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WO2016093257A1 - Light-emitting element and method for manufacturing same - Google Patents

Light-emitting element and method for manufacturing same

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Publication number
WO2016093257A1
WO2016093257A1 PCT/JP2015/084461 JP2015084461W WO2016093257A1 WO 2016093257 A1 WO2016093257 A1 WO 2016093257A1 JP 2015084461 W JP2015084461 W JP 2015084461W WO 2016093257 A1 WO2016093257 A1 WO 2016093257A1
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photonic
light
structure
band
pb
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PCT/JP2015/084461
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French (fr)
Japanese (ja)
Inventor
行雄 鹿嶋
恵里子 松浦
小久保 光典
田代 貴晴
貴史 大川
秀樹 平山
隆一郎 上村
大和 長田
聡 嶋谷
Original Assignee
丸文株式会社
東芝機械株式会社
国立研究開発法人理化学研究所
株式会社アルバック
東京応化工業株式会社
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L33/00Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
    • H01L33/22Roughened surfaces, e.g. at the interface between epitaxial layers
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L33/00Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26Materials of the light emitting region
    • H01L33/30Materials of the light emitting region containing only elements of group III and group V of the periodic system
    • H01L33/32Materials of the light emitting region containing only elements of group III and group V of the periodic system containing nitrogen
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L33/00Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes

Abstract

A semiconductor light-emitting element with a reflective film disposed on a front surface (side) of a GaN substrate and with a photonic crystal periodic structure disposed on a rear surface (side) of the GaN substrate, the photonic crystal periodic structure being such that the design wavelength λV in vacuum, a period a as a periodic structure parameter, and a radius R satisfy the Bragg condition, wherein, in a range of R/a of 0.18 to 0.40, a TM light photonic band structure has two photonic bandgaps within the fourth photonic band.

Description

Light emitting device and a manufacturing method thereof

The present invention relates to a light emitting device and a manufacturing method thereof.

Light emitting diode (LED) or organic EL sapphire substrate semiconductor light-emitting element typified by an (OLED) is formed a high luminance has been demanded, the surface of micron-sized irregularities as a light source for display and lighting applications (PSS: Patterned Sapphire method for improving the light extraction efficiency using the Substrate) is generally used. LED performance is represented by an external quantum efficiency (EQE), the internal quantum efficiency (IQE), an electron injection efficiency (EIE), the product of the light extraction efficiency (LEE) (IQE × EIE × LEE). GaN substrate LED crystal defects at the interface without lattice strain does not occur, since the heat dissipation in the conductive substrate has advantages such as good values ​​of IQE × EIE are very good. However, the refractive index of GaN is as large as 2.5 at a wavelength of 455 nm, the light extraction efficiency because emitted light greater than 80% in the GaN and the air interface is totally reflected internally lost bad. As a new way to increase the light extraction efficiency, a technique for forming a photonic crystal periodic structure having a period of the order of the wavelength of the light to the light extraction layer is introduced. Photonic crystal periodic structure is formed in the interface of two structures having different refractive indices, it is generally uneven, consisting mainly of the pillar structure or hole structure. Then, in the periodic structure is formed region total reflection is suppressed by the presence of light is inhibited, it is known to contribute to improvement in light extraction efficiency by utilizing this (Patent Document 1 reference).

The light-emitting element described in Patent Document 2, a flip chip structure main light extraction surface is the n-type semiconductor layer, to create a recess having two or more stages of the inclined surface to the back surface to improve light extraction efficiency ing. Further controlling the light distribution so that light in the recess upwardly is efficiently emitted.

Patent No. 5315513 Publication JP 2010-74008 JP

Although been photonic crystals created in the light emitting device described in Patent Document 1 aims the light extraction efficiency, there is no disclosure relating to the control of the light distribution.

Recess having two or more stages of the inclined surfaces created in the light emitting device described in Patent Document 2, it is necessary to precisely control the magnitude of the angle and the recess bottom surface of the inclined surfaces, the manufacturing process is complicated It made there is a problem, such as.

The present invention, light extraction efficiency from the GaN substrate back surface is high, and aims to provide a manufacturing method and excellent light-emitting element light distribution.

According to the present invention, having a reflective film on the surface of the GaN substrate (the side), there in the semiconductor light-emitting device having a photonic crystal periodic structure consisting of two structures having different refractive index to the GaN substrate back surface (side) Te, the photonic crystal periodic structure period a and radius R which is a parameter of the design wavelength lambda V and the periodic structure in the vacuum satisfies the Bragg condition at the ratio R / a 0.18 0.40 when is varied, the two photonic band gap (PBG) is present within a fourth photonic band (4 th PB) in the photonic band (PB) structure of the TM light, the photonic band maximum value of the gap corresponding R / a to provide a light emitting device having a photonic crystal composed of the orders m = 3 ~ 4 on the GaN substrate back surface.

Alternatively, when the longitudinal axis of the photonic band structure (ωa / 2πc) is converted to the wavelength lambda V in vacuum, gamma point is symmetrical point of the second photonic band (2 nd PB), M point, K to provide a light emitting device having a photonic crystal closest to R / a or wavelength lambda V × meet at m and a point in a vacuum in one of the points is in the order m = 3 ~ 4 on the GaN substrate back surface. Or order m = 3 when the vertical axis the wavelength lambda V × 3 in a vacuum of, fourth photonic band (4 th PB) to 4 integer multiples and 5 integral multiples each have a fourth photonic band (4 th PB ) photonic crystal made of R / a of or closest contact with either symmetric point and the point on which a light emitting device having the GaN substrate back surface.

Or when the order m = 4, the wavelength lambda V × 4 in a vacuum on the vertical axis, a fourth photonic band (4 th PB) 5 integral multiple, 6 integral multiple, 7 integer multiplied by the fourth photonic band providing (4 th PB) light-emitting element having any of the most or in contact with the point of symmetry and the point becomes in close to R / a photonic crystal in GaN substrate back side on.

Photonic and a photonic crystal composed of the R / a and 0.5a more depth h selected by the simulated by the FDTD method, the light extraction efficiency and light distribution is finally determined to be optimized to provide a light emitting device having crystal in GaN substrate back surface.

Further, the present invention provides a parameter calculation method of the photonic crystal periodic structure in a semiconductor light emitting device according to the above, the ratio of the radius R of the period a and the structure is a parameter of the periodic structure (R / a) provisionally a first step of determining, calculating the average refractive index nav respective refractive indices n1 and n2, and these from the R / a of the structure, and substituted into equation Bragg condition, the order m = 3 and m = about 4, and a second step of obtaining a period a and radius R, by the R / a and the wavelength λ and the dielectric constant ε1 and a plane wave expansion method using ε2 of the structure obtained from the refractive index n1, n2 a third step of analyzing the photonic band structure of TM light, the wavelength in vacuum vertical axis (ωa / 2πc) of the second photonic band TM light (2ndPB) and fourth photonic band (4thPB) In terms of .lambda.V, a fourth step of obtaining a photonic band structure of .lambda.V and ka / 2 [pi in order m = 1, the order m = 3 and m = 4, the second photonic band TM light and (2ndPB) first determined wavelength .lambda.V × m and closest to R / a or meet at a point in the vacuum at each point of symmetry in the four photonic band (4thPB), a fifth and sixth step of the optimization of the candidate, the R / photonic light distribution property and light extraction efficiency change rate of the crystal, 0.18 ≦ R / a ≦ 0.40 made orders all R / a m = 3 finite-difference time-domain method in the 4 corresponding to a ( calculated by the FDTD method), photonic crystals characterized by having a a seventh step of selecting an arbitrary value of more than 0.5 times the greatest period a in order m = 3 ~ 4 with respect to depth the parameters of the periodic structure It is a calculation method.

