WO2007136000A1

WO2007136000A1 - Light emitting device and method for manufacturing same

Info

Publication number: WO2007136000A1
Application number: PCT/JP2007/060247
Authority: WO
Inventors: Masami Aihara
Original assignee: Alps Electric Co., Ltd.
Priority date: 2006-05-22
Filing date: 2007-05-18
Publication date: 2007-11-29
Also published as: TW200802990A; JP2009193975A

Abstract

[PROBLEMS] To reduce loss of a light emitting quantity due to total reflection, by arranging a light transmitting layer having refraction index inclination on the surface of a semiconductor light emitting element in a light emitting device such as a light emitting diode or the like. [MEANS FOR SOLVING PROBLEMS] A semiconductor light emitting element (10) and electrodes (3, 4) mainly composed of Ga-N are arranged on a sapphire substrate (2). On the surface of the semiconductor light emitting element (10), a light transmitting layer (20) is arranged. The light emitting layer (20) is formed by a CVD method. Inside the light transmitting layer (20), oxygen concentration reduces and nitrogen concentration increases toward the semiconductor light emitting element (10). Therefore, the light transmitting layer (20) has a refraction index which becomes smaller as it separates from the semiconductor element (10).

Description

Specification

Light emitting device and manufacturing method thereof

Technical field

The present invention relates to a light-emitting device such as a light-emitting diode in which a light-transmitting layer that covers the surface of a semiconductor light-emitting element is formed and the refractive index of the light-transmitting layer is set to decrease as the power of the semiconductor light-emitting element increases. And a manufacturing method thereof.

Background art

[0002] A light-emitting device known as a light-emitting diode is such that when a forward current flows through a compound semiconductor with a pn junction, free electrons and free holes recombine, and light of a predetermined wavelength is generated by the energy at that time. To emit. With the chemical semiconductor power SGa-N (gallium 'nitrogen), light emission in the wavelength range from green to ultraviolet can be obtained, and with Ga-As-P (gallium' arsenic 'phosphorus), the red power also extends to yellow. Light emission in a range of wavelengths can be obtained, and red light emission can be obtained with Ga—Al—As (gallium • aluminum arsenic).

[0003] In this type of light emitting device, there is a large difference between the refractive index of air in which the refractive index of the compound semiconductor is high, and thus light emitted in the compound semiconductor is caused to flow between the compound semiconductor and air. As the probability of total reflection at the interface increases, the amount of light emission decreases. For example, Ga-N has a refractive index of about 2.5, and there is a refractive index difference of about 1.5 with air, so that the emission loss due to total reflection increases.

Therefore, in the light-emitting diode described in Patent Document 1 below, the surface of the light-emitting element section is covered in multiple layers with a plurality of types of light-transmitting sealing materials each formed of a different material. The By gradually lowering the refractive index of the sealing material from the light emitting element portion side toward the air side, a stepwise refractive index gradient is provided between the light emitting element portion and the air.

[0005] Further, in the light emitting diode described in Patent Document 2, the light emitting element portion is mainly composed of Ga-N, and is located on the light emitting side surface of the light emitting element portion! /, P-Ga- In the A1-N clad layer, the deposition amount ratio of Ga and A1 is changed in the film thickness direction, and the refractive index of the clad layer is gradually lowered in accordance with the direction of force on the active layer side.

Patent Document 1: JP 2001-203392 A Patent Document 2: JP-A-9 116192

Disclosure of the invention

Problems to be solved by the invention

[0006] In the light emitting diode described in Patent Document 1, since a plurality of sealing materials having different refractive indexes are provided on the surface of the light emitting element portion, multiple sealing materials are stacked. A forming process is required, and the manufacturing cost increases. In addition, since a difference in refractive index occurs at the interface between different sealing materials, it is inevitable that a loss of light emission occurs.

[0007] Further, in the light emitting diode described in Patent Document 1, DLC (diamond-like carbon) is used as a high refractive index material in close contact with the light emitting element portion. The cost of

[0008] In the light-emitting diode described in Patent Document 2, in the p-Ga-A1-N cladding layer of the light-emitting element portion, the ratio of Ga to A1 is changed to incline the internal refractive index of the cladding layer. Yes. However, the P-cladding layer, which is the internal structure of the light-emitting element, must have a high crystal ratio, and the p-cladding layer also affects the band gap. Therefore, continuously changing the amount of A1 (aluminum) inside the p-cladding layer is not preferable for the structure of the light-emitting element portion using a semiconductor pn junction.

[0009] The present invention solves the above-described conventional problems, and reduces loss of light emitted from the semiconductor light emitting device by changing the refractive index within a single light transmission layer covering the semiconductor light emitting device. The aim is to provide a light-emitting device that can be used!

[0010] Another object of the present invention is to provide a method for manufacturing a light-emitting device that can efficiently manufacture a light-transmitting layer whose refractive index changes inside! / Speak.

Means for solving the problem

[0011] The first aspect of the present invention is a light emitting device comprising: a semiconductor light emitting element; an electrode for energizing the semiconductor light emitting element; and a light transmitting layer covering the light emitting side of the semiconductor light emitting element. Includes nitrogen (N), silicon (Si), and oxygen (O), and in the inner part of the light transmission layer, the oxygen concentration decreases toward the semiconductor light emitting element, and the semiconductor light emitting element The nitrogen concentration increases toward

The refractive index of the light transmission layer increases as it goes toward the semiconductor light emitting element. V.

