III-nitride semiconductor device manufacturing apparatus and method

Abstract

To provide an apparatus and method for manufacturing a Group III nitride semiconductor device, which is intended to supply a large number of radicals to a substrate while suppressing the influence of plasma on organometallic gases and semiconductor crystals.SOLUTION: A radical transport chamber RM2 is a cavity penetrating a pBN material, and is arranged between a plasma generation chamber RM1 and a reaction chamber RM3. A first gas supply pipe 1300 has an opening inside the reaction chamber RM3, and supplies the first gas inside the reaction chamber RM3. A second gas supply pipe 1420 supplies the second gas inside the plasma generation chamber RM1. The cylindrical cavity of the radical transport chamber RM2 communicates the plasma generation chamber RM1 and the reaction chamber RM3.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technical field of the present specification relates to a manufacturing apparatus and method for a group III nitride semiconductor device using plasma. [Background technology]

[0002] In Group III nitride semiconductors, such as GaN, the band gap can be varied from 0.6 eV to 6 eV by changing the composition, and therefore Group III nitride semiconductors are used in light-emitting devices, laser diodes, photodetectors, and other devices that emit light over a wide range of wavelengths, from near infrared to deep ultraviolet.

[0003] Furthermore, Group III nitride semiconductors have high breakdown field strength and high melting points. Therefore, Group III nitride semiconductors are expected to replace GaAs-based semiconductors as materials for high-power, high-frequency, and high-temperature semiconductor devices. For this reason, HEMT elements and other devices are being researched and developed.

[0004] One method for epitaxially growing Group III nitride semiconductors is metalorganic chemical vapor deposition (MOCVD). MOCVD uses large amounts of ammonia gas. This requires the MOCVD furnace to be equipped with an ammonia removal device. The running costs of ammonia are also high. The semiconductor layer is formed by a reaction between the metalorganic gas and ammonia. For this reaction to occur, the substrate temperature must be high. A high substrate temperature makes it difficult to grow a high-quality InGaN layer with a high In concentration. Furthermore, warping is likely to occur due to the difference in thermal expansion between the growth substrate and the semiconductor layer.

[0005] Furthermore, molecular beam epitaxy (MBE) is an example of a method for epitaxially growing Group III nitride semiconductors. MBE allows Group III nitride semiconductors to be grown at low growth temperatures. However, RF-MBE, which uses a radical source, has a slow growth rate. In other words, RF-MBE is not suitable for mass production. MBE, which uses ammonia gas, requires a large amount of ammonia gas, resulting in high manufacturing costs. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-99866 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Document 1 discloses a technique for growing a Group III nitride semiconductor by supplying a first gas (metallic organo-gas) containing a Group III metal to a substrate without converting it into plasma, and supplying a second gas containing nitrogen gas to the substrate after converting it into plasma.

[0008] In the manufacturing apparatus described in Patent Document 1, the showerhead electrode is located away from the susceptor, thereby preventing charged particles in the plasma from adversely affecting the first gas and the semiconductor on the substrate. However, if the showerhead electrode is located away from the susceptor, radicals in the plasma are deactivated before reaching the susceptor. In other words, there is a trade-off between preventing the plasma from adversely affecting the organometallic gas and the semiconductor crystal and supplying a large number of radicals to the substrate.

[0009] The problem to be solved by the technology of this specification is to provide an apparatus and method for manufacturing a Group III nitride semiconductor device that is capable of supplying a large number of radicals to a substrate while suppressing the influence of plasma on metal-organic gases and semiconductor crystals. [Means for solving the problem]

[0010] The manufacturing apparatus for a Group III nitride semiconductor device according to the first aspect includes: The furnace body has a furnace body, a first gas supply pipe, a second gas supply pipe, and a cylindrical member arranged inside the furnace body, the cylindrical member having a diameter smaller than the diameter of the inner wall surface of the furnace body and not in contact with the inner wall surface of the furnace body, the inside of the furnace body has a plasma generation chamber, a reaction chamber, and a radical transport chamber located between the plasma generation chamber and the reaction chamber for transporting radicals generated in the plasma generation chamber to the reaction chamber, the plasma generation chamber has a first electrode and a charged particle capturer for capturing charged particles in the plasma, the reaction chamber has a substrate support for supporting a growth substrate; the radical transport chamber is inside the cylinder of the radical transport section and communicates with the plasma generation chamber and the reaction chamber; the first gas supply pipe has an opening that opens into the reaction chamber and at least one first gas outlet, and supplies an organometallic gas containing a Group III metal as a first gas into the reaction chamber; and the second gas supply pipe supplies a gas containing nitrogen gas as a second gas into the plasma generation chamber.