Alternatively, the present invention provides a parameter calculation method of the photonic crystal periodic structure in a semiconductor light emitting device according to the above, the ratio of the radius R of the period a and the structure is a parameter of the periodic structure (R / a) provisionally a first step of determining, calculating the average refractive index nav respective refractive indices n1 and n2, and these from the R / a of the structure, and substituted into equation Bragg condition, the order m = 3 and m = about 4, and a second step of obtaining a period a and radius R, by the R / a and the wavelength λ and the dielectric constant ε1 and a plane wave expansion method using ε2 of the structure obtained from the refractive index n1, n2 wave of the third step and, in a vacuum longitudinal axis of the second photonic band TM light (2ndPB) and fourth photonic band (4thPB) a (ωa / 2πc) analyzing the photonic band structure of TM light In terms of long .lambda.V, a fourth step of obtaining a photonic band structure of .lambda.V and ka / 2 [pi in order m = 1, the order m = 3 and m = 4, the second photonic band TM light and (2ndPB) sought closest to R / a or meet at a wavelength .lambda.V × m and the point in the vacuum at each symmetry points in the fourth photonic band (4thPB), a fifth and sixth step of the optimization of the candidate, said R photonic light distribution property and light extraction efficiency change rate of the crystal, 0.18 ≦ R / a ≦ 0.40 becomes all R / a the order m = 3 finite-difference time-domain method in the 4 corresponding to / a calculated in (FDTD method), a seventh step of selecting an arbitrary value of more than 0.5 times the greatest period a in order m = 3 ~ 4 with respect to depth, the light extraction efficiency (LEE) rate of change is from the large R / a and the order m , Select the R / a and order m corresponds to the light distribution of interest, diameter, period, depth is determined, and the third step from the obtained photonic crystal optimization resulting in up to the sixth step candidate is a parameter calculation method of the photonic crystal periodic structure, characterized in that it comprises an eighth step of comparing the R / a and other R / a selecting good orientation parameter of a.

Then, to provide a light emitting device having a photonic crystal was prepared by nanoimprint method for collectively transferring a large area organic resist was spin-coated a pattern onto the substrate GaN substrate back surface.

Specifically, by spin coating and the step of spin-coating a large lower resist etch selectivity to the substrate on the substrate, an upper resist having a fluidity and oxygen resistant function to the lower layer resist, the photonic crystal pattern thereon and transferring and a step which provides oxygen resistance exposing the patterned upper resist in oxygen plasma, and performing a pattern forming a lower resist in an oxygen plasma a patterned upper resist having the oxygen resistance as a mask, to provide a light emitting device having a photonic crystal formed in a two-layer resist process for dry-etching the substrate by ICP plasma the patterned lower resist as a mask to a GaN substrate back surface.

This description includes the disclosure of the priority document of the present application Japanese Patent Application No. 2014-248769.

According to the present invention, the light emitting element, high light extraction efficiency from the GaN substrate back surface can provide excellent light-emitting element light distribution.

Structural cross-sectional view showing a configuration example of a light emitting device according to an embodiment of the present invention and (FIG. 1 (a)), a plan view (Figure 1 (b)). It is a diagram showing a state of the transmitted light with respect to TM light for the purpose of transmitting a parameter optimization of the periodic structure. Is a diagram showing a first Brillouin region, further illustrates gamma, M, K point (point of symmetry). It is a diagram illustrating a non-lattice band structure in a uniform medium obtained in the region surrounded by the points of symmetry. It is a diagram illustrating a photonic band (PB) structure of the photonic crystal TM light. Between 1 st PB-2 nd PB, between 3 rd PB-4 th PB, photonic bandgap between 5 th PB-6 th PB to (PBG) and其s PBG1, PBG2, PBG3, and R / a and PBG is a diagram showing the relationship. The vertical axis (ωa / 2πc) in terms of the wavelength lambda V in vacuum, the photonic band structure of the lambda V and ka / 2 [pi in order m = 1 Bragg condition is satisfied second photonic band (2 nd PB) is a diagram illustrating a. The vertical axis (ωa / 2πc) in terms of the wavelength lambda V in vacuum, the photonic band structure of the lambda V and ka / 2 [pi in order m = 1 Bragg condition is satisfied fourth photonic band (4 th PB) is a diagram illustrating a. Is a diagram showing the R / a, which is determined by the order m = 3, Step 4 of R / a = 0.37 (order m = 1) of the second photonic band (2 nd PB) occurs a standing wave ing. Is a diagram showing the R / a, which is determined by the order m = 3, is a diagram showing a condition where fourth photonic band R / a (4 th PB) results in a standing wave. The vertical axis of the Bragg condition is satisfied second photonic band (2 nd PB) to (ωa / 2πc) an integral multiple of the orders in terms of the wavelength lambda V in vacuum (m = 3), the vertical axis: 3 [lambda] V horizontal axis: a view showing a photonic band structure of the ka / 2 [pi. And 4 integral multiple in terms vertical axis (ωa / 2πc) the wavelength lambda V in vacuum Bragg condition is satisfied fourth photonic band (4 th PB), vertical axis: 3 [lambda] V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. And 5 integral multiples in terms of wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied fourth photonic band (4 th PB), vertical axis: 3 [lambda] V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. The vertical axis of the Bragg condition is satisfied second photonic band (2 nd PB) to (ωa / 2πc) an integral multiple of the orders in terms of the wavelength lambda V in vacuum (m = 4), the vertical axis: 4.lamda V horizontal axis: a view showing a photonic band structure of the ka / 2 [pi. And 5 integral multiples in terms of wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied fourth photonic band (4 th PB), vertical axis: 4.lamda V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. And 6 integral multiple in terms of the wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied fourth photonic band (4 th PB), vertical axis: 4.lamda V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. And 7 integral multiple in terms of the wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied fourth photonic band (4 th PB), vertical axis: 4.lamda V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. Finite Difference Time Domain method is a diagram showing a calculation model calculated by (FDTD method) (pillar). The radiation pattern calculation parameters 其 s 0 ° ≦ θ ≦ 180 °, a diagram showing how to calculate at 5 ° intervals in the range of 0 ° ≦ φ ≦ 360 °. It is a flowchart showing a flow of calculation by computer simulation according to this embodiment. It is a diagram illustrating a radiation pattern angle distribution in order m = 3. It is a diagram illustrating a radiation pattern angle distribution in order m = 4. Distribution LEE change ratio at theta = 5 ° representing the light of goodness selects a 300% or more of R / a, and its degree m is a diagram showing the radiation pattern angle distribution. It is a diagram showing a state of TE light reflected by the photonic crystal. Between 1 st PB-2 nd PB, 3 rd between PB-4 th PB, 5 th PB-6 between th PB, 7 th PB-8 th PB between the photonic band gap (PBG) a其s PBG1, PBG2, PBG3, and PBG4, a diagram showing the relationship between R / a and PBG. The vertical axis (ωa / 2πc) in terms of the wavelength lambda V in vacuum, the photonic band structure of the lambda V and ka / 2 [pi in order m = 1 Bragg condition is satisfied sixth photonic band (6 th PB) is a diagram illustrating a. The vertical axis (ωa / 2πc) in terms of the wavelength lambda V in vacuum, the photonic band structure of the lambda V and ka / 2 [pi in order m = 1 Bragg condition is satisfied eighth photonic band (8 th PB) is a diagram illustrating a. And 5 integral multiples in terms of wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied sixth photonic band (6 th PB), vertical axis: 3 [lambda] V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. And 6 integral multiple in terms of the wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied sixth photonic band (6 th PB), vertical axis: 3 [lambda] V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. And 6 integral multiple in terms of the wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied sixth photonic band (6 th PB), vertical axis: 4.lamda V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. And 7 integral multiple in terms of the wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied sixth photonic band (6 th PB), vertical axis: 4.lamda V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. And 8 integral multiples in terms of the wavelength lambda V in vacuum vertical axis (ωa / 2πc) Bragg condition is satisfied sixth photonic band (6 th PB), vertical axis: 4.lamda V, the horizontal axis: ka / it is a diagram showing a photonic band structure of 2 [pi. Finite Difference Time Domain method is a diagram showing a calculation model calculated by (FDTD method) (Hall). Using a transfer technology by nanoimprint lithography method using a two-layer resist is a diagram showing a state of manufacture of the photonic crystal periodic structure having a fine pattern of nm order.