[0012] Alternatively, the present invention provides a light emitting device including a semiconductor light emitting element, an electrode for energizing the semiconductor light emitting element, and a light transmissive layer covering a light emitting side of the semiconductor light emitting element. Nitrogen (N) and silicon (Si) are included, and the relative concentration of nitrogen with respect to silicon decreases in the light transmission layer toward the semiconductor light emitting element, and the refractive index of the light transmission layer is As it goes to the semiconductor light emitting device, it becomes higher.

V.

[0013] Alternatively, the present invention provides a light-emitting device comprising a semiconductor light-emitting element, an electrode that supplies current to the semiconductor light-emitting element, and a light-transmitting layer that covers a light-emitting side of the semiconductor light-emitting element. Nitrogen (N), silicon (Si), and oxygen (O) are included, and in the inner portion of the light transmission layer, the oxygen concentration decreases toward the semiconductor light-emitting element and toward the semiconductor light-emitting element. As the concentration of nitrogen increases and the oxygen concentration decreases, the relative concentration of nitrogen with respect to silicon decreases toward the semiconductor light emitting device.

The refractive index of the light transmission layer increases as it goes toward the semiconductor light emitting element.

V.

[0014] In the above invention, it is preferable that the relative concentration of nitrogen with respect to silicon decreases toward the semiconductor light emitting device after the oxygen concentration has decreased to approximately 1% or less.

In the first aspect of the present invention, since the refractive index is changed in the light transmission layer covering the semiconductor light emitting element, it is possible to reduce the emission loss of light emitted from the semiconductor light emitting element.

[0016] A second aspect of the present invention is a light emitting device comprising: a semiconductor light emitting element; an electrode for energizing the semiconductor light emitting element; and a light transmitting layer covering the light emitting side of the semiconductor light emitting element. Is a transparent synthetic resin in which particles having a refractive index higher than that of the synthetic resin and transparent and having an average particle size of lOOnm or less are mixed, and the relative amount of the particles in the synthetic resin is Increasing toward the semiconductor light emitting device,

The light transmission layer has a refractive index that increases toward the semiconductor light emitting element. For example, the particles are titanium oxide. [0017] In the second aspect of the present invention, it is possible to change the refractive index in the light-transmitting layer made of resin formed on the surface of the semiconductor light emitting device, and to reduce the emission loss of the light emitted from the semiconductor light emitting device.

[0018] In both the first and second aspects of the present invention, since the refractive index gradient is realized in the light transmission layer formed on the surface of the semiconductor light emitting device, the internal structure of the semiconductor light emitting device can be freely designed. Can have a degree. In addition, since the refractive index in the light transmission layer can be set relatively freely, the present invention can be applied regardless of the refractive index of the semiconductor light emitting element.

In the first invention and the second invention, it is preferable that the refractive index is continuously changed in the light transmission layer. However, in the present invention, the refractive index may be changed stepwise within a single light transmission layer.

In the present invention, for example, the semiconductor light emitting element is gallium nitride (Ga—N) or a gallium nitride containing another element.

[0021] By using the semiconductor light emitting element, light having a wavelength ranging from green to blue, and further, light having a wavelength in the ultraviolet region can be emitted. However, the present invention is not limited to the case where the semiconductor light emitting element is gallium nitride. For example, Ga—P that obtains yellow-green light emission, Ga—As—P that can emit light in the wavelength range from yellow to red, red It is Ga—Al—As that can emit luminescence.

[0022] A third aspect of the present invention is a method for manufacturing a light emitting device, comprising: a semiconductor light emitting element; an electrode for energizing the semiconductor light emitting element; and a light transmission layer covering the light emitting side of the semiconductor light emitting element. ,

Forming the light transmitting layer containing nitrogen (N), silicon (Si), and oxygen (O) on the light emitting side of the semiconductor light emitting device;

As the light transmission layer is deposited from the semiconductor light emitting element side, the amount of nitrogen is gradually reduced and the amount of oxygen is gradually increased.

The light-transmitting layer having a refractive index that decreases as the semiconductor element force increases is formed.

[0023] Alternatively, the present invention provides a method for manufacturing a light-emitting device, comprising: a semiconductor light-emitting element; an electrode that supplies current to the semiconductor light-emitting element; and a light-transmitting layer that covers a light-emitting side of the semiconductor light-emitting element. Forming the light transmission layer containing nitrogen (N) and silicon (Si) on the light emitting side of the semiconductor light emitting device;

As the light transmission layer is deposited from the semiconductor light emitting element side, the relative amount of nitrogen with respect to silicon is gradually increased,

Alternatively, the present invention provides a method for manufacturing a light-emitting device, comprising: a semiconductor light-emitting element; an electrode that supplies current to the semiconductor light-emitting element; and a light-transmitting layer that covers a light-emitting side of the semiconductor light-emitting element.

As the light transmission layer is deposited from the semiconductor light emitting element side, the relative amount of nitrogen with respect to silicon is gradually increased, and then the amount of nitrogen is gradually decreased and the amount of oxygen is gradually increased.

[0025] For example, the light transmission layer is formed by chemical vapor deposition (CVD), and the supply amount of a source gas containing an element forming the light transmission layer is varied, so that the semiconductor element is separated. The light transmission layer having a low refractive index can be formed.

