JP5131889B2 - Method of manufacturing nitride compound semiconductor device - Google Patents

Description

The present invention relates to the production how the nitride-based compound semiconductor device.

  Nitride-based compound semiconductor blue light-emitting elements are used for large-screen displays and liquid crystal backlights, and research and development are underway for future lighting applications.

  FIG. 1 is a configuration diagram illustrating an example of a conventional blue light emitting element. As shown in FIG. 1, a conventional light emitting device 10 includes a low-temperature buffer layer 12, an n-type contact layer 13, an n-type cladding layer 14, a light-emitting layer 15, and a p-type cladding on an electrically insulating sapphire substrate 11 sequentially. The layer 16, the p-type contact layer 17 and the p-type electrode 18 are formed, and the formed multilayer film structure is etched in the thickness direction to expose the n-type contact layer 13, on which the n-type electrode is formed. 19 is formed. In the light emitting device having such a configuration, the n-type and p-type electrodes are provided on the surface of each of the n layer and the p layer on the same side of the epitaxial layer surface grown by metal organic vapor phase epitaxy. Was substantially smaller.

  From this point of view, a light emitting device having a structure as shown in FIG. 2 has been developed and studied for practical use. In the light emitting device 20 shown in FIG. 2, an n-type cladding layer 24, a light emitting layer 25, a p-type cladding layer 26, and a p-type contact layer 27 are sequentially formed on the growth substrate layer 22, and a p-type contact layer is formed. A p-type electrode 28 and an n-type electrode 29 are formed so as to oppose each other on 27 and the growth substrate layer 29. In the light emitting element having such a configuration, electrodes are provided on different upper and lower surfaces of the element so that current can be conducted vertically. According to such a configuration, since the number of light emitting elements per substrate can be increased, the manufacturing cost of the elements can be reduced.

  There are three main methods for making a vertically conductive light emitting element structure. The first is a method of performing epitaxial growth on a conductive substrate having a thickness of about 300 μm, and the second is a method in which an epitaxially grown layer and a conductive substrate having a thickness of about 300 μm are bonded to each other, and then electrically insulated. The third method is to separate the active substrate, and after the epitaxial growth substrate layer having a thickness of about 100 μm is formed on the base slope having a thickness of about 300 μm by high-speed growth, the functional layer of the light emitting part having a good crystal performance is formed by low-speed growth epitaxial growth. A method for separating a substrate.

As for the conductive substrate of the first method, a SiC substrate has already been used, but there is a problem that the substrate is difficult to process and is expensive. Further, nitride substrates such as GaN and AlN, boride base plates of ZrB ₂ , oxide substrates such as Ga ₂ O _3, and semiconductor substrates such as GaAs and Si have been studied. Substrates and oxide substrates are more difficult to process than sapphire substrates and have problems such as high costs. On the other hand, semiconductor substrates have a problem that light emission is absorbed by the substrate and is opaque to visible light.

  The second bonded substrate method has a problem that the process becomes long and the substrate needs to be separated and the cost becomes high, so that an inexpensive separation process needs to be developed.

  The third method is a method using a vapor phase growth method. After a growth substrate layer serving as a nitride compound semiconductor substrate having a thickness of about 100 μm is grown on the substrate by a chloride vapor phase growth method, This is a method in which a functional nitride compound semiconductor such as a double heterostructure of a light emitting portion is grown by an organic metal compound vapor phase growth method, and then the substrate is separated. However, this method requires vapor phase growth apparatuses having different performances, and there is a problem that the process time due to the temperature increase / decrease of growth becomes long in each apparatus.

  Regarding the separation process of the substrate and the growth layer, there is a method in which after crystal growth, a laser is irradiated from the transparent substrate side to the vicinity of the growth interface of the substrate to raise the temperature, and the growth substrate layer portion near the growth interface is decomposed and separated. However, the cost is high.

  For this reason, a method of separating the substrate by causing a peeling phenomenon between the substrate and the growth layer during crystal growth or during cooling after crystal growth has been studied. Specifically, a metal Ti film is formed on a sapphire C-plane, A-plane, or R-plane substrate, and a nitriding treatment is performed to form a TiN film having micropores, which is 250 μm thick by chloride vapor deposition. After the growth of GaN, GaN can be separated from the sapphire substrate naturally during the cooling process from the voids formed in the GaN by the action of the metal Ti film and TiN film, and the GaN interface has fine irregularities For this reason, a method of performing a polishing finish has been examined (Patent Document 1).