Hereinafter, embodiments for implementing the present invention will be described in detail with reference to the drawings. The structure and composition material of the LED element in the embodiment mentioned below, the shape of the periodic structure (pillar structure, Hall structures, etc.) and the like are not limited to, within the scope of exhibiting the effects of the present invention it can be changed as appropriate. Further, the embodiment also, without departing from the scope of the object of the present invention can be carried out appropriately changed. Further, for example, a design program of periodic structures, also including processed die in accordance with the present invention, are included in the present invention.

Embodiments of the present invention, a semiconductor light emitting device having a photonic crystal periodic structure having a reflective film on the surface of the GaN substrate (the side), consists of two structures having different refractive index to the GaN substrate back surface (side) a relates, above the photonic crystal periodic structure has a high light extraction efficiency from the GaN substrate back side, and is intended to provide a method of manufacturing and excellent light-emitting element light distribution.

(First Embodiment)
It will be described first light-emitting element according to a first embodiment of the present invention.

Photonic crystal periodic structure is composed of two structures having different refractive index, and the period a and the radius R is its periodic structure parameters are designed under the Bragg condition is satisfied the relationship between the wavelength λ that. If the interface is plural, a structure designed independently at each photonic crystal periodic structure.

Figure 1 is a structural cross-sectional view showing a configuration example of a light emitting device according to the present embodiment (FIG. 1 (a)) and a plan view viewed from the back side (Figure 1 (b)). The light-emitting element shown in FIG. 1 is a GaN substrate LED. GaN substrate LED shown in FIG. 1 (a), in order from the opposite side (surface side) and the GaN substrate, for example, an Al reflective film 1, an ITO transparent electrode 3, a p-type GaN layer 5, GaN active layer and (light emitting layer) 7, an n-type GaN layer 11, the GaN substrate 15, and a photonic crystal structure (phc) 17, a. AlGaN layer may also be present.

This structure, main light extraction surface in the flip-chip structure comprising a GaN substrate 15 backside, creating a photonic crystal structure 17 on the GaN substrate 15 backside. As shown in FIG. 1 (b), the photonic crystal structure (phc) 17 is formed on the rear surface 15a of the GaN substrate 15, made of a GaN pillar structure 17a and the air 17b.

Here, the radius of GaN pillar structure 17a and R, when the period is a, for example, the period a and the radius R of the ratio (R / a), of the reflection and light transmission in the periodic structure of wavelength lambda, either is a value determined depending on whether this optimization focuses on.

For example, if an object to greater than through the reflection of light at the interface is a R / a values ​​determined by focusing on the TE light. This electric field of the TE light is readily accumulates in the connection structure of the dielectric that lies parallel to the periodic structure surface, when a periodic structure parameters and the design wavelength satisfying the Bragg condition is reflected by the Bragg diffraction in the field plane It is considered to be due to.

Conversely, the ratio of the period a and radius R (R / a), when an object to larger than the reflection light transmission at the interface is the R / a values ​​determined by focusing on TM light . This electric field of the TM light is readily accumulates in dielectric spots present vertically in a periodic structure surface, the periodic structure parameters and the design wavelength may satisfy the Bragg condition is reflected by the Bragg diffraction in the electric field plane, i.e. the period probably due to permeation to the structure surface.

Each periodic structure parameter, the period a and the radius R determined from R / a in accordance with the order m of the Bragg condition, and, using the FDTD method for performing depth h of the above periodic structure 0.5a as a variable the analysis results of the simulation, the light extraction efficiency of the entire semiconductor light emitting element is the last determined values ​​so that the maximum for the wavelength lambda. Here, the depth h of the periodic structure having a depth greater than 0.5a is a value also the upper limit is limited by the actual machining accuracy.

In the photonic crystal periodic structure according to the present embodiment, the ratio of the period a and radius R (R / a) is a value determined as transmission effect of the light is improved on the basis of the photonic band of the TM light . And such structure, for example, a so-called pillar structure formed through the medium of smaller refractive index structure of large refractive index (air, etc.) (GaN pillar).

In this embodiment, the optimization of the parameters of the periodic structure may be considered the transmitted light with respect to TM light purposes permeation (see Figure 2).

As shown in FIG. 2, the electric field of the TM light is likely remain in the dielectric spots present vertically between pillar structure rod (pillar) 17a, when the average refractive index n av, the period a and the design wavelength λ Bragg condition is satisfied , it can be appreciated from the scattered by Bragg diffraction in a field plane, i.e. the TM light for the periodic structure surface in the present embodiment (the interface 15a) is transmitted.

Effective way to know the physical properties of the photonic crystal according to TM light is to analyze to obtain a photonic band (PB) structure from the plane wave expansion method. Eigenvalue equation of TM light is derived from Maxwell's equations in the following manner.

Figure JPOXMLDOC01-appb-I000001

However, E '= | k + G | E (G), ε: dielectric constant, G: reciprocal lattice, k: wave number, omega: Frequency, c: speed of light, E: is a field.

