductor light emitting elements of completely different materials. In particular, since the anode 18 is formed on the surface of the p-type cladding layer 41, the n-type SiC single crystal substrate 32 may be a substrate with a high specific resistance, and the degree of freedom of substrate selection increases.

Further, by epitaxially growing the p-type SiC clad layer 41 on the n-type SiC single crystal substrate 32, an integrated structure with pn junction separation becomes possible. For example, the composition x of Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) is changed on the n-type SiC single crystal substrate 32 to change the red color If the first semiconductor light-emitting element that emits light, the second semiconductor light-emitting element that emits green light, and the third semiconductor light-emitting element that emits blue light are monolithically integrated by separating the pn junction, 1 Red, green and blue light emitted from the chip can be mixed, and a one-chip white semiconductor light-emitting element can be provided. Furthermore, the light emission intensity of each of the first semiconductor light emitting element that emits red light, the second semiconductor light emitting element that emits green light, and the third semiconductor light emitting element that emits blue light can be adjusted. For example, it is possible to provide a semiconductor light emitting device that emits light by mixing light of an arbitrary wavelength in a full color spectral band at an arbitrary ratio with one chip. In this _{case, Zn 1-x Cu x O} (0 ≦ x ≦ 0.7, especially 0.07 <x ≦ 0.7) and pn junction isolation the first to third semiconductor light emitting element made of the same material as Since it is monolithically integrated, the difference in operating voltage between the first to third semiconductor light emitting elements covering the full color is smaller than when the semiconductor light emitting elements of completely different materials are combined to cover the full color. Therefore, the design of the power supply circuit of the first to third semiconductor light emitting elements is facilitated. In addition, since the power supply circuits of the first to third semiconductor light emitting elements are reduced in size, the power supply circuits can be easily integrated monolithically.

As described in the method for manufacturing a semiconductor light emitting device according to the third embodiment of the present invention, the method for manufacturing a semiconductor light emitting device according to the sixth embodiment of the present invention includes p-type Zn _1-x Cd _x. Except for the point that the light emitting layer 22 made of an O thin film is epitaxially grown on the surface of the p-type cladding layer 41, this is basically the same as the method for manufacturing the semiconductor light emitting device according to the fifth embodiment. For epitaxial growth of the p _- type Zn _1-x Cd _x O thin film, ammonia (NH ₃ ), phosphine (PH ₃ ), arsine (AsH ₃ ), or the like is used as a p-type doping gas. That is, Zn raw material (DEZn) and Cd raw material (DMCd) are introduced into the surface of the p-type cladding layer 41 and irradiated with oxygen radicals to form Zn _1-x Cd _x O (0 ≦ x ≦ 0) that becomes the light emitting layer 22. .7) may be grown by adding a p-type doping gas.

<Modification of Sixth Embodiment>
As described at the beginning of the sixth embodiment, in the semiconductor light emitting device according to the sixth embodiment of the present invention, the p-type cladding layer is not limited to the p-type SiC single crystal thin film. A p-type ZnO single crystal thin film or a p-type GaN single crystal thin film may be used. The substrate is not limited to an n-type SiC single crystal substrate, and may be an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate, or an insulating sapphire (Al ₂ O ₃ ) substrate.

As shown in FIG. 26, a semiconductor light emitting device according to a first modification of the sixth embodiment of the present invention includes a substrate 33 made of n-type ZnO single crystal, and a p-type ZnO single unit disposed on the substrate 33. A p-type cladding layer 42 made of a crystalline thin film and p-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7), and the heterojunction with the cladding layer 42 And a light emitting layer 22 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 22. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, the other features such as the double hetero structure and the effect of the structure of FIG. 26 are the same as those described with reference to FIG. In order to epitaxially grow the p-type cladding layer 42 made of a p-type ZnO single crystal thin film on the n-type ZnO single crystal substrate 33, a Zn material (DEZn) is introduced into the surface of the n-type ZnO single crystal substrate 33. A remote plasma excitation MOCVD method of irradiating oxygen radicals may be used. Further, on the surface of the p-type cladding layer 42, a light emitting layer 22 made of p-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7) in order, n-type Mg _{z Zn 1-z O (0} ≦ z ≦ 1) n -type cladding layer 13 made of, n-type _{Mg z Zn 1-z O (} 0 ≦ z ≦ 1) for continuously depositing the ohmic contact layer 14 made of In addition, a remote plasma excitation MOCVD method may be used.

