KR20110021565A - Method of fabricating light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device manufacturing method is provided to easily separate a growth substrate using an unfilled part by forming the unfilled part on the semiconductor layer formed on the growth substrate. CONSTITUTION: A substrate(101) equipped with a first semiconductor layer(102) and a metallic material layer(103) is loaded into a first chamber. A second semiconductor layer(104) is formed on the first semiconductor layer and the metallic material layer in the first chamber. An unfilled part(102a) is formed on a portion of the first semiconductor layer and is lower than the metallic material layer.

Description

Light emitting device manufacturing method {METHOD OF FABRICATING LIGHT EMITTING DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a light emitting device, and in particular, to form a cavity in a semiconductor layer formed on a growth substrate, while preventing the contamination of the growth chamber of the compound semiconductor layer by reaction by-products resulting from the formation of a compound of good quality. A light emitting device manufacturing method capable of growing a semiconductor layer.

BACKGROUND OF THE INVENTION Light emitting diodes (hereinafter referred to as LEDs) using gallium nitride (GaN) -based semiconductors have been used in various devices such as signal signals and backlights of liquid crystal panels. It is known that the luminous efficiency of LED is influenced by dislocation density and defect of a crystal. Crystal growth of GaN-based semiconductors is performed on dissimilar substrates such as sapphire, but it is considered that lattice mismatch and mismatch of thermal expansion coefficients occur between the GaN layer and the substrate, leading to an increase in high potential density and defects.

Here, it is preferable to perform crystal growth of a GaN type semiconductor on the board | substrate of the same material, such as a GaN substrate. On the other hand, GaN is difficult to form a GaN melt due to the high dissociation rate of nitrogen, etc., making it difficult to manufacture a GaN substrate. In order to peel GaN bulk crystals grown for GaN substrates as GaN substrates, mechanical polishing and laser peeling are used, but it is very difficult to reproduce a GaN substrate having a practical size. In particular, laser peeling requires a large amount of time, causing a cost increase of the GaN substrate.

As described above, since the manufacture of GaN substrates is very difficult and expensive, semiconductor devices such as LEDs and laser diodes are often manufactured by growing GaN layers on different substrates such as sapphire. However, the increase in the high potential density and defects described above hinders the improvement of the light emitting performance of the LED. In addition, the sapphire substrate has a lower thermal conductivity than the GaN substrate and lowers the heat radiation of the device. This causes the long life of the LED or laser diode to be prevented.

In order to solve the problem of sapphire, the GaN layer is grown using these dissimilar substrates as a growth substrate, and then a secondary substrate is attached, and a GaN layer is formed at the interface between the sapphire, which is a growth substrate, and the GaN layer, using an excimer laser. Laser lift-off methods have been developed to locally decompose to remove sapphire.

However, as described above, peeling of the growth substrate using a laser requires a large amount of time, thereby increasing the manufacturing cost of the light emitting element.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a light emitting device manufacturing method for forming a cavity in a semiconductor layer formed on a growth substrate so that a growth substrate of dissimilar material can be easily peeled off without using a laser.

The technical problem to be solved by the present invention is a light emitting device manufacturing method which can prevent the crystal quality of the compound semiconductor layer formed on the semiconductor layer is reduced by the reaction by-products generated when forming a cavity in the semiconductor layer. To provide.

One embodiment of the present invention provides a light emitting device manufacturing method. The method loads a substrate having a first semiconductor layer and a metallic material layer formed in a pattern shape on the first semiconductor layer into a first chamber, and within the first chamber on the first semiconductor layer and the metallic material. While forming a second semiconductor layer on the material layer, a cavity is formed in the first semiconductor layer below the metallic material layer, and the substrate having the second semiconductor layer is removed from the first chamber. Transferring to the second chamber, and forming a compound semiconductor layer on the second semiconductor layer in the second chamber.

Also, transferring the substrate is performed without vacuum breaking. That is, when transferring the substrate, the substrate is not exposed to the atmosphere, and thus the compound semiconductor layer can be grown on the second semiconductor layer without having to clean the surface of the second semiconductor layer.

On the other hand, the metallic material layer is formed on the first semiconductor layer in a stripe shape at regular intervals and widths, and the second semiconductor layer covers the metallic material layer. To this end, the second semiconductor layer is formed at least 1/2 times the width of the metallic material layer.

In addition, the metallic material layer may have an oxide film, and the oxide film may form a mask for the first semiconductor layer.

In addition, the metallic material layer may be formed to a thickness in which a plurality of holes are formed through the first semiconductor layer and the second semiconductor layer.

On the other hand, the first semiconductor layer and the second semiconductor layer are formed using the same or different compound semiconductor material, and the metallic material layer has a higher melting point than the heating temperature at the time of forming the second semiconductor layer. It is preferable to form using a metallic material.

In addition, the metallic material layer has an oxide film, the oxide film forms a mask for the first semiconductor layer, and forms a plurality of holes through the first semiconductor layer and the second semiconductor layer. And forming the second semiconductor layer by an organometallic vapor phase growth method, reacting the first semiconductor layer below the portion where the metallic material layer is formed with the metallic material layer and oxygen to form the plurality of holes. Can be evaporated from to form the cavity.