In the third aspect of the present invention, after the semiconductor light emitting device is manufactured,

The light transmission layer can be formed by a relatively easy process of depositing a film by the CVD method. Also,

In the case of the CVD method, it is possible to arbitrarily set the refractive index of the light transmission layer by changing the supply amount of the source gas. However, in the third aspect of the present invention, the light transmission layer can be formed by using various methods such as a sputtering method and a laser ablation method and varying the amounts of nitrogen, silicon, and oxygen.

[0027] A fourth aspect of the present invention is a method for manufacturing a light emitting device, comprising: a semiconductor light emitting element; an electrode for energizing the semiconductor light emitting element; and a light transmission layer covering the light emitting side of the semiconductor light emitting element. , A mixed fluid in which a transparent synthetic resin and a transparent particle having a higher refractive index than that of the synthetic resin and a transparent average particle diameter of ΙΟΟη m or less are supplied to the light emitting side of the semiconductor light emitting element, The relative amount of the particles in the synthetic resin is gradually reduced as the distance from the semiconductor light emitting element increases.

The synthetic resin is cured to form a light transmission layer whose refractive index gradually decreases as the distance from the semiconductor light emitting element is increased.

For example, titanium oxide is used as the particles.

[0028] In the fourth aspect of the present invention, when a mixed fluid containing a synthetic resin is supplied to the surface of a semiconductor light emitting device that has been manufactured and cured, light transmission with a refractive index gradient can be achieved in a simple manner. A layer can be formed. In addition, the refractive index in the light transmission layer can be set relatively freely by selecting the amount of particles in the synthetic resin, and further selecting the particles (selecting the refractive index of the particles).

In the present invention, it is possible to suppress the light emission loss by providing one layer of the light transmission layer on the surface of the semiconductor light emitting element. Further, the sealing layer having a low refractive index is provided on the surface of the light transmission layer. May be formed.

The invention's effect

In the light emitting device of the present invention, since the refractive index gradient is provided in the light transmission layer formed on the surface of the semiconductor light emitting element, the loss of light emission can be reduced with the structure of the semiconductor light emitting element optimized. Can be reduced.

[0031] The light emitting device manufacturing method of the present invention can form a light transmission layer having a refractive index gradient by supplying, for example, a CVD method or a resin material. It is possible to design.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is an enlarged cross-sectional view showing a light emitting device 1 according to a first embodiment of the present invention.

The light-emitting device 1 is a light-emitting diode chip, and the light-emitting device 1 is used by being housed in a receptacle having a reflector and a lead terminal.

A plurality of chip-like light emitting devices 1 are simultaneously formed on a relatively large substrate, and then diced together with the substrate and separated into individual light emitting devices 1. However, in Describes the structure of one light-emitting device 1 and its manufacturing method will be described with reference to one light-emitting device 1.

In the light emitting device 1, the semiconductor light emitting element 10 is formed on the surface of the sapphire substrate 2 by a thin film process. This semiconductor light emitting device 10 has a Ga—N (gallium nitride) buffer layer (not shown) formed thinly on the surface of the sapphire substrate 2, and an n-type contact layer 11 is formed on the buffer layer. Has been. The n-type contact layer 11 is a Ga—N layer doped with Si (silicon) and has a thickness of about 4 m. On the n-type contact layer 11, an n-type cladding layer 12 is formed in close contact. The n-type cladding layer 12 is made of Al—Ga—N, or is made of Al—Ga—N and Si-doped n-type Ga—N, and its thickness is 1. O / zm Degree.

An active layer 13 is formed in close contact with the surface of the n-type cladding layer 12. The active layer 13 is formed of n-type In—Ga—N (indium / gallium / nitrogen) or a stacked film of Si-doped n-type In—Ga—N and In—Ga—N. The total film thickness is about 400 angstroms. A p-type cladding layer 14 is formed in close contact with the surface of the active layer 13. The p-type cladding layer 14 is made of Al—Ga—N (aluminum “gallium” nitrogen), or made of Al—Ga—N and Ga—N, and has a thickness of about 0.5 m. is there. Furthermore, a contact layer 15 is formed on the surface of the p-type cladding layer 14.

[0036] The contact layer 15 is a p-type metal layer formed with a thin film thickness so as to transmit light, and is formed of, for example, a Ni'Au alloy (nickel 'gold alloy). Alternatively, the contact layer 15 is formed of ITO (indium tin oxide) which is a transparent electrode layer. This contact layer 15 is formed on the entire surface of the p-type cladding layer 14, and current is distributed from the contact layer 15 to a wide range of the semiconductor light emitting device 10.

[0037] After the layers constituting the semiconductor light emitting device 10 are formed, the layers from the n-type cladding layer 12 to the contact layer 15 are removed, and a part of the n-type contact layer 11 is exposed. An n electrode 3 is formed on the surface of the exposed portion of the n-type contact layer 11.

Further, the p-electrode 4 is formed on the surface of the contact layer 15 at a position avoiding the light emitting region. The n electrode 3 and the p electrode 4 are made of NiZAu (a nickel / gold laminate). Alternatively, by providing only the ITO contact layer 15 without providing the p-electrode 4, the light emission region is obtained. Can widen the area.

[0039] Then, a light transmission layer 20 is formed in close contact with the light emitting side surface of the semiconductor light emitting element 10 with the n electrode 3 and the p electrode 4 partially covered with a resist layer. After 20 is formed, the resist layer is removed.

The light transmission layer 20 is a transparent layer containing nitrogen (N), silicon (Si), and oxygen (O), and is formed by a chemical vapor deposition method (plasma CVD method).