As shown in FIG. 27, a semiconductor light emitting device according to a second modification of the sixth embodiment of the present invention includes a substrate 34 made of an n-type GaN single crystal, and a p-type GaN single layer arranged on the substrate 34. A p-type cladding layer 43 made of a crystal thin film and p-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7), and a heterojunction with the cladding layer 43 And a light emitting layer 22 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 22. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, the other features such as the double hetero structure and the effect of the structure of FIG. 27 are the same as described with reference to FIG. As described in the description of the semiconductor light emitting device according to the second modification of the fourth and fifth embodiments, the p-type formed of the p-type GaN single crystal thin film on the n-type GaN single crystal substrate 34. In order to epitaxially grow the clad layer 43, in a normal MOCVD method, trimethylgallium (TMG), which is an MO gas, may be used as a group III gas, and ammonia (NH ₃ ) gas may be used as a group V gas. Alternatively, a p-type cladding layer 43 made of a p-type GaN single crystal thin film is epitaxially grown on the n-type GaN single crystal substrate 34 by using a Ga—HCl—NH ₃ -based chloride transport vapor deposition method. May be.

As shown in FIG. 28, a semiconductor light emitting device according to a third modification of the sixth embodiment of the present invention includes a substrate 31 made of an insulating sapphire substrate, and a p-type SiC unit disposed on the substrate 31. A p-type cladding layer 41 made of a crystalline thin film and p-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7), and a heterojunction with the cladding layer 41 And a light emitting layer 22 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 22. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, the other features such as the double hetero structure and the effect of the structure shown in FIG. 28 are the same as those described with reference to FIG.

As shown in FIG. 29, a semiconductor light emitting device according to a fourth modification of the sixth embodiment of the present invention includes a substrate 31 made of an insulating sapphire substrate, and a p-type ZnO single unit disposed on the substrate 31. A p-type cladding layer 42 made of a crystalline thin film and p-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7), and the heterojunction with the cladding layer 42 And a light emitting layer 22 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 22. the ohmic contact layer 14 made of n impurity concentration ^{1 × 10 17 cm -3 ~5 ×} 10 19 cm -3 of about n-type on the type cladding layer _{13 Mg z Zn 1-z O} (0 ≦ z ≦ 1) Furthermore, the other features such as the double hetero structure and the effects of the structure of FIG. 29 are the same as those described with reference to FIG.

A semiconductor light emitting device according to a fifth modification of the sixth embodiment of the present invention includes, as shown in FIG. 30, a substrate 31 made of an insulating sapphire substrate, and a p-type GaN single unit disposed on the substrate 31. A p-type cladding layer 43 made of a crystal thin film and p-type Zn _1-x Cd _x O (0 ≦ x ≦ 0.7, particularly 0.07 <x ≦ 0.7), and a heterojunction with the cladding layer 43 And a light emitting layer 22 formed.

An n-type cladding layer 13 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 6 × 10 ¹⁷ cm ⁻³ is formed on the light emitting layer 22. An ohmic contact layer 14 made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) having an impurity density of about 1 × 10 ¹⁷ cm ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ on the n-type cladding layer 13 is formed. In addition, since other features such as a double hetero structure and the effect of the structure of FIG. 30 are the same as those described with reference to FIG. 25, redundant description is omitted.