On the other hand, the metallic material layer is tantalum, the film thickness is 5nm to 100nm, after the formation on the first semiconductor layer, the surface of the tantalum may be wrapped with tantalum oxide.

The substrate may be a sapphire substrate or a silicon-based substrate.

The forming of the compound semiconductor layer may include forming a first compound semiconductor layer, forming an active layer on the first compound semiconductor layer, and forming a second compound semiconductor layer on the active layer. .

In addition, a second substrate may be attached onto the second compound semiconductor layer, and the substrate may be peeled off using the cavity formed in the first semiconductor layer.

According to the present invention, by forming a cavity in the semiconductor layer formed on the growth substrate, the growth substrate can be easily peeled off using the cavity. In addition, even if the chamber is contaminated by reaction by-products generated when the cavity is formed, a compound semiconductor layer of good quality can be grown by separating the chamber for forming the cavity and the chamber for growing the compound semiconductor layer.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on attached drawing. In addition, embodiment described below is only one form of this invention, respectively, and this invention is not limited to this embodiment.

(Embodiment 1)

1 is a view showing an outline of a light emitting element manufacturing method according to the first embodiment, and FIG. 2 is a schematic view of a light emitting element manufacturing apparatus used in the light emitting element manufacturing method. (A) is sectional drawing which shows the process of forming a 1st GaN layer and a metal material layer, (B) is sectional drawing which shows the formation process of a 2nd GaN layer, and a cavity, (C) is a compound semiconductor layer, It is sectional drawing which shows the process of forming.

In FIG. 1A, 101 is a sapphire (Al ₂ O ₃ ) substrate. First, a first GaN layer 102 having a thickness of about 2 μm is formed on the sapphire substrate 101. The thickness of this first GaN layer is an example and is not limited.

Next, the Ta layer (metallic material layer) 103 having a thickness of about 50 nm is stripe-shaped at 5 μm width and 5 μm intervals by using EB (Electron Beam) deposition and lift-off on the first GaN layer 102. Form. The shape, thickness, width, and spacing of this Ta layer 103 are examples and are not limited.

Next, in FIG. 1B, the substrate 101 having the first GaN layer 102 and the Ta layer 103 is loaded into the first chamber (10 in FIG. 2), and the first GaN layer ( On the 102 and the Ta layer 103, the second GaN layer 104 is formed using an organometallic vapor phase growth method (hereinafter referred to as MOCVD method). FIG. 1B illustrates a state in which the second GaN layer 104 is formed. In this case, N and Ta of the GaN layer combine to form TaN, which becomes a different material, and the N rises in a darker gas phase. TaN becomes unstable at 900 degreeC or more, vaporizes at 1000 degreeC or more, and a hole deepens with the vaporization, and the cavity 102a is formed. N of GaN becomes TaN, but Ga remains. Since Ga is the same as Ga deposited during gas phase growth, it is used as a raw material.

Meanwhile, the second GaN layer 104 may be formed at least 1/2 of the Ta layer 103. Meanwhile, an upper limit of the second GaN layer 104 is not particularly limited, but may be less than 1000 μm.

When the formation of the second GaN layer 104 is advanced by the MOCVD method, as shown in the figure, etching of the first GaN layer 102 under the Ta layer 103 proceeds and the cavity 102a is carried out. The formation region of is also enlarged almost on the sapphire substrate 101. In addition, since the growth of the first GaN layer 102 also proceeds with the growth of the second GaN layer 104, the substrate surface is planarized as shown in FIG. 1.

As will be described in detail later, reaction by-products are generated by the combination of Ta and N during growth of the second GaN layer 104. Such reaction by-products may contaminate the first chamber 10, and when the compound semiconductor layer is grown in the first chamber 10, the crystal quality of the compound semiconductor layer may be degraded. Therefore, the compound semiconductor layer is performed in the second chamber 20 spatially separated from the first chamber 10.

That is, after the growth of the second GaN layer 104 is completed, the substrate 101 is transferred from the first chamber 10 to the second chamber (20 in FIG. 2). The first chamber 10 and the second chamber 20 are connected through a communication path 30. A shutter 13 may be installed between the first chamber 10 and the communication path 30 to block contaminants in the first chamber from moving to the second chamber 20, and the second chamber 20 may also be provided. And the shutter 23 may be installed between the communication path 30. Although the shutters are respectively provided between the chambers 10 and 20 and the communication path 30, only one shutter may be installed in the communication path.

In each chamber, there are pedestals 11 and 21 for supporting the substrate 101, and heaters (not shown) for heating the substrate 101 are provided in the pedestals 11 and 21. Although not shown, source lines for supplying source gas and carrier gas to each of the chambers 10 and 20 and exhaust lines for vacuum evacuation are connected.

Since the first chamber 10 and the second chamber 20 are connected through the communication path 30, the substrate 101 is moved from the first chamber 10 to the second chamber 20 without vacuum breaking. Can be transferred.

Next, in FIG. 1C, the first compound semiconductor layer 201, the active layer 202, and the second compound semiconductor layer () are formed on the second GaN layer 104 in the second chamber 20. 203 is formed.