[0041] In the plasma CVD method, a plurality of light emitting devices 1 having the semiconductor light emitting element 10 and the electrodes 3 and 4 are formed on a relatively large substrate 2 and the substrate 2 is brazed. Installed in the reaction chamber of the Zuma CVD system. Then, hydrogen gas (H) is charged into the reaction chamber.

2 Used as rear gas, source gas (reaction gas) silane gas (SiH), ammonia gas (

Four

NH) and nitrogen oxide gas (N 2 O) are supplied, and a light transmission layer is formed on the surface of the semiconductor light emitting device 10.

3 2

20 is deposited. Silane gas (SiH) is a source gas that supplies silicon (Si).

Four

Near gas (NH) is a source gas that supplies nitrogen (N), and nitrogen oxide gas (N 2 O) is oxygen.

3 2

(o) is a raw material gas to be supplied.

[0042] In the process of depositing the light-transmitting layer 20 on the surface of the semiconductor light emitting element 10 by plasma CVD, a valve for supplying each source gas to the reaction chamber is adjusted to adjust the reaction chamber of each source gas. To control the flow rate to. Alternatively, the partial pressure of the material valve supplied to the reaction chamber is controlled. The variable control of the supply ratio of the raw material gas may be changed stepwise or continuously.

[0043] Table 1 below shows an example in which the supply ratio of the raw material gas is changed stepwise in the order of steps a, b, c, d,. In the manufacturing examples shown in Table 1, the numbers in the table indicate the flow rate, and the unit is “sccm (standard cc / min)”. However, in Table 1, it can also be understood that the supply ratio of each raw material gas is expressed as a relative amount with silane gas (SiH) as “1”.

Four

A light transmission layer 20 is formed on the surface of the semiconductor light emitting element 10 by changing the supply ratio of the source gas in order from step a to step. However, during steps a to c, silane gas (SiH 2) and ammonia gas (NH 2) are supplied without supplying nitrogen oxide gas (N 2 O).

2 4 3

Start supplying nitrogen oxide gas (N 2 O).

2

[0045] In steps a to d, as the film formation of the light transmission layer 20 proceeds, silane gas Increase the amount of ammonia gas (NH 3) supplied to (SiH 2) step by step. Process a

4 3

The light-transmitting layer 20 formed between step c and step c is a silicon nitride film (Si—N). The light transmitting layer 20 formed when reaching step d is a force that is silicon oxynitride (Si—O—N). The oxygen concentration at this point is 1% or less. In the light transmission layer 20 formed in steps a to d, the relative concentration of N with respect to Si decreases toward the interface with the semiconductor light emitting device 10, and conversely with the semiconductor light emitting device 10. The relative concentration of N with respect to Si increases as the interface force increases.

[0046] Here, the concentration of each element in the light transmission layer 20 is a deviation of the amount of at%, the amount of mol, or the mass ratio.

[0047] As shown in Table 1, the refractive index of the light transmission layer 20 formed between steps a and d is approximately 2.4 near the boundary surface with the semiconductor light emitting element 10, and the step d At this point, the refractive index is about 1.98. The refractive index in this specification means an absolute refractive index when light having a wavelength of 680 nm is incident.

[0048] After the step d, the film formation of the light transmission layer 20 is continuously continued. In steps d to i, the supply amount of silane gas (SiH) is fixed and the film formation proceeds. Therefore

Four

Reduce the supply amount of nitrogen gas (NH) gradually and reduce the supply amount of nitrogen oxide gas (N 2 O).

3 2

Gradually increase. Then, the supply amount of ammonia gas (NH 3) is set to zero at the completion of step i, that is, when the light transmission layer 20 is formed.

Three

[0049] The internal structure of the light transmission layer 20 formed in steps d to h is substantially silicon oxynitride (Si—O—N). In the light transmission layer 20 formed during this step, As the distance from the semiconductor light emitting element 10 increases, the concentration of oxygen (O) increases and the concentration of nitrogen (N) decreases. Conversely, the oxygen (O) concentration decreases and the nitrogen (N) concentration increases toward the semiconductor light emitting element 10. When the film formation shown in step i is completed, the surface of the light transmission layer 20 has a configuration close to silicon oxide (SiO or SiO 2).

2

[0050] As shown in Table 1, in steps d to i, in silicon oxynitride (Si-0-N), nitrogen (N) changes to oxygen (O) as the distance from semiconductor light-emitting element 10 increases. It is a configuration that will be replaced. Therefore, the internal refractive index gradually decreases according to the directional force on the surface of the light transmission layer 20, and the refractive index is approximately 1.53 on the surface of the light transmission layer 20. [0051] The light transmission layer 20 formed by the above plasma CVD method has a refractive index of approximately 2.4 at the interface with the semiconductor light emitting device 10, and the p-type cladding layer 14 of the semiconductor light emitting device 10 or Can have a refractive index very close to that of the contact layer 15 (these refractive indices are approximately 2.5), or the refractive index difference can be almost eliminated. Further, the refractive index of the surface of the light transmission layer 20 can be set to approximately 1.53.

[0052] When the contact layer 15 is made of ITO, the refractive index of the contact layer 15 is approximately 2.0, and the refractive index of the light transmission layer 20 is 2.4 at the contact interface with ITO. Become. In this case, light that has passed through the p-type cladding layer 14 having a refractive index of approximately 2.5 passes through ITO and is incident on the light transmission layer 20. At this time, light is incident on the light transmissive layer 20 having a high refractive index from ITO having a low refractive index, and therefore, the total reflection angle at the interface between the ITO and the light transmissive layer 20 is generated according to Snell's law. However, the loss of the emitted light at the interface is slight.