Reciprocal lattice (G) is present in numerous but, G the origin and the reciprocal lattice points take minimum distance, in the case of a triangular lattice photonic crystal G = ± b1, ± b2, 6 pieces of ± (b1 + b2) in and, as shown in FIG. 3, the first Brillouin region hexagonal obtained.

In FIG. 3, Γ, M, K point is called the point of symmetry. It indicates no grating band structure in a uniform medium obtained in the area having a symmetry point in FIG. 4 shows a photonic band (PB) structure of the photonic crystal in Fig.

Each PB from the primary to the seventh-order 5 is a scattered wave wavevector k + G.

Incidentally, the respective PB is because it was created by rearranging the eigenvalues ​​from low rank energy does not necessarily coincide with the wave vector of the non-lattice photonic band.

Comparing Figure 4 and Figure 5, in Figure 5, it can be seen that significant photonic band gap in a symmetric point (PBG) is observed.

For example, although solution at Γ point in the non lattice state of FIG. 4 is degenerate sextet, degeneracy solved in Γ point in the photonic crystal structure of FIG. 5, six waves make standing wave. In the photonic crystal structure of FIG. 5, likewise, two waves melt double degeneracy in M ​​points of standing waves, three waves melts triple degeneracy in point K to make the standing wave, respectively.

In these symmetry points, it occurs group velocity anomaly (dω / dk = 0), the propagation direction of the light changes. Therefore, it is possible to obtain a guideline for light extraction efficiency and light distribution optimizing the photonic crystal by focusing on the physical properties of the light at each point of symmetry of the photonic band.

Therefore, gamma point, M point, attention is paid to the photonic band resulting standing wave (PB) at point K. This is because, the larger the refractive index difference at the interface, in the case of the TM light is because PBG occurs more than several.

Hereinafter, the outline of the flow of processing by the computer simulation was conducted in view of the above problems.

Figure 13 is a flowchart showing a flow of calculation by computer simulation according to this embodiment.

(Step S1)
In step S1, in a range of 0.18 ≦ R / a ≦ 0.40, R / a (R: diameter, a: period), for example varying in 0.01 steps.

(Step S2)
Satisfies the condition scattered waves Bragg correspond to any of the photonic band (PB), to associate the period a to transmit the design wavelength λ in the Bragg equation. Here, the photonic band of interest is the Bragg condition is satisfied scattered wave (k + G).

That is, in step S2, and calculates an average refractive index n av from the refractive index n 1, n 2, R / a structure, a and R each order into equation mλ / n av = 2a Bragg m decide.

here,

Figure JPOXMLDOC01-appb-I000002
It is.

The period a according to the definition of the photonic crystal is close to the wavelength lambda, the period in order m = 3 and 4 correspond to this wavelength region.

For example, in R / a = 0.34 (m = 4) can be calculated as follows.

Figure JPOXMLDOC01-appb-I000003
It is.

Thus, a n av = 1.79. Order m = 4 in the Bragg equation, and substituting a wavelength = 455 nm in vacuum becomes a = 509 nm. Moreover, consisting of R / a = 0.34 and d = 346 nm.

(Step S3)
In step S3, the determined R / a, wavelength lambda, the dielectric constant epsilon 1, the epsilon 2 determined from the refractive index n 1, n 2, to obtain the photonic band (PB) structure of the TM light by the plane wave expansion method. PBG1, PBG2, orders corresponding to the maximum value of PBG3 is a candidate for optimizing the R / a is m = 3 ~ 4.

Between 1 st PB-2 nd PB, between 3 rd PB-4 th PB, photonic bandgap between 5 th PB-6 th PB to (PBG) and其s PBG1, PBG2, PBG3, and R / a and PBG It shows the relationship in Figure 6.

As shown in FIG. 6, R / a = 0.19, R / a = 0.23, the R / a = 0.32, the maximum value of the photonic band gap can be obtained. Since the size and the light extraction efficiency of the photonic band gap are correlated, R / a obtained from FIG. 6 is a promising candidate for optimization regardless of order.

(Step S4)
The vertical axis of the Bragg condition is satisfied second photonic band (2 nd PB) and fourth photonic band (4 th PB) to (ωa / 2πc) in terms of the wavelength lambda V in vacuum, in order m = 1 obtain the photonic band structure of λ V and ka / 2π. The vertical axis can be converted ωa / 2πc = a / λ PhC ( However, lambda PhC is the wavelength of the photonic crystal (PhC)). Therefore λ V = λ 1 = a 1 / (ωa / 2πc) × n av also, Bragg equation, i.e., is derived as from 1 × λ V / n av = 2a 1 a 1 = λ v / 2n av . The reason for selecting the second photonic band (2 nd PB) and fourth photonic band (4 th PB) is a PBG1 and PBG2 is 0.18 ≦ R / a ≦ 0.40 as shown in FIG. 6 large opening, the second photonic band (2 nd PB) and fourth photonic band (4 th PB) occurs a standing wave at each point of symmetry, it is then because changing the direction of light propagation.

These FIG. 7A, FIG. 7B. The second photonic band (2 nd PB) results in a standing wave at each point of symmetry R / a, is that the R / a of closest or meet at a wavelength 455nm and a point in a vacuum. Therefore, when read from FIG. 7A is a Γ point R / a = 0.37, the M point R / a = 0.21, the R / a = 0.26 in the K point. In Figure 7B, no standing waves since neither approach the wavelength 455nm in vacuum either R / a In 0.18 ≦ R / a ≦ 0.40.

(Step S5)
First consider the R / a, which is determined by the order m = 3. As shown in FIG. 8A, Step 4 of R / a = 0.37 (order m = 1) of the second photonic band (2 nd PB) results in a standing wave. Cycle length of order m = 3 produces a standing wave having three abdominal Since the phase becomes 3 integral multiple of the period length of m = 1 is maintained. Thus, λ 3 = a 3 / ( ωa / 2πc) × n av, a 3 = 3λ V / 2n av. It is.

Period in m = 3 is three times the period of the m = 1. Thus the magnitude of the wavelength of the vertical axis is also the wavelength lambda V × 3 in vacuum (degree m).

The standing wave produces a R / a wavelength × 3 = 1365nm and closest to R / a next or meet at a point, as well as Γ point and order m = 1 in the vacuum at each point of symmetry (R / a = 0.37), M point (R / a = 0.21), K point (R / a = 0.26), and becomes candidates for optimization. A second photonic band (2 nd PB) vacuum wavelength × 3 about (order) and the wave number of the photonic band structure shown in Figure 9A.

On the other hand, the frequency of the fourth photonic band at m = 1 (4 th PB) is a little less than twice higher than the frequency of the second photonic band (2 nd PB). The standing wave does not occur in any of the R / a in 0.18 ≦ R / a ≦ 0.40. However, the order becomes m = 3 when it comes to a certain cycle length is increased in proportion to the degree R / a in phase produces a standing wave. As shown in FIG. 8B, the conditions fourth photonic band of a R / a (4 th PB) results in a standing wave, m = 1, the 4 integral multiple and 5 integer period length of a R / a a fold produces a standing wave having a 其 s four antinodes and five ventral in periodic length of m = 3.