The compound semiconductor layers 201, 202, and 203 may be formed using an organometallic vapor phase growth method, like the second GaN layer 104, and may be a gallium nitride-based compound semiconductor layer.

Since the compound semiconductor layers are formed in the second chamber 20 separated from the first chamber, it is possible to prevent degradation of crystal quality of the compound semiconductor layers by reaction by-products generated when the cavity 102a is formed. . Furthermore, since the substrate 101 can be transferred from the first chamber 10 to the second chamber 20 without breaking the vacuum, the second GaN layer 104 and the compound semiconductor layers 201, 202, and 203 may be transferred. It can be grown in an in-situ process.

In the first embodiment, since the cavity 102a is formed in the first GaN layer 102 on the substrate 101, the substrate 101 can be easily peeled off using the cavity 102a.

When the sapphire substrate 101 is peeled off, for example, a laser lift off method may be used, or a polishing method or wet etching may be used. In addition, the sapphire substrate 101 may be twisted and peeled from the first GaN layer 102. This embodiment does not specifically limit the method of peeling the sapphire substrate 101. FIG.

(Example 1)

Next, a specific example of the formation of the cavity 102a will be described below. In the first embodiment, a process of forming the second GaN layer 104 on the substrate 101 using the MOCVD apparatus will be described. An example in which the growth temperature is set to 1045 ° C. and crystal growth is performed for 5 hours while flowing TMGa at a flow rate of 20 μmol / min using trimethyl gallium (hereinafter referred to as TMGa) as the source gas. In the first embodiment, a Ta layer 103 having a thickness of 50 nm is formed on the first GaN layer 102 in a stripe shape.

The SEM cross-sectional photograph of the sample by which the formation of the 2nd GaN layer 104 was completed on the said conditions is shown in FIG. As is apparent from this figure, a cavity 102a is formed in the first GaN layer 102 under the formation region of the Ta layer 103. 4 shows the results of analysis using an energy dispersive X-ray spectrometer (hereinafter referred to as EDX) for the enlarged region shown in the figure including the cavity 102a.

As shown in the spectral diagram by EDX in FIG. 4, GaN of the first GaN layer 102 and Al and O of the sapphire substrate 101 were observed, and Ta was hardly observed. 5 (B) to (D) As shown in the EDX diagram, Ga of the first GaN layer 102 and Al and O of the sapphire substrate 101 were observed, but Ta was not observed.

In Example 1, it was observed that the hole 103a was formed in the Ta layer 103 during the formation of the second GaN layer 104. The analysis result of the hole 103a formed in this Ta layer 103 is further demonstrated in FIG. 6 and FIG. In addition, the analysis result shown in FIG. 6 and FIG. 7 is the result of analyzing by EDX, stopping the formation process of the 2nd GaN layer 104 using the MOCVD apparatus in the middle.

In FIG. 6, (A) is a SEM cross-sectional photograph of a sample, (B) is a SEM surface photograph of a sample. In FIG. 7, (A) is EDX figure of Ga which EDX analyzed from the surface of the sample of FIG. 6 (B), (B) is ED ED figure of Ta which EDX analyzed from the surface of the sample of FIG. 6 (B). .

In the SEM cross-sectional photograph shown in FIG. 6A, it was observed that the first GaN layer 102 under the Ta layer 103 was etched to form a cavity 102a. In the SEM surface photograph shown in FIG. 6B, it was observed that the hole 103a was formed on the surface of the Ta layer 103. In addition, the result of having analyzed the surface of the Ta layer 103 containing this hole 103a about Ga and Ta by EDX method is shown to FIG. 7 (A) and (B). This EDX diagram proved that the Ta layer 103 remained and Ga and GaN were thinly grown on the Ta layer 103.

As described above, in the first embodiment, the conditions for forming the second GaN layer 104 using the MOCVD apparatus are adjusted, and the cavity 102a by etching in the first GaN layer 102 using the Ta layer. Made it possible to form. Therefore, when forming the second GaN layer 104 shown in Embodiment 1 described above, the cavity 102a by etching in the first GaN layer 102 with the growth of the first GaN layer 102. ) Can be formed. That is, by forming a metallic material layer on the first GaN layer 102 that generates the etching effect as described above, it becomes possible to form the cavity 102a in the first GaN layer 102. It turned out.

In addition, the setting conditions of the MOCVD apparatus shown in the said Example 1 are an example, What is necessary is just the conditions which can advance the growth of 1st GaN layer mentioned above, and formation of the cavity 102a simultaneously. However, in the growth process of the second GaN layer 104, the growth rate of the first GaN layer 102 is slow compared to the growth rate of the second GaN layer 104, so that in the first embodiment, The setting conditions of the MOCVD apparatus were adjusted in accordance with the growth rate of the first GaN layer 102.

In the first embodiment, although the hole 103a is formed in the Ta layer 103 during the growth process of the second GaN layer 104, for example, the Ta layer 103 is formed. In forming, the Ta layer 103 may be formed using a pattern mask having holes formed in advance. In addition, the shape of the Ta layer 103 is not limited to the above-mentioned stripe shape, and the shape can be changed in various ways.