Similar to the third embodiment shown in FIG. 3, the chip-like light emitting device 1 shown in FIG. 1 is housed in a package that also serves as a reflector, and is provided in one of the packages provided in the knocker. The lead terminal and the n electrode 3 are connected by wire bonding, and the other lead terminal and the p electrode 4 are connected by wire bonding. Further, a sealing layer is formed on the surface of the chip-like light emitting device 1, and the light emitting device 1 is sealed so that it does not touch the outside air inside the socket. The sealing layer is formed of a transparent synthetic resin material, for example, epoxy resin. Since the refractive index of the epoxy resin is about 1.5, the difference in refractive index at the interface between the epoxy resin sealing layer and the surface of the light transmitting layer 20 can be almost eliminated.

[0054] Alternatively, the sealing layer may be formed of PAA (polyallylamine). This resin material is not easily discolored by light energy or heat. The refractive index is about 1.48. Therefore, even when PAA is used for the sealing layer, the difference in refractive index at the interface between the sealing layer and the light transmission layer 20 is reduced.

In the light emitting device 1, a positive potential is applied to the p electrode 4, and a forward current is applied to the pn junction semiconductor light emitting element 10. Free electrons, which are negative charges in the n-type cladding layer, and free holes in the p-type cladding layer 14 recombine in the active layer 13 and emit light with the energy at that time. The wavelength of light emitted from the semiconductor light-emitting element 10 mainly composed of Ga-N is 530 nm or less, and can emit light up to the green power, the blue band and the ultraviolet band. [0056] There is almost no difference in refractive index at the interface between the semiconductor light emitting element 10 and the light transmission layer 20. Also, when the contact layer 15 is made of ITO, the refractive index is low! The ITO force is also high. Since light is incident on the fluorescent transmission layer 20, total reflection at the interface between the semiconductor light emitting element 10 and the light transmission layer 20 can be reduced, and light loss can be suppressed. Furthermore, since there is almost no difference in refractive index between the light transmission layer 20 and the sealing layer, it is possible to reduce the total light reflection and reduce the loss of light emission.

[0057] Next, the light emitting device 1 is housed in the package, and a sample in which an epoxy resin sealing layer is provided on the surface of the light transmission layer 20 is manufactured. A sample in which only the epoxy resin sealing layer was provided without the overlayer 20 was produced. In forming the light transmissive layer 20, the source gas is changed stepwise from step a to step i shown in Table 1 by the plasma CVD method (source gas supply rate is sccm), and the plasma excitation frequency is set to 13. The substrate temperature was set to 56 MHz and the substrate temperature was set to 200 ° C. The contact layer 15 is made of ITO.

[0058] Table 2 shows the result of measuring the luminous flux of the emitted light when each sample was caused to emit light. In Table 2, the sample numbers are indicated as “LED A”, “LED B”, “LED C”. Each numbered sample uses the same light emitting device 1, but the supply current value (mA) between the electrodes 3 and 4 is different. Table 2 shows the measurement results of the luminous flux (lm: lumen) when the light transmission layer 20 and the sealing layer are formed on each sample and the measurement results of the luminous flux (lm: lumen) when only the sealing layer is used. Show me!

[0059] [Table 1] Table 1

[0060] [Table 2] Table 2

Next, in the light emitting device 1 shown in FIG. 1, when the contact layer 15 is made of ITO, the steps a to 1 shown in Table 1 are performed when the light transmission layer 20 is formed on the surface thereof. The process c may be deleted, and the film formation process may be performed in the process starting with the process power of d. That is, using hydrogen gas (H) as a carrier gas in the reaction chamber of the plasma CVD apparatus,

2

Silane gas (SiH 3), ammonia gas (NH 2), and nitrogen oxide gas (N 2 O) as reaction gases

Supply 4 3 2 Then, the amount of silane gas (SiH) was fixed and the film formation progressed.

Four

Therefore, increase the supply amount of nitrogen oxide gas (N 2 O) and increase the amount of ammonia gas (NH 2).

2 3 Reduce supply.

As a result, the light-transmitting layer 21 is substantially silicon oxynitride (Si-0-N), and the light-transmitting layer 21 becomes oxygen (O as the interface force with the contact layer 15 that is ITO increases. ) Concentration increases and nitrogen (N) concentration decreases. The light transmissive layer 21 has a refractive index of approximately 1.98 at the interface with the contact layer 15, and the refractive index difference between the light transmitting layer 21 and the contact layer 15 formed of ITO having a refractive index of approximately 2.0 is small or different. Almost disappears. Further, the surface of the light transmission layer 21 has a structure close to silicon oxide (SiO or SiO 2), and its refractive index is approximately 1.53.

2

[0063] As still another modification of the light-emitting device 1 shown in FIG. 1, the light transmission layer 20 is formed in the processes indicated by a to c shown in Table 1, and the film formation is completed in the process c. Alternatively, film formation may be performed in steps a to d and film formation may be completed in step d. The light-transmitting layer 20 formed in steps a to c is substantially a silicon nitride film (Si—N), has a refractive index of 2.4 at the interface with the semiconductor light emitting device 10, and has a refractive index on the light emitting side surface. Is 2.1. The light-transmitting layer 10 formed in steps a to d is substantially a silicon nitride film (Si—N). Only the surface formed in step d is silicon oxynitride. (Si-O-N), and the oxygen concentration on this surface is less than 1%. The light transmitting layer 20 formed in steps a to d has a refractive index of 2.4 at the interface with the semiconductor light emitting element 10 and a refractive index of 1.98 on the light emitting side surface.