Therefore, in order to determine the R / a most approaching or in contact with a point on the wavelength × 3 = 1365nm in vacuum at each point of symmetry, the fourth photonic band (4 th PB of all R / a obtained in step S4 4 that an integral multiple of a) shown in FIG. 9B, FIG. 9C those five integral multiple. 4 gamma point an integer multiple (R / a = 0.31), M point (R / a = 0.31), a K-point (R / a = 0.36). 5 integer in multiples Γ point (N), M point (R / a = 0.18), K point (R / a = 0.27), and the both become candidates for optimization.

(Step S6)
In order m = 4, a λ 4 = a 4 / (ωa / 2πc) × n av, a 4 = 4λ V / 2n av. A second photonic band (2 nd PB) vacuum wavelength for the wave number of the photonic band structure shown in FIG. 10A. Closest to R / a similarly Γ point and order m = 1 to the wavelength × 4 = 1820nm in vacuum at each point of symmetry (R / a = 0.37), M point (R / a = 0.21) , a K-point (R / a = 0.26). The condition of the fourth photonic band of a R / a (4thPB) results in a standing wave, 5 integral multiple of the incident wavelength at m = 1, 6 integral multiple is 7 integral multiple. Therefore when seeking wavelength × 4 = closest together or meet at a point in the 1820nm R / a in the vacuum at each point of symmetry, gamma point 5 integral multiple (R / a = 0.35), M point (R / a = 0.34) is. Is a K point corresponding to the 4 th PB in FIG. 5 when the longitudinal axis of the fourth photonic band re-converted to .omega.a / 2.pi.c in order m = 1 (R / a = 0.40) ( Figure 10B). The 6 integral multiple a Γ point (R / a = 0.20) M points (R / a = 0.27) K point (R / a = 0.31) (Figure 10C). Γ point 7 integral multiple (N) M points (N) K point (R / a = 0.24) becomes (FIG. 10D), both the optimization of the candidate.

(Step S7)
Light extraction efficiency change rate of the photonic crystal corresponding to the obtained R / a in step S2 and the light distribution, and 0.18 ≦ R / a ≦ 0.40 made orders all R / a m = 3 calculated by the finite-difference time-domain method (FDTD method) in 4. Regarding depth select any value greater than 0.5 times the greatest period a in order m = 3 ~ 4.

Figure 11 shows the calculation model.

Al reflective film in a flip-chip structure, ITO transparent electrode, p-GaN layer, light emitting layer, n-GaN layer, and a GaN substrate. Light emitted from the light emitting layer is mainly emitted from the GaN substrate back surface and the side wall to the outside. Central wavelength 455 nm, a polarization degree 0.94. The photonic crystal is formed on the GaN substrate back surface. Output 1 photonic crystal is not LED output, the light extraction efficiency and the output 2, output of the photonic crystal is there LED (LEE) rate of change is calculated as follows. That is calculated by LEE change ratio = (output 2 output 1) / Output 1 becomes far field (Far Field) and near field (Near Field). Further, radiation pattern to verify the light distribution is calculated in the far field.

Field intensity E total at the point P 1 as shown in FIG. 12 E total = | is defined as 2 | E θ | 2 + | E φ. The field strength is proportional to the intensity of light. Therefore it is possible to obtain the radiation pattern by calculating at 5 ° intervals in a range of electric field intensity in this respect P 1 of 0 ° ≦ θ ≦ 180 °, 0 ° ≦ φ ≦ 360 °.

Figure JPOXMLDOC01-appb-T000004

Figure JPOXMLDOC01-appb-T000005

The results of simulation in the FDTD method for each R / a in m = 3 and m = 4, set forth in Table 1 and Table 2. LEE change ratio and (Far Field @ 455nm) refers to the change rate of the LED element in the calculated wavelength 455nm at the far field. LEE change ratio and (Near Field @ 455nm) refers to the change rate of the LED element at a wavelength of 455nm which is calculated by the near field. LEE change ratio and (θ = 5 °) integrates all the range of output 0 ° ≦ φ ≦ 360 ° in theta = 5 ° of the radiation pattern, it refers to a rate of change compared with and without the photonic crystal. Photonic band (PB) state and the second photonic band (2 nd PB) and fourth photonic band that are candidates for photonic crystal optimization determined in Step 3-6 (4 th PB) each symmetric point It shows the state in.

Further, the radiation pattern angle distribution of each order m is shown in FIGS. 14 and 15. The FDTD method is performed calculations in 5 ° steps with θ direction and φ directions in polar coordinates. The intensity of light at each area element in this case polar coordinates is represented by Sinshitadishitadifai. However, the area of ​​the detector in the actual light distribution measurement discrepancies with changes in angle θ occurs between the two for a constant. Accordingly, here, the intensity of the vertical axis displays a relative power per unit area. With respect to the horizontal axis displays the output of the angle θ by all integrated phi in the range of 0 ° ≦ φ ≦ 360 °.

(Step S8)
From the light extraction efficiency (LEE) rate of change is larger R / a and the order m, selects the R / a and order m corresponds to light distribution purposes. Hence parameters of the photonic crystal optimization, diameter, period, depth is determined. In the range of steps S3 ~ S6 becomes resulting photonic crystal optimization candidate R / a and 0.18 ≦ R / a ≦ 0.40 Compare R / a other than the candidate. As a result settles to the resulting R / a of optimizing candidate in step S3 ~ S6.

From Table 1 and Table 2, in LEE change rate of the LED elements more than 65%, for example LEE change ratio at theta = 5 ° representing the goodness of light distribution selects 300% or more of R / a and order m FIG. 16 shows the radiation pattern angle distribution Te. In addition, the following micron pattern shape to be used in PSS (Patterned Sapphire Substrate) compared with simulation FDTD method. Shape with a cone-type pillar sidewall angle 60 ° (upper / lower / period / depth) = (267nm / 1200nm / 1800nm ​​/ 800nm), are arranged in a triangular lattice shape. As is apparent the photonic crystal optimization ideas R / a from 16 results with even better as compared to the light extraction efficiency and light distribution properties to other R / a and micron pattern was obtained. Especially shows R / a = 0.34 (order m = 4) most light distribution with good results in the above pattern θ = 0 ° ~ 15 ° of. Thus by performing the processing in step S8 from step S1, it is possible to easily optimize the light extraction efficiency and light distribution of the photonic crystal.

Incidentally, when determining the structure of the optical semiconductor element to be actually manufactured, can be determined on the basis of the optimized values, without using an optimized value itself, also structure it using values ​​close this it is intended to fall within the scope of the invention.

Meanwhile, the light of the LED TE light and TM light propagates medium while elliptically polarized. So also discussed below how the TE light incident on the photonic crystal.

As shown in FIG. 17, the electric field of the TE light is easily remain between parallel pillar structure rod photonic crystal plane, when the average refractive index n av, the period a and the design wavelength λ Bragg condition is satisfied, the electric field plane It is reflected by the Bragg diffraction in. Physical properties of the photonic crystal according to the TE light is analyzed to obtain the photonic band (PB) structure of the following Maxwell equation by the same steps as the TM light (Step S1 ~ 3).