(Example 2)

In the second embodiment, a process of forming the second GaN layer 104 using the MOCVD apparatus will be described. An example of performing crystal growth for 5 hours by setting the heating temperature to 1045 ° C. while flowing TMGa at a flow rate of 20 μmol / min using TMGa as the source gas. In the second embodiment, a Ta layer 103 having a thickness of 30 nm is formed on the first GaN layer 102 in a stripe shape.

The sample which completed formation of the 2nd GaN layer 104 by the said conditions is shown in FIG. 8 is a SEM cross-sectional photograph that is part of a sample. As is apparent from this figure, a cavity 102a is formed in a part of the first GaN layer 102 below the formation region of the Ta layer 103. In Example 2, holes 103a were formed in the Ta layer 103 in the process of forming the second GaN layer 104.

In the second embodiment, the conditions for forming the second GaN layer 104 are adjusted by using the MOCVD apparatus, and the cavity 102a by etching is formed in the first GaN layer 102 using the Ta layer 103. It was possible to form. Therefore, when forming the second GaN layer 104 shown in the above-described Embodiment 1, the cavity 102a by etching in the first GaN layer 102 together with the growth of the first GaN layer 102. ) Can be formed. That is, by forming a metallic material layer on the first GaN layer 102 that generates the etching effect as described above, the cavity 102a can be formed in the first GaN layer 102. It turned out.

In the cross-sectional view shown in FIG. 8, the cavity 102a is formed by etching in the first GaN layer 102 located below the left and right ends of each Ta layer 103, not directly below the Ta layer 103. Is formed. This indicates that etching in the first GaN layer 102 proceeds from both left and right ends of each Ta layer 103.

In addition, the setting conditions of the MOCVD apparatus shown in the said Example 2 are an example, What is necessary is just the conditions which can advance the growth of the above-mentioned 1st GaN layer, and formation of the cavity 102a simultaneously. However, in the growth process of the second GaN layer 104, the growth rate of the first GaN layer 102 is slow compared to the growth rate of the second GaN layer 104, so in the second embodiment, The setting conditions of the MOCVD apparatus were adjusted in accordance with the growth rate of the first GaN layer 102.

In Example 2, although the hole 103a is formed in the Ta layer 103 during the growth process of the second GaN layer 104, for example, the Ta layer 103 is formed. In forming, the Ta layer 103 may be formed using a pattern mask having holes formed in advance. In addition, the shape of the Ta layer 103 is not limited to the above-mentioned stripe shape, and the shape can be changed in various ways.

(Example 3)

In the third embodiment, a process of forming the second GaN layer 104 using the MOCVD apparatus will be described. An example of performing crystal growth for 5 hours by setting heating temperature to 1045 ° C. while flowing TMGa at a flow rate of 20 μmol / min using TMGa as the source gas is shown. On the first GaN layer 102, in Example 3, A Ta layer 103 having a thickness of 50 nm is formed in a stripe shape.

The sample which completed formation of the 2nd GaN layer 104 by the said conditions is shown in FIG. 9 is a SEM cross-sectional photograph of a portion of the sample. As is apparent from this figure, a cavity 102a is formed in the first GaN layer 102 under the formation region of the Ta layer 103. In Example 3, holes 103a were formed in the Ta layer 103 during the formation of the second GaN layer 104.

In the third embodiment, the conditions for forming the second GaN layer 104 are adjusted by using a MOCVD apparatus, and the cavity 102a by etching is formed in the first GaN layer 102 using the Ta layer 103. Made it possible to form. Therefore, when forming the second GaN layer 104 shown in Embodiment 1 mentioned above, with the growth of the first GaN layer 102, the cavities 102a by etching in the first GaN layer 102. ) Can be formed. That is, by forming a metallic material layer on the first GaN layer 102 that generates the etching effect as described above, the cavity 102a can be formed in the first GaN layer 102. It turned out.

In addition, the setting conditions of the MOCVD apparatus shown in the said Example 3 are an example, What is necessary is just the conditions which can advance the growth of the above-mentioned 1st GaN layer, and formation of the cavity 102a simultaneously. However, in the growth process of the second GaN layer 104, the growth rate of the first GaN layer 102 is slower than the growth rate of the second GaN layer 104, so in the third embodiment, The setting conditions of the MOCVD apparatus were adjusted in accordance with the growth rate of the first GaN layer 102.

In the third embodiment, although the hole 103a is formed in the Ta layer 103 during the growth of the second GaN layer 104, for example, the Ta layer 103 is formed. In forming, the Ta layer 103 may be formed using a pattern mask having holes formed in advance. In addition, the shape of the Ta layer 103 is not limited to the above-mentioned stripe shape, and the shape can be changed in various ways.

Example 4

In the fourth embodiment, a process of forming the second GaN layer 104 using the MOCVD apparatus will be described. An example of performing crystal growth for 5 hours by setting the heating temperature to 1045 ° C. while flowing TMGa at a flow rate of 20 μmol / min using TMGa as the source gas. In the fourth embodiment, a Ta layer 103 having a thickness of 100 nm is formed on the first GaN layer 102 in a stripe shape.

The sample which completed formation of the 2nd GaN layer 104 by the said conditions is shown in FIG. 10 is a SEM cross-sectional photograph of a portion of the sample. As is apparent from this figure, a cavity 102a is formed in the first GaN layer 102 under the formation region of the Ta layer 103. In the fourth embodiment, it was observed that holes 103a were formed in the Ta layer 103 during the formation of the second GaN layer 104.