[0064] As described above, even when the light-transmitting layer 20 is formed on the surface of the semiconductor light-emitting element 10 in the steps a to c or the light-transmitting layer 20 is formed in the steps a to d, the semiconductor light emitting device The difference in refractive index at the interface between the element 10 and the light transmission layer 20 can be reduced, and the refractive index of the light transmission side surface of the light transmission layer 20 can be as low as 2.1 or 1.98.

FIG. 2 is an enlarged sectional view showing a light emitting device 31 according to the second embodiment of the present invention. In the second embodiment shown in FIG. 2, the same components as those of the light emitting device 1 of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof is omitted.

[0066] As in the first embodiment, the light-emitting device 31 has a chip shape and is housed in a package that also serves as a reflector.

The basic structure of the light emitting device 31 is the same as that of the first embodiment, and the semiconductor light emitting element 10 is provided on the sapphire substrate 2. However, the light emitting device 31 is used in the upside down direction with respect to the light emitting device 1 of the first embodiment, the sapphire substrate 2 is directed to the light emitting side, and the contact layer 15 is directed to the package substrate 32. Yes. A lead layer 33 is provided on the surface of the package substrate 32, and a p-electrode 4 is connected to the lead layer 33. The n-electrode 3 is connected to another lead layer on the surface of the knock substrate 32 by wire bonding.

[0068] A light transmission layer 20 is formed on the surface of the sapphire substrate 2 facing the light emitting side. This light transmission layer 20 is formed by the plasma CVD method as in the first embodiment shown in FIG. 1. From the sapphire substrate 2 side, light transmission is performed in steps a to i shown in Table 1. Layer 20 is deposited. This light transmission layer 20 has a refractive index of 2.4 at the interface with the sapphire substrate 3 and a refractive index of the light emitting side surface of 1.53.

[0069] Light emitted from the semiconductor light emitting element 10 passes through the sapphire substrate 2, passes through the light transmission layer 20, and then enters a sealing layer provided on the surface thereof. The refractive index of the sapphire substrate 2 is about 1.8, and the light emitted from the semiconductor light emitting element 10 enters the light transmission layer 20 having a high refractive index from the sapphire substrate 2 having a low refractive index. Therefore, Snell's law As a result, the total reflection angle at the interface between the sapphire substrate 2 and the light transmission layer 20 does not occur, and it is possible to suppress a decrease in light incident efficiency at this interface. Further, the refractive index on the light emitting side surface of the light transmission layer 20 can be lowered to 1.53.

As shown in FIG. 2, when the light transmission layer 20 is formed on the surface of the sapphire substrate 2, the steps a to c shown in Table 1 are omitted, and the process force of d is also started. The film formation may be completed in step i. Alternatively, the process force of e may start the film formation, or the process force of f may start the film formation and complete the film formation in the process i. In this case, the interface with the sapphire substrate 3 [Koo! / The refractive index of the light transmitting layer 20 is 1. 98 or ί or 1. 89! / ヽ ί or 1. 81 [can be used to suppress total reflection at the interface with the safing substrate 2 become. The substrate is not limited to the sapphire substrate, but may be made of other materials as long as it can transmit light.

FIG. 3 is a cross-sectional view showing a light emitting device 101 according to the third embodiment of the present invention.

The light-emitting device 101 is a device in which a light-emitting device 1 a having the same structure as the chip-shaped light-emitting device 1 shown in FIG. 1 is housed, sealed, and packaged. However, the light emitting device having the structure shown in FIG. 2 may be housed and sealed.

[0072] The chip-like light emitting device la housed in the light emitting device 101 is obtained by removing the light transmission layer 20 from the light emitting device 1 shown in FIG. 1, and other configurations are shown in FIG. It is the same as the one. The contact layer 15 is made of ITO.

In the light emitting device 101 shown in FIG. 3, a heat radiating member 103 is provided on the surface of the knock substrate 102. The heat radiating member 103 is made of a material having high thermal conductivity such as aluminum or copper. The chip-shaped light emitting device la is installed and bonded to the surface of the heat radiating member 103.

The heat radiating member 103 and the light emitting device la are covered with a package material 104. The package material 104 has high heat resistance and is an electrically insulating material, and is made of, for example, aluminum nitride (Al—N). As for the surface force of the package substrate 102, a pair of lead electrodes 105 and 106 are formed inside the package material 104. One lead electrode 105 and n electrode 3 of light emitting device la are connected by wire bonding 107, and the other lead electrode 106 and p electrode 4 of light emitting device la are connected by wire bonding 108. [0075] The anode / cage material 104 also serves as a reflector, and its surface is a reflecting surface 104a. The reflecting surface 104a is formed so that its opening area gradually increases in the light emitting direction. Yes.

Then, a light transmission layer 120 covering the semiconductor light emitting element 10 of the light emitting device la is formed on the reflection surface 104a. The light transmission layer 120 is formed by mixing particles in a transparent synthetic resin material. In this embodiment, polyallylamine (PAA) is used as the synthetic resin material. It is preferable to use a material that has heat resistance and is not easily discolored by light energy and heat. The refractive index of PAA when cured is about 1.48. However, epoxy resin can also be used as a synthetic resin material.