Figure JPOXMLDOC01-appb-I000006

However, epsilon: dielectric constant, G: reciprocal lattice, k: wave number, omega: Frequency, c: light speed, H: is the magnetic field.

Between 1 st PB-2 nd PB, 3 rd between PB-4 th PB, 5 th PB-6 between th PB, 7 th PB-8 th PB between the photonic band gap (PBG) a其s PBG1, PBG2, PBG3, and PBG4, showing the relationship between R / a and PBG in Figure 18.

Compared to PBG for the TM light and the TE light PBG1 and PBG2 is absent. Therefore reflection effect of the TE light is absent standing waves in these photonic band is weakened. Further, PBG3 is present is PBG in 0.28 ≦ R / a ≦ 0.39, its size is very small compared to the PBG for the TM light. PBG4 is present is PBG in 0.20 ≦ R / a ≦ 0.25, but likewise its size is very small. However, PBG3 the R / a = 0.34, PBG4 is a slight at R / a = 0.22 is because 其 s maximum value is obtained, the major candidate for optimization.

Next, similarly to step S4 of TM light, converts the vertical axis of the Bragg condition is satisfied sixth photonic band (6 th PB) and eighth photonic band (8 th PB) to the wavelength lambda V in vacuum and, to obtain a photonic band structure in order m = 1 shown in FIGS. 19 and 20. Any of R / a standing wave does not occur because it does not approach the wavelength 455nm in vacuum also. Furthermore, it analyzes same (steps S5-S6) and TM light in order m = 3 and the order m = 4, the condition is satisfied photonic band structure caused a standing wave shown in FIGS. 21 to 25. When strong candidate for optimization of m = 3, 5 integral with the multiple Γ of the sixth photonic band (R / a = 0.33), K point (R / a = 0.36), the 6 integral multiple in point M (R / a = 0.29), the eighth photonic band was not appropriate. Similarly, when the m = 4, the 6 integral multiple of the sixth photonic band, gamma point (R / a = 0.38), Γ point 7 integral multiple (R / a = 0.31), M point ( R / a = 0.35), K point (R / a = 0.32), at the point M is 8 integral multiple (R / a = 0.29), the eighth photonic band was not applicable.

R / a of the resulting optimized candidate analysis TE light is reflected in the LED inside the photonic crystal, the reflection effect because energy generated standing waves small size of each PBG is small TM weaker than the transmission effect of light. This can be understood also from the fact that in good agreement with the order m = 3 and m = the FDTD analyzed in 4 of increase or decrease of the light extraction efficiency results. Furthermore, since the light of the GaN-based blue LED was grown on a sapphire C-plane are almost TE polarized, the polarization degree of the light sources in the analysis of the FDTD according to this embodiment was 0.94. This is the intensity of the TE light is 10 times or more of the TM light, generally in many cases to form a favorable photonic crystal (holes) in the TE light. However, decrease of the light extraction efficiency of the analysis results in the photonic crystal (pillar) of a very high effect, to design the structure of the photonic crystal according to the processing location of the light extraction surface regardless TE light and TM light suggesting the importance of the thing.

Therefore, we analyzed a plane wave expansion method, the hole of the R / a = 0.40 to PBG is maximum in the TE light is formed on the GaN substrate back side as shown in FIG. 26, the light extraction efficiency FDTD method of the pillar under the same conditions the analysis of the percentage change was carried out. However, the order m = 4, the diameter = 407 nm, period = 508 nm, a depth = 500 nm, satisfies the Bragg condition with respect to the design wavelength 455 nm. Decrease of the light extraction efficiency results that 65% was obtained. This value was slightly deteriorated as suggested in comparison with optimized pillar structure.

Next, a method for manufacturing the photonic crystal structure. Nanoimprint has excellent technique for collectively transferring a large area photonic crystal pattern of the mold to organic resist was spin-coated onto the substrate. Further, even if the substrate by utilizing the resin film mold warped about several hundred microns are possible transfer. However, organic resist nanoimprint, the etching selectivity to the material a pattern forming portion in order to emphasize the fluidity is not necessarily sufficient. The pattern size and pattern forming portion size after etching the mold do not match. Therefore, to implement the process using a two-layer resist in order to solve this problem as follows.

A step of spin-coating a large lower resist etch selectivity to the substrate on the substrate, an upper resist having a fluidity and oxygen resistance function was spin-coated on the lower resist, and transferring the photonic crystal pattern thereon a step of imparting oxygen resistance exposing the patterned upper resist in oxygen plasma, and performing a pattern forming a lower resist in an oxygen plasma a patterned upper resist having the oxygen resistance as a mask, the patterned lower resist and dry etching the substrate by ICP plasma as a mask to form a photonic crystal.

By varying the thickness of the lower resist if this method, it is possible to the depth of the mold pattern obtaining etching depth of about 2-fold (the case of GaN). Further, by changing the oxygen plasma conditions during mask formation of the lower resist by upper resist, it is possible to make the diameter adjustment of the order of 30% with respect to the diameter of the mold pattern.

It will be described more detailed manufacturing process. To get a good light extraction efficiency, it is necessary to form a working order of nm as calculated.

Accordingly, shown using a two-layer resist that combines features of both flowability and etch selectivity, using a transfer technology by nanoimprint lithography, a photonic crystal periodic structure having a fine pattern of nm order in FIG. 27 as, for example, and transferred to the GaN substrate back surface.

The design wavelength is lambda, at least, the Al reflective electrode 1, and the p-type GaN layer 5, a p-type GaN light-emitting layer 7, and the GaN substrate 15 surface to prepare a layered structure containing in this order from the opposite side , the Al reflective electrode 1 of GaN substrate 15 is prepared a mold for forming a photonic crystal periodic structure 17 on the opposite side, the GaN substrate 15 on the surfaces of, forming a resist layer, transferring the structure of the mold and, by etching the GaN substrate 15 surface to form a photonic crystal periodic structure 17 using the resist layer as a mask. This will be described with reference to the following Figure 27.

First, create a mold for reproducing the optimized periodic structure by the practice of the present invention accurately on the GaN substrate. The mold can also be used a resin mold to be able to follow the substrate warp of as shown in FIG. 27 (b).

Next, spin coating a large organic underlayer resist etch selectivity to GaN substrate to a thickness g. Note that the thickness g is selectively determined according to the etching selection ratio of the lower resist against GaN substrate. Thereafter, spin coating a silicon-containing upper layer resist having a fluidity and oxygen resistant features on the lower resist surface at a predetermined thickness (Fig. 27 (a)).

Next, the upper resist, the pattern of the mold is transferred by using the nanoimprint apparatus (FIG. 27 (b)).

Then, exposing the upper layer resist mold pattern is transferred to the oxygen plasma, as well as provides oxygen resistance, to remove the residual film of the upper layer resist remaining in nanoimprinting transfer. (FIG. 27 (c)).