In the fourth embodiment, the conditions for forming the second GaN layer 104 using the MOCVD apparatus are adjusted, and the cavity 102a by etching in the first GaN layer 102 using the Ta layer 103 is adjusted. Made it possible to form. Therefore, when forming the second GaN layer 104 shown in Embodiment 1 described above, the cavity 102a by etching in the first GaN layer 102 with the growth of the first GaN layer 102. ) Can be formed. That is, by forming a metallic material layer on the first GaN layer 102 that generates the etching effect as described above, the cavity 102a can be formed in the first GaN layer 102. It turned out.

In addition, the setting conditions of the MOCVD apparatus shown in the said Example 4 are an example, What is necessary is just the conditions which can advance the growth of the above-mentioned 1st GaN layer, and formation of the cavity 102a simultaneously. However, in the growth process of the second GaN layer 104, the growth rate of the first GaN layer 102 is slower than the growth rate of the second GaN layer 104, so that in the fourth embodiment, The setting conditions of the MOCVD apparatus were adjusted in accordance with the growth rate of the first GaN layer 102.

In the fourth embodiment, the hole 103a is formed in the Ta layer 103 during the growth of the second GaN layer 104. However, for example, the Ta layer 103 is formed. In forming, the Ta layer 103 may be formed using a pattern mask having holes formed in advance. In addition, the shape of the Ta layer 103 is not limited to the above-mentioned stripe shape, and the shape can be changed in various ways.

(Example 5)

In Example 5, the specific example of forming the 2nd GaN layer 104 on the board | substrate 101 by changing the setting conditions of a MOCVD apparatus is demonstrated.

In Example 5, the heating temperature is set to 1045 ° C. while TMGa is flowed at 87 μmol / min using TMGa as the source gas, and crystal growth is performed for 5 hours.

The sample which completed formation of the 2nd GaN layer 104 by the said conditions is shown in FIG. In FIG. 11, (A) is a SEM cross-sectional photograph of a part of a sample, (B) is a SEM surface photograph which partially enlarged the surface of (A). As is apparent from this figure, a granular material is deposited on the surface of the second GaN layer 104, and the cavity is formed in the first GaN layer 102 under the formation region of the Ta layer 103. 102a) is formed. The granular material was found to be Ga particles, N particles, and Ta particles by the following EDX analysis and CL analysis.

The result of EDX analysis of the surface of the said particulate matter is shown in FIG. In FIG. 12, (A) is the spectral diagram which EDX analyzed the granular material of FIG. 11 (B), (B) is the EDX diagram of Ga which EDX analyzed the granular material of FIG. 11 (B), (C) is It is EDX diagram of N which EDX analyzed the granular material of FIG. 11 (B). Ga and N and some Ta were observed as shown in the spectral diagram of FIG. 12 (A), and Ga and N were observed as shown in the EDX diagram of FIGS. 12 (B) and (C).

Moreover, the result of EDX analysis of the cross section of a granular material is shown to FIG. 13 and FIG. In FIG. 13, (A) is the SEM cross-sectional photograph which enlarged the void part as a granular material of FIG. 11 (B), (B) is the spectral diagram which EDX analyzed the cross section of (A). In FIG. 14, (A) is the EDX figure of Ga which EDX analyzed the cross section of FIG. 13A, (B) is the EDX figure of N which EDX analyzed the cross section of FIG. 13A, (C) is It is EDX figure of Ta which EDX analyzed the cross section of FIG. 13 (A).

As shown in the spectral diagram of Fig. 13B, Ga and N of the second GaN layer 104 and the particulate matter, Ta of the Ta layer 103, and Al and O of the sapphire substrate 101 were observed. Moreover, as shown to FIG. 14 (A)-(C), Ga, N, Ta was observed in the void part.

From the above observation results, it was found that the granular material deposited on the surface of the second GaN layer 104 was Ga particles, N particles, and Ta particles. That is, in the fifth embodiment, it was found that Ga in the etched portion of the first GaN layer 103 was broken with N, GaO reaction and gasification were lost, and Ga particles, N particles, and Ta particles were precipitated. It became.

As mentioned above, in Example 5, since the flow volume of TMGa was set more than Example 1 at 87 micromol / min, it turned out that the above-mentioned granular material precipitated on the board | substrate. Therefore, it turned out that the preferable flow volume X of TMGa which a granular material does not precipitate on a board | substrate is the range of X <87 micromol / min.

In addition, in Example 5, it can be seen that reaction by-products are generated as the cavity 102a is formed. This reaction byproduct may precipitate on the substrate and may evaporate and adhere to the chamber walls.

(About Ta ₂ O ₅ formation of Ta layer)

In Examples 1 to 4, an example of changing the thickness of the Ta layer 103 to 30 nm, 50 nm, and 100 nm is shown. Thus, even if the thickness of the Ta layer 103 is changed, it can be confirmed that the cavity 102a is formed in the 1st GaN layer 104 by etching.