[0077] The particles mixed into the PAA are transparent and have a higher refractive index than the synthetic resin material, and the average particle diameter is smaller than the wavelength of light emitted from the semiconductor light emitting device 10, and the average The particle size is preferably 1 OO nm or less, more preferably the average particle size is 30 nm or less and 5 nm or more. In the third embodiment, titanium oxide (TiO 2) having an average particle diameter of 20 nm is used as the particles. The refractive index of titanium oxide is 2.5-2.

2

However, the particles are not limited to titanium oxide, and other materials can be used as long as they have a transparent and high refractive index with a small average particle diameter. For example, aluminum sapphire can also be used.

In the light transmission layer 120, the relative amount of titanium oxide particles with respect to PAA, which is a synthetic resin material, gradually decreases as the distance from the semiconductor light emitting element 10 increases. Here, the relative amount means the ratio of wt% between the synthetic resin material and the particles. Further, the relative amount of particles in the synthetic resin material may continuously decrease as the distance from the semiconductor light emitting element 10 increases, and the relative amount changes so as to decrease stepwise. Moyo.

[0079] The light transmission layer 120 is formed by the following steps.

When forming the light transmission layer 120, a supply device 200 shown in FIG. 4 is used. In the first material layer 201 of the supply device 200, a mixed fluid in which titanium oxide is mixed with PAA is stored. In this mixed fluid, titanium oxide particles account for 55 wt%, and the rest is PAA before hardening (100% overall). The second material layer 202 contains 100% pre-cured PAA that does not contain titanium oxide particles!

[0080] The flow rate of the mixed fluid in the first material layer 201 is controlled by the first valve 203 and mixed. The flow rate of the PAA in the second material layer 202 supplied to the compound machine 205 is controlled by the second valve 204 and supplied to the mixer 205. The mixer 205 has an extrusion screw inside, and the mixed fluid and PAA are mixed and supplied to the surface of the semiconductor light emitting device 10.

In the example shown in Table 3 below, the opening degree of the first valve 203 and the opening degree of the second valve 204 are controlled to change stepwise. The opening degree is controlled in the order of process, mouth, throat,. In the process of starting to form the light transmission layer 120, the opening force of the first valve 203 is 100% and the opening of the second valve 204 is 0%. Thereafter, as the mixed fluid is supplied onto the semiconductor light emitting element 10, the opening degree of the first valve 203 is gradually reduced and the opening degree of the second valve 204 is gradually increased. Note that at least one of the opening degree of the first knob 203 and the opening degree of the second valve 204 may be adjusted so as to continuously change.

[0082] By adjusting the valve opening degree shown in Table 3, as the fluid is supplied to the surface of the semiconductor light emitting device 10, the relative supply amount of titanium oxide particles to PAA gradually decreases. . After supplying the fluids in the order of steps 1 to 5 in Table 1, PAA, which is a thermosetting synthetic resin material, is cured by the annealing process, and the formation of the light transmission layer 120 is completed.

[0083] The light-transmitting layer 120 after curing is an interface in close contact with the semiconductor light-emitting element 10 of the light-emitting device la, and the titanium oxide particles occupy approximately 55 wt%. The refractive index of layer 120 is approximately 2.5. In the light transmission layer 120, the amount of titanium oxide decreases as the distance from the semiconductor light emitting element 10 increases. As a result, the refractive index gradually decreases as the distance from the semiconductor light emitting element 10 increases. Near the surface of the light transmission layer 120, PAA is formed at approximately 100 wt%, and the refractive index at the surface is approximately 1.48. FIG. 5 shows the relationship between the refractive index and the ratio (wt%) of titanium oxide in the light-transmitting layer 120 formed by the process or step.

Table 4 shows the evaluation results of the light emitting device 101 having the structure shown in FIG. In Table 4, the sample number of the light emitting device 101 is indicated by “LED F”, “LED G”, “LED H”. Each of these samples is a light emitting device having the same structure having the light transmission layer 120 formed in the process of Table 3. When the supply current value (mA) is changed for each sample using 101 and the light-transmitting layer 120 instead of the light-transmitting layer 120 and the surface of the semiconductor light-emitting element 10 provided with an epoxy resin sealing layer The evaluation results are shown. Table 4 shows the luminous flux (lm: lumen) when the light transmission layer 120 is formed on each sample, and the case where an epoxy resin sealing layer is provided on the surface of the semiconductor light emitting device 10 instead of the light transmission layer 120. The measurement results of the luminous flux (lm: lumen) are shown.

[0085] [Table 3] Table 3

[0086] [Table 4] Table 4

In the present invention, the light transmission layer 20 or 21 in the embodiment shown in FIG. 1 and FIG. 2 and the light transmission layer 120 shown in FIG. The light transmission layer 120 may be formed on the substrate.