In addition, the surface of the sapphire substrate is made uneven, GaN is grown without coating SiO ₂ only on the bottom of the recess, and peeling occurs when cooled at a cooling rate of about −100 ° C./min to −0.5 ° C./min. It is disclosed that a GaN substrate having an uneven back surface is obtained, and that a peeling phenomenon occurs even at a high temperature during crystal growth when the thickness of the growth layer is 50 μm or more (Patent Document 2). In this method, after crystal growth, it is separated and separated when taken out from the vapor phase growth apparatus, and the separation step of the growth layer and the substrate becomes unnecessary, but for polishing or substrate pretreatment process, Cost increases. Further, when the growth layer has a thickness of 50 μm or less, natural peeling is difficult. Therefore, it is necessary to develop a method that causes natural peeling even when the thickness is small.

  On the other hand, when a high-temperature buffer layer is deposited on the sapphire substrate, that is, at a temperature of 1200 to 1300 ° C., an Al-rich composition such as AlN is epitaxially grown on the sapphire substrate to a thickness of 1-3 μm. It is disclosed that cracks and peeling occur at the interface (Patent Document 3).

From the above viewpoints, no practical method has been developed in the past for efficiently producing a nitride-based compound semiconductor device such as a light-emitting device configured as shown in FIG. Met.
JP2004-39810 JP2004-55799 JP2003-45599

  An object of the present invention is to establish a method capable of efficiently producing a vertical conduction type nitride compound semiconductor device.

In order to achieve the above object, the present invention provides:
It has a main surface off from the C surface of the sapphire substrate, a main surface off from the R surface of the sapphire substrate in a plane including the c axis, or a main surface off from the R surface of the sapphire substrate to the opposite side to the c axis. Preparing a sapphire substrate;
Pre-flowing an organic metal containing at least Al on the sapphire substrate to form a metal layer made of an aluminum metal alone or an alloy of aluminum and gallium ;
Forming a buffer layer made of a nitride compound semiconductor having a composition of AlGaN on the metal layer;
Forming a growth substrate layer made of a nitride compound semiconductor on the buffer layer;
Forming a functional layer made of a nitride compound semiconductor on the growth substrate layer;
Peeling the sapphire substrate and the buffer layer through the metal layer to obtain a nitride-based compound semiconductor device including at least the growth substrate layer and the functional layer;
The present invention relates to a method for manufacturing a nitride-based compound semiconductor device.

  The inventors of the present invention have intensively studied to achieve the above object. As a result, in a sapphire substrate that is currently used commercially, instead of the general-purpose main surface C-plane, A-plane, R-plane, etc., the main plane off by an appropriate angle from the C-plane, or Using a principal surface that is off from the R plane in a plane including the c-axis, an organic metal containing at least Al is preflowed on a sapphire substrate having such a principal surface, and a metal layer containing at least Al has a predetermined thickness. In addition, a buffer layer made of a nitride compound semiconductor having a composition of AlGaN is formed on the metal layer at a predetermined temperature, and then a growth substrate layer constituting the target nitride compound semiconductor and By forming each functional layer with a predetermined thickness, after the functional layer is formed, the sapphire substrate and the buffer layer may generate cracks or the like through the metal layer. It was found to be peeled off without.

  Therefore, based on the above-described method, it is widely used as a substrate, and a relatively inexpensive sapphire substrate is used, and a normal process can be performed without requiring complicated processes such as laser light irradiation and formation of an uneven surface. A nitride-based compound semiconductor element including at least the growth substrate layer and the functional layer can be obtained only by the film technique. Then, by forming electrodes on the growth substrate layer and the functional layer so as to face each other, it is possible to easily form a light emitting element having a structure as shown in FIG.

  As described above, according to the present invention, it is possible to provide a method capable of efficiently manufacturing a vertical conduction type nitride compound semiconductor element.

  The details of the present invention and other features and advantages will be described in detail below based on the best mode.