  The semiconductor light emitting device according to the modification of the sixth embodiment of the present invention is not limited to the combination of the p-type cladding layer and the substrate illustrated in FIGS. 25 to 30, but a p-type SiC cladding. Layer, p-type ZnO clad layer or p-type GaN clad layer may be epitaxially grown on any of an n-type SiC single crystal substrate, an n-type ZnO single crystal substrate, an n-type GaN single crystal substrate or an insulating sapphire substrate. I do not care.

(Other embodiments)
As described above, the present invention has been described according to the first to sixth embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the fourth to sixth embodiments of the present invention, on the n-type SiC single crystal substrate 32, the n-type ZnO single crystal substrate 33, the n-type GaN single crystal substrate 34, or the insulating sapphire substrate 31, It has been described that an integrated structure is possible by epitaxially growing the p-type SiC clad layer 41, the p-type ZnO clad layer 42, or the p-type GaN clad layer 43. For example, the first semiconductor light emitting element that emits red light on any of the n-type SiC single crystal substrate 32, the n-type ZnO single crystal substrate 33, the n-type GaN single crystal substrate 34, or the insulating sapphire substrate 31. If the second semiconductor light emitting element emitting green light and the third semiconductor light emitting element emitting blue light are monolithically integrated, red, green and blue light emitted from one chip can be mixed. Thus, it has been explained that a one-chip white semiconductor light emitting device can be provided. However, since epitaxial growth in which the composition of the ZnO-based compound semiconductor mixed crystal is locally changed is required, there is a high technical demand.

  Therefore, as shown in FIG. 31, a first semiconductor light emitting element (first layer LED) 81 that emits red light, a second semiconductor light emitting element (second layer LED) 82 that emits green light, and blue A semiconductor light-emitting element mounting body that emits white light can be provided by integrating in a hybrid with a third semiconductor light-emitting element (third layer LED) 83 that emits light and mixing red, green, and blue. In FIG. 31, the first semiconductor light emitting element (first layer LED) 81 includes a p-type cladding layer 612, a light emitting layer 613, and an n-type cladding layer 614 stacked on a sapphire substrate 611. The sapphire substrate 611 is fixed to the support base 64 with an adhesive 602. The cathode 615 can be formed on almost the entire top surface of the n-type cladding layer 614. The central portion of the cathode 615 may be formed of an electrode layer that is transparent to the light emission of the light emitting layer 613. The frame-like peripheral portion of the cathode 615 is composed of a relatively thick In / Au thin film of about 0.5 μm to 2 μm for bonding. The anode 616 does not need to be particularly transparent, but is composed of an Al / Ni thin film or the like. A TAB lead (beam lead) 617 made of a copper (Cu) foil is connected to the frame-shaped peripheral portion of the cathode 615. Similarly, the anode 616 is connected to a TAB lead (beam lead) 618 made of copper foil.

  The second semiconductor light emitting device (second layer LED) 82 includes a p-type cladding layer 622, a light emitting layer 623, and an n-type cladding layer 624 that are stacked on a sapphire substrate 621. The sapphire substrate 621 is fixed on the first semiconductor light emitting element (first layer LED) 81 by a transparent adhesive 605. The cathode 625 can be formed on substantially the entire top surface of the n-type cladding layer 624. The central portion of the cathode 625 may be formed of an electrode layer that is transparent to the light emission of the light emitting layers 613 and 623. The frame-like peripheral portion of the cathode 625 is composed of a relatively thick In / Au thin film having a thickness of about 0.5 μm to 2 μm for bonding. The anode 626 need not be particularly transparent. A TAB lead (beam lead) 627 made of a copper (Cu) foil is connected to the frame-shaped peripheral portion of the cathode 625. Similarly, a TAB lead (beam lead) 628 made of copper foil is connected to the anode 626 made of an Al / Ni thin film or the like.