The Ta layer 103 schematically shows in FIG. 15 that a region where Ta ₂ O ₅ is generated varies with its thickness. 15 (A) shows an example in which the Ta layer 103 having a thickness of 5 nm is changed to Ta ₂ O ₅ , and FIG. 15 (B) shows that the surface of the Ta layer 103 having a thickness of 100 nm has Ta ₂ O. FIG. _The example which changed to ₅ is shown. After the Ta layer 103 is deposited on the surface of the first GaN layer 102 by the EB deposition apparatus, the Ta layer 103 is exposed to the atmosphere during the transfer to the MOCVD apparatus. In the meantime, it was found that Ta and oxygen reacted to change the Ta layer 103 into Ta ₂ O ₅ . For this reason, a thickness of 15 Ta layer 103 is Ta layer 103 as shown in, Figure 15, and the total change in Ta ₂ O ₅ (B), when a thickness of 5nm in that appears in (A) in 100nm If it was found that the surface is changed to Ta ₂ O _5. That is, Ta is in contact with air at room temperature, produces the Ta ₂ O _5. 15A schematically shows an example in which a Ta film having a thickness of 5 nm grows in the transverse direction on the GaN layer. 16 shows an example in which Ta ₂ O ₅ having a thickness of 10 nm is actually grown in the transverse direction on the substrate. In both cases, growth is progressing without etching the GaN layer under the Ta film. That is, when a substrate on which a Ta film having a thickness of 5 nm was formed was transferred to the MOCVD apparatus in air, 5 nm Ta ₂ O ₅ was formed in FIG. 15 (A). Ta ₂ O ₅ is a very good transverse mask. On the other hand, when Ta of 100 nm in thickness shown in Fig. 15B is formed, the circumstances are different. When Ta is formed by EB vapor deposition, since Ta of a raw material is mounted in air, a thin oxide film is deposited on Ta surface. Further deposition of this leads to Ta ₂ O ₅ at first, but this state gradually decreases to the deposition of Ta metal. Therefore, the thickness of the GaN layer of Ta ₂ O ₅ is 5nm or less Ta, and is partially contained in the Ta portion. The upper layer from this Ta ₂ O ₅ film is Ta. Then, the Ta ₂ O ₅ film is thinly formed on the surface of the Ta layer by transferring the substrate after Ta layer formation to the MOCVD apparatus in air. As a result, the surface of the Ta layer is thinly wrapped with a Ta ₂ O ₅ film. Among these Ta layers, the Ta ₂ O ₅ film on the GaN layer becomes a layer in which Ta is partially mixed. This state is shown typically in FIG.15 (B). N in the GaN layer and Ta in the Ta layer combine to form TaN. However, since Ga is the same as Ga deposited during gas phase growth, it is used as a raw material.

In the first to fourth embodiments, the Ta ₂ O ₅ region oxidized by the Ta layer 103 grows laterally with respect to the first GaN layer 104 to act as a very good etching mask. Therefore, the second embodiment, as in shown in Figure 8, GaN layer of a first to a thickness of the right and left end portions of the Ta layer 103 of 30nm are not forming a Ta ₂ O ₅ region, is located in the lower layer of the part ( It was found from 102 that the formation of the cavity 102a proceeded. Also in Embodiments 3 and 4 in which Ta layers 103 having thicknesses of 50 nm and 100 nm were formed, since Ta ₂ O ₅ regions were formed on the surface thereof, and acted as etching masks on the first GaN layer 104, Similarly, formation of the cavity 102a proceeds.

Therefore, the thickness of the Ta layer 103 is a region formed of Ta ₂ O ₅ acts as an etching mask, in Examples 1 to Embodiment 4 may be a 20nm ~ 100nm, as shown in. In addition, in FIG. 16 (A) which shows an example in which a Ta mask having a thickness of 5 nm is formed on the first GaN layer, no cavity is formed under the Ta mask. Further, in the Ta ₂ O 16 an illustrative example only and forming a mask ₅ (B), it was confirmed that the Ta ₂ O ₅ capable of forming a mask on the GaN layer, and InGaAlN. Therefore, since the Ta ₂ O ₅ mask is formed regardless of the thickness of the Ta layer 103, as shown in the above Examples 1 to 4, the first GaN layer (located under the Ta ₂ O ₅ mask) ( It is possible to advance the formation of the cavity 102a in the 102.

(Embodiment 2)

Next, the case where LED is formed as a light emitting element using the compound semiconductor layers shown in the first embodiment will be described with reference to FIG.

17 is a partial cross-sectional view for explaining the LED according to the second embodiment.

In FIG. 17, a plurality of LEDs 200 are formed isolated from each other on a substrate 100 on which a second GaN layer 104 is formed. Each LED 200 has a lower semiconductor layer 201 made of a first conductivity type compound semiconductor layer, and an active layer 202 and an upper semiconductor layer 203 made of a second conductivity type compound semiconductor layer. The active layer 202 may have a single or multiple quantum well structure having a well layer and a barrier layer, and its material and composition are selected by the required emission wavelength. For example, the active layer 202 may be formed of a gallium nitride compound semiconductor. The lower and upper semiconductor layers 201 and 203 may be formed of a material having a larger band gap than the active layer 202, and may be formed of a gallium nitride compound semiconductor.