(Preparation of sapphire substrate)
In the present invention, first, a sapphire substrate having a main surface turned off from the C surface of the sapphire base or a main surface turned off from the R surface of the sapphire substrate to the opposite side to the c-axis is prepared. As described in detail below, the off-angle is formed by sequentially forming a metal layer, a buffer layer, a growth substrate layer, and a functional layer on the sapphire substrate, and then the sapphire substrate and the buffer via the metal layer. The layer is not particularly limited as long as it can be peeled off without causing cracks.

  However, the sapphire substrate is turned off within a range of 0.05 degrees to 1 degree from the C plane, or 0.25 degrees to 0.75 degrees within the plane including the c axis from the C plane. It is preferable that it is off in the range. In such a case, when the sapphire layer and the buffer layer are peeled, the flatness of the peeled surface can be further improved.

  In addition, when the off angle is out of the above range, the peeling may not be performed well, and unevenness may occur on the peeling surface and the flatness may be impaired.

(Formation of metal layer)
In this invention, after preparing the sapphire substrate which has the main surface turned off as mentioned above, the metal layer which consists of an aluminum metal simple substance or an alloy of aluminum and gallium is formed on this sapphire substrate. This metal layer is formed by preflowing an organic metal containing at least Al with respect to the sapphire substrate, for example, using an MOCVD method or the like.

Incidentally, the metal layer, from the viewpoint of wettability and stability, Ri Do aluminum metal alone or an alloy of aluminum and gallium, in particular, is preferably made of aluminum metal alone.

  As the organic metal, a general-purpose organic metal (gas) such as trimethylaluminum can be used. When the metal layer is made of an alloy of aluminum and gallium, a general-purpose organometallic gas such as trimethylgallium can be used in addition to the trimethylaluminum.

  Further, the metal layer preferably has a thickness in the range of 1 atomic layer to 20 atomic layers, more preferably in the range of 1 atomic layer to 5 atomic layers, particularly 1 atomic layer to 3 atoms. The range of the atomic layer is preferable. By setting the thickness of the metal layer in such a range, as described above, the separation between the sapphire substrate and the buffer layer via the metal layer is caused by the large stress generated at the interface, and the separation surface. Can be implemented more easily in a state in which is kept flat. Moreover, the formation temperature of the buffer layer formed on the metal layer can be lowered by about 100 ° C. compared to the conventional case, and the thermal load on the growth apparatus can be reduced.

  If the thickness of the metal layer is smaller than the above range, it may be difficult to cover the sapphire substrate uniformly, and the sapphire substrate and the buffer layer may not be sufficiently separated. Further, when the thickness of the metal layer is thicker than the above range, it becomes polycrystalline by forming crystal nuclei by ammonia flow after preflow, and stress relaxation occurs at the interface between the sapphire substrate and the buffer layer, In some cases, peeling cannot be performed sufficiently.

(Formation of buffer layer)
In the present invention, after an Al-containing metal layer is formed on a sapphire substrate as described above, a buffer layer made of a nitride compound semiconductor having a composition of AlGaN is formed by, for example, the MOCVD method. The conditions for forming the buffer layer are not particularly limited as long as the buffer layer can be sufficiently separated from the sapphire substrate through the metal layer as described above. However, preferably, the peeling can be performed more stably and stably by forming at a temperature of 1100 ° C. or higher.

  On the other hand, the upper limit of the formation temperature of the buffer layer is preferably 1550 ° C. When the buffer layer is formed at a temperature exceeding 1550 ° C., the surface of the buffer layer itself may become rough, and the surface flatness may deteriorate.

  The conventional buffer layer is formed at a low temperature of 400 ° C. to 900 ° C. In the present invention, the buffer layer is preferably formed at a temperature of 1100 ° C. or higher and 1550 ° C. or lower as described above. Therefore, it can be seen that the formation temperature of such a buffer layer is sufficiently higher than the conventional formation temperature.

  In addition, the inventors of the present invention have 0.25 degrees on a substrate having a main surface that is off in a range of 0.05 degrees to 1 degree from the C plane of the sapphire substrate, or in a plane including the c axis from the R plane. When a (low temperature) buffer layer is deposited at a temperature of 900 ° C. or lower on a substrate that is turned off by about 0.75 ° C., and a growth substrate layer as described below is formed on the buffer layer, the growth substrate layer It has been confirmed that crystallinity is improved. This is thought to be due to the fact that step growth is more likely to occur than frequency growth, and that screw dislocations are reduced, and that edge dislocations are also reduced because growth is easy from a kink surface in which both positions are determined.