[0011] This Group III nitride semiconductor device manufacturing apparatus has a radical transport unit with a cylindrical cavity. The radical transport unit suppresses deactivation of radicals. The radical transport unit suppresses deactivation of generated radicals and also suppresses generated charged particles from reaching the substrate. Therefore, the Group III nitride semiconductor device manufactured by this manufacturing apparatus has high-quality crystallinity. [Effects of the Invention]

[0012] This specification provides an apparatus and method for manufacturing a Group III nitride semiconductor device that is capable of supplying a large number of radicals to a substrate while suppressing the influence of plasma on metalorganic gases and semiconductor crystals. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing the structure of a semiconductor wafer Wa1 according to a first embodiment. [Figure 2] 1 is a diagram showing a schematic configuration of a manufacturing apparatus 1000 according to a first embodiment. [Figure 3] FIG. 2 is a diagram showing the internal structure of a furnace body 1001 of a manufacturing apparatus 1000 according to the first embodiment. [Figure 4] FIG. 10 is a diagram showing a radical transport part RD2 in a modified example of the first embodiment. [Figure 5] FIG. 10 is a diagram showing a radical transport part RD3 in a modified example of the first embodiment. [Figure 6] FIG. 10 is a diagram showing a radical transport part RD4 in a modified example of the first embodiment. [Figure 7] 1 is a scanning electron microscope photograph showing the surface of Sample 1. [Figure 8]1 is a scanning electron microscope photograph showing a cross section of Sample 1. [Figure 9] 1 is a scanning electron microscope photograph showing the surface of Sample 2. [Figure 10] 1 is a scanning electron microscope photograph showing a cross section of Sample 2. [Figure 11] 1 is a scanning electron microscope photograph showing the surface of Sample 3. [Figure 12] 1 is a scanning electron microscope photograph showing a cross section of Sample 3. [Figure 13] 1 is a scanning electron microscope photograph showing the surface of Sample 4. [Figure 14] 1 is a scanning electron microscope photograph showing a cross section of Sample 4. DETAILED DESCRIPTION OF THE INVENTION

[0014] Specific embodiments of a manufacturing apparatus and method for a Group III nitride semiconductor device will be described below with reference to the drawings.

[0015] (First embodiment)

[0016] 1.Semiconductor wafers FIG. 1 is a diagram showing the structure of a semiconductor wafer Wa1 according to the first embodiment. The semiconductor wafer Wa1 has a substrate Sa1 and a semiconductor layer F1. The substrate Sa1 is a growth substrate. The semiconductor layer F1 is a single-crystal semiconductor layer made of a Group III nitride semiconductor. In this way, the semiconductor wafer Wa1 is formed by epitaxially growing a Group III nitride semiconductor on the main surface of the wafer.

[0017] 2. III-nitride semiconductor device manufacturing equipment 2 is a schematic diagram of a manufacturing apparatus 1000 for a Group III nitride semiconductor device according to the first embodiment. The manufacturing apparatus 1000 generates plasma from a mixed gas containing nitrogen gas and hydrogen gas, supplies the plasma product to a growth substrate, and also supplies an organometallic gas containing a Group III metal to the growth substrate without generating plasma.

[0018] The manufacturing apparatus 1000 includes a furnace body 1001, a shower head electrode 1100, a susceptor 1200, a heater 1210, a first gas supply pipe 1300, a gas introduction chamber 1410, a second gas supply pipe 1420, a charged particle capture unit 1500, an RF power supply 1600, a matching box 1610, a first gas supply unit 1710, a second gas supply unit 1810, gas containers 1910, 1920, and 1930, constant temperature baths 1911, 1921, and 1931, mass flow controllers 1720, 1820, 1830, 1840, and 1850, and a radical transport unit RD1. The manufacturing apparatus 1000 also includes an exhaust port (not shown).