On the other hand, the upper semiconductor layer 203 is located above a part of the lower semiconductor layer 201, and the active layer 202 is interposed between the upper semiconductor layer 203 and the lower semiconductor layer 201. In addition, the upper electrode layer 204 may be formed on the upper semiconductor layer 203. The upper electrode layer 204 may be formed of a transparent electrode layer, for example, an indium tin oxide film (ITO) or a material such as Ni / Au.

In addition, the upper electrode pad 205 is formed on the upper electrode layer 204, and the lower electrode 207 is formed in the region where the lower semiconductor layer 201 is exposed.

In this manner, after the plurality of LEDs 200 are formed on the second GaN layer 100, the plurality of LEDs 200 can be separated into individual LEDs 200 by cutting at the cutting positions shown in the drawing. The sapphire substrate 101 may be peeled off before separating into individual LEDs 200. It may also be peeled off before forming the individual LEDs 200.

In addition, when forming the LED 200 on the second GaN layer 104, by forming a compound semiconductor in which the refractive indexes of the second GaN layer 104 and the lower semiconductor layer 201 are different from each other, It is possible to improve the luminous efficiency and to configure a high brightness LED array. In addition, when the laser diode is formed by using the second GaN layer 104, since it is formed on the GaN layer having better thermal conductivity than the sapphire substrate 101, the heat dissipation characteristics can be improved and the life of the laser diode can be extended. .

(Embodiment 3)

Next, the manufacturing method of the light emitting element of a vertical structure is demonstrated with reference to FIG.

In Fig. 18A, as described with reference to Figs. 1A to 1C, a sapphire substrate having a first GaN layer 102 and a Ta layer 103 formed in a pattern shape (first substrate, 101 is loaded into the first chamber (10 in FIG. 2), and a second GaN layer 104 is formed. At this time, the cavity 102a is formed in the first GaN layer 102. In addition, a hole 103a may be formed in the Ta layer 103 while the second GaN layer 104 is formed, and the hole 103a is previously formed through patterning before forming the second GaN layer 104. It may be formed. The substrate on which the second GaN layer 104 and the cavity 102a are formed is transferred to a second chamber (20 in FIG. 2), and in the second chamber 20, the first conductive compound semiconductor layer 301 and the active layer ( 302 and the second conductivity type compound semiconductor layer 303 are formed.

The first conductive compound semiconductor layer, the active layer, and the second conductive compound semiconductor layer may be gallium nitride-based compound semiconductors, and may be formed using an organometallic vapor phase growth method. The active layer 302 may be formed in a single or multiple quantum well structure, and its material and composition are selected by the required emission wavelength. The first and second conductivity type compound semiconductor layers 301 and 303 are formed of a material having a larger band gap than the active layer 202.

In FIG. 18B, after the growth of the compound semiconductor layers is completed, the substrate 101 is taken out of the second chamber 20, and the second substrate 400 is disposed on the second conductive compound semiconductor layer 303. Attach. The second substrate 400 may be a metal having good thermal conductivity or a silicon-based substrate such as Si or SiC. The second substrate 400 may be attached on the second conductive compound semiconductor layer in various ways, for example, using a bonding metal.

After the second substrate 400 is attached, the sapphire substrate 101 is separated from the second GaN layer 104. The sapphire substrate 101 may be removed by laser lift off, wet etching, or polishing. Although the first GaN layer 102 positioned at the interface between the sapphire substrate 101 and the first GaN layer 102 is shown as being removed, the present invention is not limited thereto and only a part of the first GaN layer 102 may be removed.

In Fig. 18C, after the sapphire substrate 101 is peeled off, the peeling surface is planarized by RIE or polishing. In this case, the second GaN layer 104 may be removed by polishing to expose the first conductivity-type semiconductor layer 301. Alternatively, when the second GaN layer 104 is of the first conductivity type, the second GaN layer 104 may remain.

In FIG. 18D, a lower electrode pad 401 is formed on the second substrate 400, and an upper electrode pad 402 is formed on the peeling surface side. Thereafter, the light emitting device having the vertical structure shown in FIG. 18D is completed by separating the light emitting devices into individual light emitting devices.

The first conductive semiconductor layer may be a gallium nitride-based n-type compound semiconductor, and the second conductive semiconductor layer may be a gallium nitride-based p-type compound semiconductor. Accordingly, a roughened surface may be formed on the release surface, for example, the surface of the first conductivity type semiconductor layer 301 by using a photochemical etching technique.

In the third embodiment, a method of manufacturing a light emitting device having a vertical structure has been described. However, as described in the second embodiment, after the sapphire substrate 101 is peeled off, the light emitting device having a horizontal structure is formed on the second substrate 400. It may be prepared.

As described above, by forming a cavity in the first GaN layer on the growth substrate such as sapphire, the growth substrate can be easily peeled off, thereby lowering the manufacturing cost of the light emitting device. In addition, by separating the first chamber and the second chamber, it is possible to prevent the deterioration quality of the compound semiconductor layer from the reaction by-products generated during the formation of the cavity.