  However, in this case, even if the growth substrate layer is thick, for example, 10 μm or more, cracks may occur at the interface between them without causing separation between the sapphire substrate and the buffer layer. Also from such a viewpoint, as described above, the formation temperature of the buffer layer is preferably 1100 ° C. or higher.

  For the same reason as the formation temperature, the Al content in the group III element in the AlGaN composition constituting the buffer layer is preferably 90 atomic% or more, and more preferably 100%. The layer is preferably composed of AlN.

  Furthermore, it is preferable that the flow rate ratio of the group III element source gas and the group V element source gas when forming the buffer layer is 10 to 1000. In this case, for example, the generation of adducts and oligomers of a group V organic source gas such as ammonia and a group III organic metal source is suppressed, and further, a change in the surface of the sapphire substrate is suppressed and stress relaxation is caused. It is possible to effectively avoid doping with high concentration of carbon that makes peeling through the metal layer difficult.

  Further, from the viewpoint of ensuring the surface flatness of the buffer layer itself, the thickness of the buffer layer is preferably 0.3 μm or more, and more preferably 1 μm to 10 μm.

  The group III element source gas may be a general-purpose organic metal (gas) such as trimethylaluminum described above, and the group V source gas may be an alkyl hydrazine in addition to the ammonia. it can. Alkyl hydrazine is monomethyl hydrazine, dimethyl hydrazine, and tertiary butyl hydrazine. The growth rate when using alkyl hydrazine is usually greater than the growth rate of ammonia. However, ammonia is preferable from the viewpoint of safety.

(Formation of growth substrate layer)
In the present invention, after the (high temperature) buffer layer is formed as described above, the growth substrate layer is formed by, for example, the MOCVD method. In this case, the thickness of the growth substrate layer is formed to a thickness of 10 μm or more for the purpose of imparting sufficient mechanical strength to function as a substrate in the target nitride compound semiconductor device.

  Further, when such a relatively thick growth substrate layer is formed, it is preferably formed at a high growth rate from the viewpoint of cost reduction. Specifically, it is preferably 3 μm / hour or more, more preferably 20 μm / hour or more, and particularly preferably 50 μm / hour or more. From the viewpoint of maintaining the surface flatness of the growth substrate layer, the upper limit of the growth rate is preferably set to 100 μm / hour.

  In order to realize such a high growth rate, it is necessary to improve the decomposition efficiency of the group V source gas. For example, the piping outlet of the group V source gas is brought close to the susceptor on which the sapphire substrate is installed and the face down type is used. And by increasing the contact time with the high-temperature susceptor.

  Moreover, it is preferable that the flow rate ratio of the group III element source gas and the group V element source gas when forming the growth substrate layer is 10 to 1000. In this case, for example, generation of adducts and oligomers due to a group V organic source gas such as ammonia and a group III organic metal source can be suppressed.

  Examples of the group III element source gas include general-purpose organic metals (gas) such as trimethylaluminum and trimethylgallium. Examples of the group V source gas include alkylhydrazine in addition to the ammonia. Can do. Alkyl hydrazine is monomethyl hydrazine, dimethyl hydrazine, and tertiary butyl hydrazine. The growth rate when using alkyl hydrazine is usually greater than the growth rate of ammonia. However, ammonia is preferable from the viewpoint of safety.

  The upper limit of the thickness of the growth substrate layer is not particularly limited, but is set to 1 mm, for example. Even if the thickness is increased beyond this, not only the handling when functioning as the substrate of the target nitride-based compound semiconductor device is facilitated, but also the film formation time is prolonged and the cost is increased.

(Formation of functional layer)
In the present invention, after the growth substrate layer is formed as described above, a functional layer that exhibits the substantial function of the target nitride-based compound semiconductor element is formed on this layer. This functional layer can be, for example, a light emitting layer, a light receiving layer, or a high mobility electronic circuit layer. In the case of the light emitting layer, the functional layer has a structure of, for example, n-type contact layer / n-type cladding layer / active layer / p-type cladding layer / p-type contact layer.