  Similarly, the third semiconductor light emitting element (third layer LED) 83 includes a p-type cladding layer 632, a light emitting layer 633, and an n-type cladding layer 634 stacked on a sapphire substrate 631. The sapphire substrate 631 is fixed on the second semiconductor light emitting element (second layer LED) 82 by a transparent adhesive 606. The cathode 635 can be formed on substantially the entire top surface of the n-type cladding layer 634. The central portion of the cathode 635 may be formed of an electrode layer that is transparent to the light emission of the light emitting layers 613, 623, 633. The frame-shaped peripheral portion of the cathode 635 is formed of a relatively thick In / Au thin film of about 0.5 μm to 2 μm for bonding. The anode 636 made of an Al / Ni thin film or the like does not have to be particularly transparent. A TAB lead (beam lead) 637 made of a copper (Cu) foil is connected to the frame-shaped peripheral portion of the cathode 635. Similarly, the anode 636 is connected to a TAB lead (beam lead) 638 made of copper foil.

  The TAB leads (beam leads) 617, 627, and 637 are connected to the terminal 603 by a conductive adhesive or the like. The TAB leads (beam leads) 618, 628, and 638 are connected to the terminal 604 by a conductive adhesive or the like. The first, second, and third semiconductor light emitting elements 81, 82, 83 are molded with a resin sealing body 608.

  As shown in FIG. 31, the first semiconductor light emitting element (first layer LED) 81 that emits red light, the second semiconductor light emitting element (second layer LED) 82 that emits green light, and the blue light emission. The first semiconductor light emitting element (first layer LED) 81 that emits red light and the second semiconductor that emits green light are integrated in a hybrid with a third semiconductor light emitting element (third layer LED) 83 that emits light. By adjusting the light emission intensity of the light emitting element (second layer LED) 82 and the third semiconductor light emitting element (third layer LED) 83 that emits blue light, light of an arbitrary wavelength in the full color spectrum band can be obtained. A semiconductor light emitting element mounting body that emits light can be provided.

  Although the present invention exemplifies the structure of the double heterostructure LED in the first to sixth embodiments, the n-type cladding layer 13 and the ohmic contact layer 14 on the light emitting layers 12, 21, 22 are omitted. A heterostructure LED may be used.

Further, the light emitting layer 12 of the first and fourth embodiments is formed by, for example, using a quantum well (QW) layer composed of three Zn _0.3 Cd _0.7 O layers and a barrier composed of five Zn _0.92 Cd _0.08 O layers. You may comprise by the 3 period multiple quantum well (MQW) structure which laminated | stacked the layer alternately. Similarly, the light emitting layer 21 of the second and fourth embodiments or the light emitting layer 22 of the third and sixth embodiments may have an MQW structure.

  Further, the n-type cladding layer 13 and the n-type ohmic contact layer 14 are selectively etched by reactive ion etching (RIE) to form a groove, and the convex portion surrounded by the groove is left to form a ridge structure. In this way, a semiconductor laser having a ridge structure may be configured. In this case, an insulating film is deposited on the entire surface so as to sandwich a ridge (projection) formed by the n-type cladding layer 13 and the n-type ohmic contact layer 14, and then only the insulating film on the n-type ohmic contact layer 14 is deposited. Is etched until the n-type ohmic contact layer 14 is exposed, and the cathode 15 is formed on the exposed n-type ohmic contact layer 14.

  When configuring a semiconductor laser, a p-type guide layer may be inserted between the p-type cladding layers 11, 41, 42, 43 and the light emitting layers 12, 21, 22, and the light emitting layers 12, 21, 22; An n-type guide layer may be inserted into the n-type cladding layer 13. Furthermore, a structure in which an overflow prevention layer for preventing an overflow of electrons is inserted inside the p-type guide layer may be used.