Next, an upper resist having oxygen resistance as a mask, the organic underlayer resist was etched by oxygen plasma, the GaN substrate to form a pattern mask for dry etching (FIG. 27 (d)). The diameter d 1 of the GaN substrate side of the pattern mask according to FIG. 27 (e), by adjusting the conditions of the oxygen plasma may be fine-tuned within the range of about 30% of d 1.

The GaN substrate was dry-etched by ICP plasma through a pattern mask, forming the optimized periodic structure is made (FIG. 27 (e)).

If periodic structure by the pillar structure, the shape after etching generally becomes d 1 <d 2 trapezoidal as shown in FIG. 27 (f), the side wall angle is dependent on the etching selectivity of the organic underlayer resist. Incidentally, according to this embodiment, by changing the thickness g of the organic underlayer resist, easily depth of the photonic crystal periodic structure formed on the GaN substrate after dry etching, to a depth of the mold it can be a depth of about 1.5 times.

Further, by changing the diameter d 1 at the time of pattern mask formation, the diameter of the periodic structure can be easily changed about 30%. It is possible to replace the remake of the mold, contributing to production time and cost savings of the mold, the cost on a large merit of manufacturing the semiconductor light emitting device thus.

Processing and control may be realized by hardware processing by CPU-based software processing (Central Processing Unit) or a GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

Further, in the above embodiment, the configuration such as depicted in the accompanying drawings, the invention is not limited thereto, but can be appropriately modified within the scope of exhibiting the effects of the present invention. Further, the invention is capable of being carried into practice with modifications thereof as appropriate without departing from the scope of the invention.

The constituent elements of the present invention can be sift optionally invention having a configuration in which selection is also included in the present invention.

Also, a program for implementing the functions described in this embodiment may be recorded on a computer readable recording medium, to read the program recorded in this recording medium into a computer system, processing of each by executing it may be carried out. Here, the term "computer system" includes an OS and hardware such as peripheral devices.

In addition, the "computer system" is, in the case you are using the WWW system, a homepage providing environment (or display environment) is also included.

The "computer-readable recording medium" refers to flexible disks, magneto-optical disks, ROM, portable media such as a CD-ROM, and a storage device such as a hard disk built in the computer system. Furthermore, the "computer-readable recording medium" is held as a communication line when transmitting a program via a communication line such as a network or a telephone line such as the Internet, a short period of time, a dynamic program things, such as a volatile memory inside a computer system serving as a server or a client in that case, and also includes those that holds the program for a certain time. The program may be one for implementing part of the above functions, may further be implemented in combination with a program already recorded above functions in a computer system. At least a portion of the functions may be realized by hardware such as an integrated circuit.

All publications cited herein shall be incorporated herein patents and patent applications as reference.

The present invention can be used as a semiconductor light-emitting device.

a: period of the photonic crystal periodic structure, R: radius of the periodic structure, h: the periodic structure processing depth, 1: Al reflective electrode (film), 3: ITO transparent electrode, 5: p-GaN layer, 7: emitting layer, 11: n-GaN layer, 15: GaN substrate, 15a: surface, 17a: GaN pillar structure, 17b: air, 17: phc.

Claims (13)