[0019] The showerhead electrode 1100 is a first electrode to which a periodic potential is applied. The showerhead electrode 1100 is made of, for example, stainless steel. Of course, other metals may also be used. The showerhead electrode 1100 is a flat electrode. The showerhead electrode 1100 has a plurality of through-holes (not shown) penetrating from the front surface to the back surface. These through-holes communicate with the gas introduction chamber 1410 and the second gas supply pipe 1420. Therefore, the second gas supplied from the gas introduction chamber 1410 to the inside of the furnace body 1001 is suitably converted into plasma. The showerhead electrode 1100 is disposed farther from the susceptor 1200 than the through-hole of the first gas supply pipe 1300.

[0020] The susceptor 1200 is a substrate support portion for supporting the substrate Sa1. The material of the susceptor 1200 is, for example, graphite. Alternatively, other conductive materials may be used. Here, the substrate Sa1 is a growth substrate for growing a Group III nitride semiconductor.

[0021] The first gas supply pipe 1300 is for supplying a first gas to the susceptor 1200. In practice, the first gas is supplied to the substrate Sa1 supported by the susceptor 1200. Here, the first gas is an organometallic gas containing a Group III metal. The first gas may also contain other carrier gases. The first gas supply pipe 1300 has a ring-shaped ring portion 1310. The ring portion 1310 of the first gas supply pipe 1300 has 12 through-holes (not shown) formed inside the ring portion 1310. These through-holes are first gas outlets from which the first gas is ejected. Therefore, the first gas is ejected toward the inside of the ring portion 1310. As will be described later, the first gas supply pipe 1300 is located away from a plasma generation region.

[0022] The second gas supply pipe 1420 is used to supply a second gas to the susceptor 1200. In practice, the second gas is introduced into the gas introduction chamber 1410 and the furnace body 1001, and is also supplied to the substrate Sa1 supported by the susceptor 1200. The second gas supply pipe 1420 supplies the second gas into the furnace body 1001. Here, the second gas supplied by the second gas supply pipe 1420 is a gas containing at least nitrogen gas. The second gas supply pipe 1420 may supply a mixed gas of nitrogen gas and hydrogen gas as the second gas. The gas introduction chamber 1410 temporarily stores the mixed gas of nitrogen gas and hydrogen gas and supplies the mixed gas to the through-holes of the showerhead electrode 1100.

[0023] The charged particle capture unit 1500 is for capturing charged particles. The charged particle capture unit 1500 is made of, for example, stainless steel. Of course, other metals may also be used. The charged particle capture unit 1500 is disposed between the shower head electrode 1100 and the susceptor 1200. Therefore, as will be described later, charged particles generated in the plasma generation region can be prevented from moving toward the growth substrate Sa1 supported by the susceptor 1200. Furthermore, the charged particle capture unit 1500 is disposed between the shower head electrode and the ring portion 1310 of the first gas supply pipe 1300. Therefore, charged particles can be prevented from colliding with organometallic molecules containing a Group III metal ejected from the first gas supply pipe 1300.

[0024] The furnace body 1001 accommodates at least the showerhead electrode 1100, the susceptor 1200, the ring portion 1310 of the first gas supply pipe 1300, and the charged particle capture unit 1500. The furnace body 1001 is made of, for example, stainless steel. The furnace body 1001 may be made of a conductive material other than those mentioned above.

[0025] The heater 1210 heats the substrate Sa1 supported by the susceptor 1200 via the susceptor 1200.

[0026] Mass flow controllers 1720, 1820, 1830, and 1840 are used to control the flow rates of the respective gases. Thermostatic baths 1911, 1921, and 1931 are filled with antifreeze solutions 1912, 1922, and 1932. Gas containers 1910, 1920, and 1930 are containers for storing organometallic gases containing Group III metals. Gas containers 1910, 1920, and 1930 store trimethylgallium, trimethylindium, and trimethylaluminum, respectively. Of course, organometallic gases containing other Group III metals, such as triethylgallium, may also be used.