  Further, in order to obtain good characteristics of the functional layer, the growth rate is preferably 10 μm / hour or less, and more preferably 5 μm / hour or less. In particular, when the functional layer is a light emitting layer, the growth rate of the active layer is low, and is about 0.1 μm / hour to 0.5 μm / hour.

  The total thickness of the buffer layer, the growth substrate layer, and the functional layer described above is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 40 μm or more. Accordingly, a sufficiently large stress can be generated at the interface between the sapphire substrate and the buffer layer described above, and peeling through the metal layer at the interface can be performed easily and effectively.

(Peeling of sapphire substrate and buffer layer)
When the above-described steps are performed and an Al-containing metal layer, a (high temperature) buffer layer, a growth substrate layer, and a functional layer are sequentially formed on the sapphire substrate, the sapphire substrate and the buffer layer are formed after the formation. Peel naturally through the layers. This can be caused by, for example, natural cooling by forming each layer as described above and then removing it from a predetermined film forming apparatus. It can also be produced by a sufficiently low cooling rate of, for example, about 20 ° C./min.

  After the delamination as described above occurs, a nitride-based compound semiconductor element including the buffer layer, the growth substrate layer, and the functional layer is formed. It can be removed by dipping in an acid solution to dissolve or polishing.

  Thereafter, by forming electrodes on the main surface of the remaining growth substrate layer and the main surface of the functional layer so as to face each other, a vertically conductive nitride compound semiconductor element as shown in FIG. 2 is obtained. Can be obtained.

  FIG. 3 schematically shows the entire layer structure before peeling occurs at the interface between the sapphire substrate and the buffer layer. The layer structure 30 is formed by sequentially forming an Al-containing metal layer 32, a (high temperature) buffer layer 33, a growth substrate layer 34, and a functional layer 35 on the sapphire substrate 31 having the main surface turned off as described above.

Example 1
A sapphire substrate with off-angles of 0.2 degrees and 0.4 degrees from the sapphire C surface is placed on a substrate holder inside a horizontal metal organic vapor phase apparatus, and the substrate surface temperature is set to 1200 ° C. while flowing hydrogen gas. The substrate surface was cleaned for a minute.

  Next, the substrate surface temperature was lowered to 1400 ° C., the main carrier gas was hydrogen, trimethylaluminum (TMA) was supplied for 6 seconds, and the Al layer was grown to a thickness of 2 atomic layers. The thickness of the Al layer is calculated from the Al growth rate.

  Next, the substrate surface temperature was maintained at 1400 ° C., the main carrier gas was hydrogen, ammonia and TMA were supplied at a V / III ratio = 100, and an AlN buffer layer was grown to a thickness of 1 μm at a pressure of 100 torr.

  Next, the substrate surface temperature is lowered to 1050 ° C., and trimethylgallium is started to flow with the monosilane as a doping agent so that the ammonia / hydrogen ratio is 0.7 and the V / III ratio is 100, and grown for 120 minutes. A GaN growth substrate layer was created. Thereafter, the supply amount of ammonia was increased, the V / III ratio was 2500, and a 2.5 μm thick n-type GaN contact / cladding layer doped with Si was grown.

  Next, an MQW light emitting layer composed of six layers of InGaN / GaN was grown in a nitrogen carrier gas at a substrate surface temperature of 750 ° C. and a V / III ratio of 7,500. The main carrier gas was again switched to hydrogen, the substrate surface temperature was raised to 1000 ° C., the V / III ratio was 2500, and a 0.4 μm thick p-type GaN cladding layer doped with Mg was grown. Subsequently, the substrate surface temperature was set to 750 ° C., and a p-side contact layer made of Si—InGaN having a thickness of about 3 nm was formed in a nitrogen carrier gas.

  After forming the p-side contact layer, the ammonia gas was stopped and the nitrogen gas was allowed to flow to naturally cool to room temperature, and the wafer was taken out from the metal organic vapor phase apparatus. The off-C surface substrate and the high-temperature buffer layer AlN layer were separated and separated.

  Next, the high-temperature buffer layer AlN was dissolved in a high-temperature phosphoric acid solution at about 200 ° C. to produce a flat Si—GaN growth substrate.