  1. Has a reflective film on the surface of the GaN substrate (the side), a semiconductor light emitting device having a photonic crystal periodic structure consisting of two structures having different refractive index to the GaN substrate back surface (side),
    The photonic crystal periodic structure,
    Period a and radius R which is a parameter of the design wavelength lambda V and the periodic structure in the vacuum satisfies the Bragg condition,
    R / a is,
    In the range from 0.18 to 0.40, the semiconductor light-emitting element having two photonic band gap within the fourth photonic band (4 th PB) in the photonic band structure of TM light.
  2. The R / a is,
    The device according to claim 1 in order m = 3 or 4 which is a value corresponding to the maximum value of each photonic bandgap.
  3. The R / a is,
    In order m = 3 or 4, when the longitudinal axis of the photonic band structure (ωa / 2πc) is converted to the wavelength lambda V in vacuum, a point of symmetry of the second photonic band (2 nd PB) Γ point, M point, the semiconductor light-emitting device according to claim 1 which is closest to the value or meet at a wavelength lambda V × m and the point in the vacuum in any of the K point.
  4. The R / a is,
    When orders m = 3, the wavelength lambda V × 3 in a vacuum of the longitudinal axis of the photonic band structure (ωa / 2πc) were fourth photonic band (4 th PB) and 4 integer multiples and 5 integral multiple the device according to claim 1 which is one of closest value or contact with symmetry points and points on the fourth photonic band (4 th PB).
  5. The R / a is,
    When orders m = 4, the wavelength lambda V × 4 in the vacuum of the longitudinal axis of the photonic band structure (ωa / 2πc) is a fourth photonic band (4 th PB) 5 integral multiple, 6 integral multiple, the device according to claim 1 7 is closest to the value or contact either of symmetrical point and the point on the integral multiplied by the fourth photonic band (4 th PB).
  6. Parameters of each periodic structure,
    A photonic crystal composed of the R / a and 0.5a more depth h selected calculated by the FDTD method, the light extraction efficiency and light distribution is the last determined parameter to be optimized according the device according to any one of claim 1 to 5.
  7. The structure,
    The semiconductor light-emitting device according to any one of claims 1 to 6, which is a structure forming a structure having a refractive index greater in a medium of smaller refractive index.
  8. A parameter calculation method of the photonic crystal periodic structure in a semiconductor light-emitting device according to any one of claims 1 to 7,
    The ratio of the radius R of the parameter a is the period a and the structure of the periodic structure (R / a) a first step of temporarily determined,
    Each of the refractive index n 1 and n 2 of the structure, and to calculate the average refractive index n av from these and the R / a, which was substituted into the equation of Bragg conditions, the degree m = 3 and m = 4, a second step of obtaining a period a and radius R,
    By the R / a and the wavelength λ and the refractive index n 1 permittivity ε1 and epsilon 2 of plane wave expansion method using each structure obtained from, n 2, a third analyzing the photonic band structure of TM light and the step,
    Second photonic band TM light vertical axis (2 nd PB) and fourth photonic band (4 th PB) to (ωa / 2πc) in terms of the wavelength lambda V in vacuum, in order m = 1 lambda V a fourth step of obtaining a photonic band structure of the ka / 2 [pi and,
    For orders m = 3 and m = 4, the wavelength lambda V × m and the point in the vacuum at each symmetry points in the second photonic band TM light (2 nd PB) and fourth photonic band (4 th PB) seeking R / a either closest contact, a fifth and sixth step of the optimization of the candidate, the light distribution and light extraction efficiency change rate of the photonic crystal corresponding to the R / a, 0.18 ≦ the R / a ≦ 0.40 becomes all R / a is calculated in order m = 3 and 4 in a finite-difference time-domain method (FDTD method), the largest period a in order m = 3 ~ 4 with respect to depth a seventh step of selecting an arbitrary value of 0.5 times or more of,
    Parameter calculation method of the photonic crystal periodic structure is characterized by having a.
  9. A parameter calculation method of the photonic crystal periodic structure in a semiconductor light-emitting device according to any one of claims 1 to 7,
    The ratio of the radius R of the parameter a is the period a and the structure of the periodic structure (R / a) a first step of temporarily determined,
    Each of the refractive index n 1 and n 2 of the structure, and to calculate the average refractive index n av from these and the R / a, which was substituted into the equation of Bragg conditions, the degree m = 3 and m = 4, a second step of obtaining a period a and radius R,
    By the R / a and the wavelength λ and the refractive index n 1 permittivity ε1 and epsilon 2 of plane wave expansion method using each structure obtained from, n 2, a third analyzing the photonic band structure of TM light and the step,
    Second photonic band TM light vertical axis (2 nd PB) and fourth photonic band (4 th PB) to (ωa / 2πc) in terms of the wavelength lambda V in vacuum, in order m = 1 lambda V a fourth step of obtaining a photonic band structure of the ka / 2 [pi and,
    For orders m = 3 and m = 4, the wavelength lambda V × m and the point in the vacuum at each symmetry points in the second photonic band TM light (2 nd PB) and fourth photonic band (4 th PB) seeking R / a either closest contact, a fifth and sixth step of the optimization of the candidate, the light distribution and light extraction efficiency change rate of the photonic crystal corresponding to the R / a, 0.18 ≦ the R / a ≦ 0.40 becomes all R / a is calculated in order m = 3 and 4 in a finite-difference time-domain method (FDTD method), the largest period a in order m = 3 ~ 4 with respect to depth a seventh step of selecting an arbitrary value of 0.5 times or more of,
    From the light extraction efficiency (LEE) rate of change is larger R / a and the order m, and select the R / a and order m corresponds to the light distribution of the object, to determine the diameter, the period, the depth, the first 3 steps and an eighth step of selecting a good parameter of orientation by comparing the sixth the resulting photonic crystal optimization candidates to S R / a and other R / a,
    Parameter calculation method of the photonic crystal periodic structure is characterized by having a.
  10. The device according to claim 1, wherein the photonic crystal periodic structure is characterized in that which has been processed using a transfer technology by nanoimprint lithography.
  11. The transfer of the photonic crystal periodic structure by nano-imprint lithography method, coated with a large lower resist etch selectivity with respect to the structure of the processing target, to coat the top layer resist having a fluidity and oxygen resistance thereon, the two the device according to claim 10, characterized in that a transfer technique using a layer resist method.
  12. A method of manufacturing a semiconductor light emitting element,
    The design wavelength is lambda, a step of preparing a reflective electrode layer, and the p-type GaN light-emitting layer, a laminated structure containing in this order from the side opposite to the a GaN substrate plane,
    Preparing a mold for forming a photonic crystal periodic structure on the opposite side to the reflective electrode layer of the GaN substrate,
    On the GaN substrate surface, a step of the resist layer is formed, and transferring the structure of the mold,
    The method of manufacturing a semiconductor light emitting device and a step of forming an etching to the photonic crystal periodic structure from the GaN substrate surface using the resist layer as a mask.
  13. On the GaN substrate surface, a resist layer is formed, and a step of transferring a structure of the mold,
    On the GaN substrate surface to form a highly liquid first resist layer, and high etch selectivity second resist layer for the first resist layer, dry etching using a two-layer resist method in accordance with and a step,
    Includes a step of transferring a structure of the mold on the first resist layer using a nano-imprint lithography, a,
    Forming a photonic crystal periodic structure by sequentially etching the GaN substrate surface using the resist layer as a mask, and the second resist layer and the first resist layer, the second resist layer is exposed with etched until, even combined etched pattern convex portions of the first resist layer,
    The method of manufacturing a semiconductor light emitting device according to claim 12, characterized in that it comprises a step of forming a photonic crystal periodic structure by sequentially etching the GaN substrate surface the second resist layer as a mask.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009033180A (en) * 2007-07-30 2009-02-12 Samsung Electro Mech Co Ltd Photonic crystal light emitting element, and manufacturing method thereof
JP2009081469A (en) * 2003-07-16 2009-04-16 Panasonic Corp Semiconductor light emitting apparatus and module mounted with the same
WO2013008556A1 (en) * 2011-07-12 2013-01-17 丸文株式会社 Light emitting element and method for manufacturing same
US20130161677A1 (en) * 2010-07-19 2013-06-27 Rensselaer Polytechnic Institute Integrated polarized light emitting diode with a built-in rotator
WO2013132993A1 (en) * 2012-03-07 2013-09-12 株式会社 アルバック Method for manufacturing element

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009081469A (en) * 2003-07-16 2009-04-16 Panasonic Corp Semiconductor light emitting apparatus and module mounted with the same
JP2009033180A (en) * 2007-07-30 2009-02-12 Samsung Electro Mech Co Ltd Photonic crystal light emitting element, and manufacturing method thereof
US20130161677A1 (en) * 2010-07-19 2013-06-27 Rensselaer Polytechnic Institute Integrated polarized light emitting diode with a built-in rotator
WO2013008556A1 (en) * 2011-07-12 2013-01-17 丸文株式会社 Light emitting element and method for manufacturing same
WO2013132993A1 (en) * 2012-03-07 2013-09-12 株式会社 アルバック Method for manufacturing element

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
CHOI ET AL.: "Design of an LED Chip Structure with an Integrated Two-dimensional Photonic Crystal to Enhance the Light- extraction Efficiency", JOURNAL OF KOREAN PHYSICAL SOCIETY, vol. 94, no. 10, May 2014 (2014-05-01), pages 1425 - 1429 *
DING ET AL.: "Improving the Vertical Light- Extraction Efficiency of GaN-Based Thin-Film Flip-Chip LEDs With p-Side Deep-Hole Photonic Crystals", JOURNAL OF DISPLAY TECHNOLOGY, vol. 10, no. 11, November 2014 (2014-11-01), pages 909 - 916, XP011561975, DOI: doi:10.1109/JDT.2013.2281236 *
KASHIMA ET AL.: "The micro machining process technology of nano imprint and dry etcing to improve the efficiency of nitride LED", IEICE TECHNICAL REPORT, vol. 114, no. 336, 20 November 2014 (2014-11-20), pages 27 - 32 *
KIM ET AL.: "Enhancement of light extraction from GaN-based green light-emitting diodes using selective area photonic crystal", APPLIED PHYSICS LETTERS, vol. 96, 22 June 2010 (2010-06-22), pages 251103.1 - 251103.3, XP012131642, DOI: doi:10.1063/1.3454240 *
LAI ET AL.: "Directional light extraction enhancement from GaN-based film-transferred photonic crystal light-emitting diodes", APPLIED PHYSICS LETTERS, vol. 64, 25 March 2009 (2009-03-25), pages 123106 - 1, XP012118528, DOI: doi:10.1063/1.3106109 *
ORITA ET AL.: "High-Extraction-Efficiency Blue Light-Emitting Diode Using Extended-Pitch Photonic Crystal", JAPANESE JOURNAL OF APPLIED PHYSICS, vol. 43, no. 8B, 25 August 2004 (2004-08-25), pages 5809 - 5813 *

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