[0027] The furnace body 1001, the charged particle trapping section 1500, and the first gas supply pipe 1300 are conductive members, and are all grounded.

[0028] The RF power supply 1600 is a potential applying unit that applies a periodic high frequency potential to the shower head electrode 1100 .

[0029] 3. Radical transporter 3-1. Structure of the radical transporter 3 is a diagram showing the internal structure of the furnace body 1001 of the manufacturing apparatus 1000 in the first embodiment. The radical transport part RD1 is made of pBN and has a cylindrical cavity. The radical transport part RD1 is located between the shower head electrode 1100 and the through-hole of the first gas supply pipe 1300. The furnace body 1001 has a plasma generation chamber RM1, a radical transport chamber RM2, and a reaction chamber RM3.

[0030] The plasma generation chamber RM1 is a chamber for generating plasma and includes a shower head electrode 1100 and a charged particle capture unit 1500.

[0031] The radical transport chamber RM2 is a chamber for transporting radicals generated in the plasma generation chamber RM1 to the reaction chamber RM3. The radical transport chamber RM2 is surrounded by the radical transport unit RD1. The radical transport unit RD1 is made of pBN and has a cylindrical cavity. This cylindrical cavity corresponds to the radical transport chamber RM2. This cylindrical cavity penetrates from the plasma generation chamber RM1 to the reaction chamber RM3. In other words, this cylindrical cavity penetrates from the shower head electrode 1100 to the susceptor 1200. The radical transport chamber RM2 is located between the plasma generation chamber RM1 and the reaction chamber RM3. The cylindrical cavity of the radical transport chamber RM2 connects the plasma generation chamber RM1 and the reaction chamber RM3. The cylindrical cavity of the radical transport chamber RM2 is located between the charged particle capture unit 1500 of the plasma generation chamber RM1 and the opening of the first gas supply pipe 1300 of the reaction chamber RM3.

[0032] The reaction chamber RM3 is a chamber for growing a semiconductor on the substrate Sa1. The reaction chamber RM3 has a susceptor 1200.

[0033] The first gas supply pipe 1300 has an opening in the reaction chamber RM3 and supplies the first gas into the reaction chamber RM3.

[0034] The second gas supply pipe 1420 supplies a second gas to the inside of the plasma generation chamber RM1.

[0035] The radical transporter RD1 is a cylindrical part made of pBN (pyrolytic boron nitride). The radical transporter RD1 is disposed between the shower head electrode 1100 and the susceptor 1200. The radical transporter RD1 is also disposed between the charged particle capture part 1500 and the through-hole of the ring part 1310 of the first gas supply pipe 1300.

[0036] The radical transporter RD1 is a cylindrical section for transmitting radicals among the plasma products generated in the plasma generation region. The length of the cavity in the radical transporter RD1 that penetrates the radical transporter RD1 is, for example, 20 mm or more and 1000 mm or less, and more preferably 30 mm or more and 300 mm or less. The length of the cavity in the radical transporter RD1 that penetrates the radical transporter RD1 is, for example, 0.5 times or more and 200 times or less the inner diameter of the cavity, and preferably 1 time or more and 100 times or less. It may be 1.2 times or more and 50 times or less.

[0037] 3-2. Relationship between the radical transport region and the plasma generation region The area directly below the showerhead electrode 1100 is a plasma generation region. The plasma generated in the plasma generation region contains plasma products such as cations, electrons, radicals, and ultraviolet rays. The charged particle capture unit 1500 captures cations and electrons and does not allow ultraviolet rays to pass through to the susceptor 1200. The plasma generation chamber RM1 has a plasma generation region, but the radical transport chamber RM2 of the radical transport unit RD1 does not have a plasma generation region.

[0038] Therefore, radicals and rare gases among the plasma products generated in the plasma generation region enter the radical transport part RD1. The plasma gas contains nitrogen gas, hydrogen gas, and rare gases. Therefore, radicals derived from nitrogen atoms and hydrogen atoms, and rare gases, etc. enter the radical transport part RD1. Since the radical transport part RD1 is made of pBN, it suppresses the deactivation of radicals. The radicals that pass through the radical transport part RD1 head toward the susceptor 1200.