  Further, the structure of nanodots, nanowires, quantum wires, or the like is mixed with a ZnO-based compound semiconductor mixed with a forbidden band Eg = 1.8 eV or more and less than 3.1 eV of the wurtzite structure described in the first to sixth embodiments. You may make it comprise with a crystal.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is typical sectional drawing for demonstrating schematic structure of the semiconductor light-emitting device concerning the 1st Embodiment of this invention. It is an energy band structure in the principal part of the semiconductor light-emitting device according to the first embodiment of the present invention. It is a photoluminescence (PL) spectrum of each Zn _1-x Cd _x O thin film having a composition x = 0, 0.072, 0.13, 0.309, 0.53, 0.697 at room temperature. It shows the Cd composition x of Zn _1-x Cd _x O at room temperature, the relationship between the band gap determined from the optical吸終end (band gap energy) and the band gap was determined from PL emission energy (band gap energy) It is. It is a diagram showing the relationship between Mg _z Zn _1-z O mixed crystal of Mg composition z forbidden band width (band gap El ghee). the relationship between the band gap to the c-axis direction of the lattice constant, a diagram illustrating each the Mg _z Zn _1-z O mixed crystal and Zn _1-x Cd _x O mixed crystal. It is typical sectional drawing for demonstrating the general | schematic structure of a remote plasma excitation MOCVD apparatus. It is typical process sectional drawing explaining the manufacturing method of the semiconductor light-emitting device concerning the 1st Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device concerning the 2nd Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device concerning the 3rd Embodiment of this invention. It is an energy band structure in the principal part of the semiconductor light-emitting device concerning the 3rd Embodiment of this invention. It is typical sectional drawing for demonstrating schematic structure of the semiconductor light-emitting device based on the 4th Embodiment of this invention. It is typical process sectional drawing explaining the manufacturing method of the semiconductor light-emitting device which concerns on the 4th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (1st modification) of the 4th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (2nd modification) of the 4th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (3rd modification) of the 4th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (4th modification) of the 4th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (5th modification) of the 4th Embodiment of this invention. It is typical sectional drawing for demonstrating schematic structure of the semiconductor light-emitting device concerning the 5th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (1st modification) of the 5th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (2nd modification) of the 5th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (3rd modification) of the 5th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (4th modification) of the 5th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (5th modification) of the 5th Embodiment of this invention. It is typical sectional drawing for demonstrating schematic structure of the semiconductor light-emitting device concerning the 6th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (1st modification) of the 6th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (2nd modification) of the 6th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (3rd modification) of the 6th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (4th modification) of the 6th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device which concerns on the modification (5th modification) of the 6th Embodiment of this invention. It is typical sectional drawing for demonstrating the schematic structure of the semiconductor light-emitting device mounting body which mounts the several semiconductor light-emitting device based on other embodiment of this invention. Is a diagram showing the relationship between luminous energy and Stokes shift of the In _1-x Ga _x N.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 41, 42, 43 ... p-type clad layer 12, 21, 22 ... Light emitting layer 13 ... n-type clad layer 14 ... n-type ohmic contact layer 15 ... Cathode 16 ... Photoresist (lift-off mask)
17 ... Metal film 18 ... Anode 19 ... Metal film (U-groove etching mask)
31, 32, 33, 34 ... single crystal substrate 51 ... U groove 61 ... plasma generator 62 ... light source 63 ... photodetector 64a, 64b, 64c ... quartz window 65 ... gas flow guide tube 66 ... stainless steel chamber 69 ... substrate holder 67 ... Flange 68 ... Cooling water 72 ... Carbon susceptor 73 ... Resistance heater 81 ... First semiconductor light emitting element (first layer LED)
82 ... Second semiconductor light emitting element (second layer LED)
83. Third semiconductor light emitting element (third layer LED)
602: Adhesive 603, 604 ... Terminal 605, 606 ... Transparent adhesive 608 ... Resin sealing body 611, 621, 631 ... Sapphire substrate 612, 622, 632 ... P-type clad layer 613, 623, 633 ... Light emitting layer 614 624, 634 ... type cladding layer 615, 625, 635 ... cathode 616, 626, 636 ... anode