In the above embodiments, the Ta layer is formed as the metallic material layer. However, alloys of a plurality of metals, alloys such as metals and semiconductors, and the like can be used, and the first GaN layer is etched. What is necessary is just a metallic material which exhibits an effect.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the manufacturing method of the light emitting element which concerns on Embodiment 1 of this invention, (A) is sectional drawing which shows the process of forming a 1st GaN layer and Ta layer, (B) is a 2nd GaN layer. And sectional drawing showing a cavity formation process, (C) is sectional drawing which shows the process of forming a compound semiconductor layer on a 2nd GaN layer.

2 is a schematic diagram of a light emitting device manufacturing apparatus used to form the second GaN layer and the compound semiconductor layers.

3 is a SEM cross-sectional photograph of a sample produced in accordance with Example 1. FIG.

4 is a spectral diagram of EDX of a sample according to Example 1. FIG.

5 is a SEM cross-sectional photograph of the enlarged region of FIG. 3, (B) is an EDX of Ga, (C) is an EDX of Al, and (D) is an EDX of O.

6 is a SEM cross-sectional photograph of a sample according to Example 1, and (B) is a SEM surface photograph of a sample.

7 is an EDX diagram according to Example 1, (A) is an EDX diagram of Ga, and (B) is an EDX diagram of Ta.

8 is a SEM cross-sectional photograph of a sample according to Example 2. FIG.

9 is a SEM cross-sectional photograph of a sample according to Example 3. FIG.

10 is a SEM cross-sectional photograph of a sample according to Example 4. FIG.

(A) according to Example 5 is an SEM bird's eye photograph, (B) is a SEM surface photograph.

FIG. 12 is a spectral diagram of EDX of FIG. 11 (B), (B) is EDX diagram of Ga of FIG. 11 (B), and (C) is N of FIG. EDX is also.

FIG. 13 is a SEM cross-sectional photograph of a void according to Example 5, and (B) is an EDX spectrum diagram of (A).

Fig. 14 is a diagram showing ED ED of Ga of Fig. 13A, Fig. 13B is a diagram of ED ED of N of Fig. 13A, and Fig. 13C shows Ta of Fig. 13A. EDX is also.

Fig. 15 is a diagram schematically showing an example in which a Ta layer having a thickness of 5 nm is changed to Ta ₂ O ₅ , and (B) is a diagram schematically illustrating an example in which the surface of a Ta layer having a thickness of 100 nm is changed to Ta ₂ O ₅ . It is a figure shown normally.

Fig. 16 (A) is a SEM surface photograph of a substrate on which a Ta mask having a thickness of 5 nm is formed, and (B) is a SEM cross-sectional photograph of a substrate on which a Ta ₂ O ₅ mask having a thickness of 10 nm is formed.

17 is a cross-sectional view showing the configuration of an LED array according to Embodiment 2 of the present invention.

18 is a cross-sectional view showing a light emitting device manufacturing method according to Embodiment 3 of the present invention.

Claims (11)

Loading a substrate having a first semiconductor layer and a metallic material layer formed in a pattern shape on the first semiconductor layer into a first chamber, Forming a second semiconductor layer on the first semiconductor layer and on the metallic material layer in the first chamber, and forming a cavity in the first semiconductor layer below the metallic material layer; Transferring the substrate having the second semiconductor layer from the first chamber to a second chamber, And forming a compound semiconductor layer on the second semiconductor layer in the second chamber. The method according to claim 1, Transferring the substrate is performed without vacuum breaking. The method according to claim 1, The metallic material layer is formed on the first semiconductor layer in a stripe shape at regular intervals and widths, The second semiconductor layer covers the metallic material layer. The method according to claim 1, Wherein said metallic material layer has an oxide film and said oxide film forms a mask for said first semiconductor layer. The method according to claim 4, The metal material layer is formed to a thickness in which a plurality of holes are formed in the first semiconductor layer and the second semiconductor layer. The method according to claim 1, The first semiconductor layer and the second semiconductor layer are formed using the same or different compound semiconductor material, The metallic material layer is formed using a metallic material having a higher melting point than the heating temperature at the time of forming the second semiconductor layer. The method according to claim 1, The metallic material layer has an oxide film, the oxide film forms a mask for the first semiconductor layer, and forms a plurality of holes through the first semiconductor layer and the second semiconductor layer, When the second semiconductor layer is formed using the organometallic vapor phase growth method, the first semiconductor layer below the portion where the metallic material layer is formed is reacted with the metallic material layer and oxygen to evaporate from the plurality of holes. To form the cavity. The method according to claim 1, The metallic material layer is tantalum, the film thickness thereof is thicker than 5 nm, and after formation on the first semiconductor layer, the surface of the tantalum is covered with tantalum oxide, and the first semiconductor layer is formed of the tantalum. A method of manufacturing a light emitting device, wherein an interface is surrounded by tantalum and tantalum oxide. The method according to claim 1, The substrate is a light emitting element manufacturing method, characterized in that the sapphire substrate or silicon substrate. The method according to claim 1, Forming the compound semiconductor layer Forming a first compound semiconductor layer, An active layer is formed on the first compound semiconductor layer, Forming a second compound semiconductor layer on the active layer. The method according to claim 10, Attaching a secondary substrate on the second compound semiconductor layer, And peeling said substrate using said cavity formed in said first semiconductor layer.

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