Brief Description of Drawings FIG. 1 shows a first embodiment of the present invention, and is an enlarged cross-sectional view showing a chip-like light emitting device;

FIG. 2 shows a second embodiment of the present invention, and is an enlarged sectional view showing a chip-like light emitting device;

FIG. 3 is an enlarged cross-sectional view showing a third embodiment of the present invention, showing a light emitting device that has been subjected to observation / cage;

FIG. 4 is an explanatory view showing a fluid supply device for forming a light transmission layer of the light emitting device of the third embodiment;

FIG. 5 is a diagram showing the relationship between the amount of titanium oxide and the refractive index of the light transmission layer provided in the light emitting device of the third embodiment;

Explanation of symbols

[0088] 1, 31 light emitting device

2 Sapphire substrate

3, 4 electrodes

10 Semiconductor light emitting devices

11 n-type contact layer

12 n-type cladding, layer

13 Active layer

14 p-type cladding layer

15 Contact layer

20 Light transmission layer

101 light emitting device

102 Package substrate

103 Heat dissipation member

104 Package material

105, 106 Lead electrode

120 Light transmission layer

200 feeder

Claims

The scope of the claims

[1] In a light-emitting device having a semiconductor light-emitting element, an electrode for energizing the semiconductor light-emitting element, and a light transmission layer covering a light-emitting side of the semiconductor light-emitting element,

The light transmissive layer includes nitrogen (N), silicon (Si), and oxygen (O), and the oxygen concentration decreases toward the semiconductor light emitting element inside the light transmissive layer. Nitrogen concentration increases toward the semiconductor light emitting device,

The light-emitting device, wherein a refractive index of the light-transmitting layer increases as it goes toward the semiconductor light-emitting element.

[2] In a light-emitting device having a semiconductor light-emitting element, an electrode for energizing the semiconductor light-emitting element, and a light transmission layer covering a light-emitting side of the semiconductor light-emitting element,

The light transmission layer includes nitrogen (N) and silicon (Si), and a relative concentration of nitrogen with respect to silicon decreases in the light transmission layer toward the semiconductor light emitting element. A light emitting device characterized in that the refractive index of the layer increases as it goes toward the semiconductor light emitting element.

[3] In a light-emitting device having a semiconductor light-emitting element, an electrode for energizing the semiconductor light-emitting element, and a light transmission layer covering a light-emitting side of the semiconductor light-emitting element,

The light transmissive layer includes nitrogen (N), silicon (Si), and oxygen (O), and the oxygen concentration decreases toward the semiconductor light emitting element inside the light transmissive layer. The concentration of nitrogen increases toward the semiconductor light emitting element, and after the oxygen concentration decreases, the relative concentration of nitrogen to silicon decreases toward the semiconductor light emitting element.

[4] In a light-emitting device having a semiconductor light-emitting element, an electrode for energizing the semiconductor light-emitting element, and a light transmission layer covering the light-emitting side of the semiconductor light-emitting element.

The light transmission layer is a transparent synthetic resin in which particles having a refractive index higher than that of the synthetic resin and transparent and having an average particle size of lOOnm or less are mixed. A light emitting device characterized in that a relative amount of particles increases toward the semiconductor light emitting element, and a refractive index of the light transmission layer increases toward the semiconductor light emitting element.

5. The light emitting device according to claim 4, wherein the particles are titanium oxide.

6. The light emitting device according to claim 1, wherein the refractive index continuously changes in the light transmission layer.

7. The light-emitting device according to claim 1, wherein the semiconductor light-emitting element is gallium nitride (Ga—N) or another element contained in the gallium nitride.

[8] In a method for manufacturing a light-emitting device, comprising: a semiconductor light-emitting element; an electrode that supplies current to the semiconductor light-emitting element; and a light-transmitting layer that covers a light-emitting side of the semiconductor light-emitting element.

The method of manufacturing a light emitting device, comprising forming the light transmission layer having a refractive index that decreases as the semiconductor element force increases.

[9] In a method for manufacturing a light-emitting device, comprising: a semiconductor light-emitting element; an electrode that supplies current to the semiconductor light-emitting element; and a light-transmitting layer that covers a light-emitting side of the semiconductor light-emitting element.

Forming the light transmission layer containing nitrogen (N) and silicon (Si) on the light emitting side of the semiconductor light emitting device;

[10] In a method for manufacturing a light-emitting device, comprising: a semiconductor light-emitting element; an electrode that supplies current to the semiconductor light-emitting element; and a light-transmitting layer that covers a light-emitting side of the semiconductor light-emitting element.

Forming the light transmitting layer containing nitrogen (N), silicon (Si), and oxygen (O) on the light emitting side of the semiconductor light emitting device; As the light transmission layer is deposited from the semiconductor light emitting element side, the relative amount of nitrogen with respect to silicon is gradually increased, and then the amount of nitrogen is gradually decreased and the amount of oxygen is gradually increased.

[11] The light transmissive layer is formed by chemical vapor deposition (CVD), and the supply amount of a source gas containing an element that forms the light transmissive layer is varied, so that it is separated from the semiconductor element. 9. The method for manufacturing a light emitting device according to claim 8, wherein the light transmission layer having a low refractive index is formed.

[12] In a method for manufacturing a light-emitting device, comprising: a semiconductor light-emitting element; an electrode that supplies current to the semiconductor light-emitting element; and a light-transmitting layer that covers a light-emitting side of the semiconductor light-emitting element.

A mixed fluid in which a transparent synthetic resin and a transparent particle having a refractive index higher than that of the synthetic resin and transparent and having an average particle diameter of mηm or less are supplied to the light emitting side of the semiconductor light emitting element. The relative amount of the particles in the synthetic resin is gradually reduced according to the distance from the semiconductor light emitting element,

A method of manufacturing a light emitting device, comprising: curing the synthetic resin to form a light transmission layer having a refractive index that gradually decreases as the distance from the semiconductor light emitting element is increased.

13. The method for manufacturing a light emitting device according to claim 12, wherein titanium oxide is used as the particles.