  A p-electrode (Ni / Au) and an n-electrode (Ti / Al / Ti / Au) are formed on each of the growth substrate layer with the p-side contact layer and the reflective layer so as to face each other, and scribing is performed. A 250 μm square chip was prepared by this method. Thus, an element having the light extraction surface side of the layer grown on the c-plane off-substrate as the p-layer side was produced.

  When the characteristics of the light-emitting element thus obtained were evaluated, the light emission wavelength of the element was 460 nm, Vf was 3.2 V, and the light emission output was 8 mW at a current of 20 mA. This value is a 380 μm square structure in which the above-described functional layer (light emitting layer) is formed on a sapphire substrate via a GaN buffer layer, an electrode is formed on the same side of the growth surface, and the structure shown in FIG. The characteristics of the chip were almost the same.

  There was no particular difference between the off angle of 0.2 degrees and 0.4 degrees.

(Example 2)
In this example, a nitride compound semiconductor device was fabricated in the same manner as in Example 1 except that the light extraction surface in Example 1 was changed to the n side instead of the p side. First, as described above, a functional layer including an Al metal layer, an AlN buffer layer, a Si-GaN growth substrate layer, an MQW light emitting layer, and the like is sequentially formed on the sapphire substrate. After peeling off from the AlN buffer layer and dissolving the AlN buffer layer, the surface excluding the portion that becomes the n-bad portion of the growth substrate layer surface is RIE, interference exposure, EB method, height 0.5 μm, A conical column with a period of 0.17 μm was produced. Next, a p-electrode (Ni / Au) and an n-electrode (Ti / Al / Ti / Au) are formed on each of the p-side contact layer and the growth substrate layer so as to face each other, and 250 μm is formed by a scribing method. A corner chip was made.

  When the characteristics of the light-emitting element thus obtained were evaluated, the light emission wavelength of the element was 460 nm, Vf was 3.2 V, and the light emission output was 24 mW at a current of 20 mA. There was no particular difference between the off angle of 0.2 degrees and 0.4 degrees.

(Example 3)
A nitride-based compound semiconductor device was fabricated in the same manner as in Example 1 except that the preflow time for forming the Al layer in Example 1 was set to 20 seconds and 60 seconds. After the formation of the light emitting layer as the functional layer, the sapphire substrate and the buffer layer were peeled off and separated.

(Comparative Example 1)
A nitride-based compound semiconductor device was produced in the same manner as in Example 1 except that no Al layer was formed in Example 1. In this case, no separation was observed between the sapphire substrate and the buffer layer.

(Comparative Example 2)
In Example 1, a nitride-based compound semiconductor device was fabricated in the same manner as in Example 1 except that a C-plane sapphire substrate was used instead of using a sapphire substrate having an off main surface. In this case, no separation was observed between the sapphire substrate and the buffer layer.

(Comparative Example 3)
In Example 1, a nitride-based compound semiconductor device was produced in the same manner as in Example 1 except that an R-plane sapphire substrate was used instead of using a sapphire substrate having a turned-off main surface. In this case, no separation was observed between the sapphire substrate and the buffer layer.

  As mentioned above, the present invention has been described in detail based on the embodiments of the invention with specific examples. It can be changed.

It is a block diagram which shows an example of the conventional light emitting element. It is a block diagram which shows an example of the conventional light emitting element. It is a figure which shows roughly the whole layer structure obtained according to the method of this invention before peeling arises in the interface of a sapphire substrate and a buffer layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light emitting element 11 Sapphire substrate 12 Low temperature buffer layer 13 n-type contact layer 14 n-type clad layer 15 Light emitting layer 15
16 p-type cladding layer 17 p-type contact layer 18 p-type electrode 19 n-type electrode 20 light-emitting element 22 growth substrate layer 24 n-type cladding layer 25 light-emitting layer 26 p-type cladding layer 27 p-type contact layer 28 p-type electrode 29 n-type Electrode 30 Layer configuration 31 Sapphire substrate 32 Al-containing metal layer 33 (High temperature) buffer layer 34 Growth substrate layer 35 Functional layer

Claims (21)