Claims (13)

A clad layer made of hexagonal SiC single crystal;
A semiconductor light emitting device comprising a light emitting layer having a wurtzite structure, a ZnO-based compound semiconductor mixed crystal having a forbidden band width of 1.8 eV or more and less than 3.1 eV at room temperature, and forming a heterojunction with the cladding layer . A substrate made of a hexagonal single crystal;
A p-type cladding layer comprising a hexagonal single crystal thin film having a forbidden band width of 2.8 eV or more at room temperature, and disposed on the substrate;
A semiconductor comprising a wurtzite structure, a ZnO-based compound semiconductor mixed crystal having a forbidden band width of 1.8 eV or more and less than 3.1 eV at room temperature, and a light emitting layer forming a heterojunction with the p-type cladding layer Light emitting element.   The semiconductor light emitting element according to claim 1, wherein the cladding layer is a p-type cladding layer made of a p-type SiC single crystal.   3. The semiconductor light emitting device according to claim 2, wherein the p-type cladding layer is a p-type SiC single crystal thin film, a p-type ZnO single crystal thin film, or a p-type GaN single crystal thin film. 5. The semiconductor light-emitting device according to claim 1, wherein the ZnO-based compound semiconductor mixed crystal is Zn _1-x Cd _x O (0.07 <x ≦ 0.7). 5. The semiconductor light-emitting element according to claim 3, further comprising an n-type cladding layer made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) on the light-emitting layer. 5. The semiconductor light emitting element according to claim 3, wherein the light emitting layer is made of p-type Zn _1-x Cd _x O (0.07 <x ≦ 0.7). The semiconductor light emitting element according to claim 6, further comprising an ohmic contact layer made of n-type Mg _z Zn _1-z O (0 ≦ z ≦ 1) on the n-type cladding layer. A first semiconductor light emitting device having a light emitting layer made of a ZnO-based compound semiconductor mixed crystal having a wurtzite structure and a forbidden band width of 1.8 eV or more and less than 3.1 eV at room temperature;
A second semiconductor having a light-emitting layer having a wurtzite structure and a ZnO-based compound semiconductor mixed crystal having a forbidden band width of 1.8 eV or more and less than 3.1 eV at room temperature and having a light emission wavelength different from that of the first semiconductor light-emitting element. A semiconductor light emitting device mounting body comprising: a light emitting device. introducing a Zn source together with hydrogen radicals onto the surface of the p-type SiC single crystal substrate, and growing an atomic layer of Zn on the surface of the p-type SiC single crystal substrate by at least one atomic layer;
The irradiation of the hydrogen radicals is stopped, Zn source and Cd source together with oxygen radicals are introduced into the surface of the p-type SiC single crystal substrate, and Zn _1-x that becomes a light emitting layer is formed on the surface of the p-type SiC single crystal substrate. And Cd _x O (0.07 <x ≦ 0.7). The semiconductor light emitting device according to claim 10, further comprising: irradiating a surface of the p-type SiC single crystal substrate with hydrogen radicals before the step of growing at least one atomic layer of the Zn atomic layer. Manufacturing method.   12. The method of manufacturing a semiconductor light emitting element according to claim 11, wherein the step of irradiating the hydrogen radical before the step of growing at least one atomic layer of the Zn atomic layer is performed for at least 45 minutes. After growing the Zn _1-x Cd _x O (0.07 <x ≦ 0.7), a Zn raw material and an Mg raw material are introduced into the surface of the p-type SiC single crystal substrate together with oxygen radicals, and on the surface, of the semiconductor light-emitting device according to any one of _{Mg z Zn 1-z O (} 0 ≦ z ≦ 1) according to claim 10 to 12, further comprising a step of growing a serving as the cladding layer Production method.

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