Sapphire having a principal surface off from the C surface of the sapphire substrate, a principal surface off from the R surface of the sapphire substrate on the surface including the c axis, or a principal surface off from the R surface of the sapphire substrate to the opposite side to the c axis Preparing a substrate;
Preflowing an organometallic compound containing at least aluminum to the surface of the sapphire substrate to form a metal layer made of an aluminum metal alone or an alloy of aluminum and gallium ;
Forming a buffer layer made of a nitride compound semiconductor having a composition of AlGaN on the metal layer;
Forming a growth substrate layer made of a nitride compound semiconductor on the buffer layer;
Forming a functional layer made of a nitride compound semiconductor on the growth substrate layer;
Peeling the sapphire substrate and the buffer layer through the metal layer to obtain a nitride-based compound semiconductor device including at least the growth substrate layer and the functional layer;
A method for producing a nitride-based compound semiconductor device, comprising:   2. The method for manufacturing a nitride-based compound semiconductor device according to claim 1, wherein the sapphire substrate is turned off within a range of 0.05 ° to 1 ° from the C-plane.   2. The nitride-based compound semiconductor according to claim 1, wherein the sapphire substrate is turned off in a range of 0.25 to 0.75 degrees within a plane including the c-axis from the R plane. Device manufacturing method. The method for producing a nitride-based compound semiconductor element according to any one of claims 1 to 3 , wherein the thickness of the metal layer is in the range of 1 atomic layer to 20 atomic layers. The method for producing a nitride-based compound semiconductor device according to claim 4 , wherein the thickness of the metal layer is in the range of 1 atomic layer to 5 atomic layers. 6. The method for producing a nitride-based compound semiconductor device according to claim 5 , wherein the thickness of the metal layer is in the range of 1 atomic layer to 3 atomic layers. The buffer layer and forming at temperatures above 1100 ° C., a method of manufacturing a nitride-based compound semiconductor device according to any one of claims 1-6. The method for manufacturing a nitride-based compound semiconductor device according to claim 7 , wherein the buffer layer is formed in a temperature range of 1100C to 1550C. The method for producing a nitride-based compound semiconductor device according to any one of claims 1 to 8 , wherein an aluminum content ratio relative to all group III elements in the buffer layer is 90 atomic% or more. The method for manufacturing a nitride-based compound semiconductor device according to claim 9 , wherein the buffer layer is made of AlN. Characterized by the above 0.3μm thickness of the buffer layer, a method of manufacturing a nitride-based compound semiconductor device according to any one of claims 1-10. The method for manufacturing a nitride-based compound semiconductor device according to claim 11 , wherein the buffer layer has a thickness of 1 μm to 10 μm. Characterized in that the thickness of the growth substrate layer and the above 10 [mu] m, a method of manufacturing a nitride-based compound semiconductor device according to any one of claims 1 to 12. The method for producing a nitride-based compound semiconductor device according to any one of claims 1 to 13 , wherein a film formation rate when forming the growth substrate layer is 3 µm / hour or more. 15. The method for producing a nitride-based compound semiconductor device according to claim 14 , wherein a film formation rate when forming the growth substrate layer is 100 [mu] m / hour or less. The buffer layer, characterized in that the total thickness of the growth substrate layer and the functional layer 10μm or more, a method of manufacturing a nitride-based compound semiconductor device according to any one of claims 1 to 15. 17. The method of manufacturing a nitride-based compound semiconductor device according to claim 16 , wherein a total thickness of the buffer layer, the growth substrate layer, and the functional layer is 20 μm or more. 18. The method of manufacturing a nitride-based compound semiconductor device according to claim 17 , wherein a total thickness of the buffer layer, the growth substrate layer, and the functional layer is 40 μm or more. The manufacture of the nitride-based compound semiconductor device according to any one of claims 1 to 18 , wherein the sapphire substrate and the buffer layer are separated through the metal layer by natural cooling. Method. The nitride according to any one of claims 1 to 19 , further comprising a step of removing the buffer layer after the sapphire substrate and the buffer layer are separated through the metal layer. For manufacturing a semiconductor compound semiconductor device. 21. The method according to any one of claims 1 to 20 , further comprising a step of forming electrodes on the main surface of the growth substrate layer and the main surface of the functional layer so as to face each other . A method for manufacturing a nitride compound semiconductor device.

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