[0039] The radicals that have passed through the radical transporter RD1 react with the group III metal on the surface of the substrate Sa1 on the susceptor 1200 to produce a group III nitride semiconductor.

[0040] 3-3.Effect of radical transporter The radical transport part RD1 transports radicals generated by the plasma toward the susceptor 1200 so as to prevent deactivation as much as possible.

[0041] In order to supply a large number of radicals to the susceptor 1200, it is possible to shorten the distance between the showerhead electrode 1100 and the susceptor 1200 without providing the radical transporter RD1. However, in this case, there is a risk that cations and electrons other than radicals may reach the substrate Sa1 on the susceptor 1200. If these cations and electrons reach the substrate Sa1, the crystallinity of the semiconductor crystal will deteriorate.

[0042] For this reason, the radical transport unit RD1 increases the distance between the plasma generation region and the through-hole of the ring portion 1310 of the first gas supply pipe 1300, and also suppresses the deactivation of radicals. This is to suppress the conversion of the organometallic gas that is not converted into plasma after the charged particle capture unit 1500 captures the charged particles.

[0043] In this way, in order to form a semiconductor film, in order to convert one gas into plasma and not the other gas into plasma, it is necessary to provide the radical transport section RD1 downstream of the charged particle capture section 1500 and upstream of the through hole in the ring section 1310 of the first gas supply pipe 1300.

[0044] The charged particle capture unit 1500 captures charged particles. However, the charged particle capture unit 1500 does not necessarily capture all charged particles. The existence of the radical transport chamber RM2 over a certain length further reduces the trace amount of charged particles among the particles heading toward the reaction chamber RM3.

[0045] 4. Operation of the manufacturing equipment 4-1.Plasma generation The furnace body 1001, the charged particle trapping unit 1500, and the first gas supply pipe 1300 are all conductive members and are grounded. Therefore, when a potential is applied to the showerhead electrode 1100, a voltage is applied between the showerhead electrode 1100 and the furnace body 1001, the charged particle trapping unit 1500, and the first gas supply pipe 1300. It is believed that a discharge occurs between the showerhead electrode 1100 and at least one of the furnace body 1001, the charged particle trapping unit 1500, and the first gas supply pipe 1300. A high-frequency, high-intensity electric field is formed directly below the showerhead electrode 1100. Therefore, the position directly below the showerhead electrode 1100 is a plasma generation region.

[0046] The second gas, i.e., a mixed gas of nitrogen gas and hydrogen gas, is converted into plasma in the plasma generation region. Plasma products are generated in the plasma generation region. The plasma products in this case include nitrogen radicals, hydrogen radicals, hydrogen nitride-based compounds, electrons, and other ions. The hydrogen nitride-based compounds include NH, NH2, NH3, and their excited states, as well as other ions.

[0047] The charged particle capture unit 1500 captures positive ions and electrons from among the plasma products generated inside the plasma generation chamber RM1. The charged particle capture unit 1500 is made up of metal meshes stacked and offset from one another. This allows the charged particle capture unit 1500 to reflect or absorb ultraviolet rays. Consequently, neutral particles from the plasma generated inside the plasma generation chamber RM1 move to the radical transport chamber RM2. Here, the neutral particles include radicals and rare gases.

[0048] The radical transport chamber RM2 supplies radicals to the substrate Sa1 without substantially deactivating the radicals.

[0049] 4-2. Manufacturing equipment conditions Table 1 shows the manufacturing conditions for the manufacturing apparatus 1000. The numerical ranges listed in Table 1 are merely guidelines and do not necessarily have to be these numerical ranges. The RF power is in the range of 100 W or more and 1000 W or less. The frequency of the periodic potential applied to the shower head electrode 1100 by the RF power supply 1600 is in the range of 30 MHz or more and 300 MHz or less. The substrate temperature is in the range of 400° C. or more and 900° C. or less. The substrate temperature may also be room temperature or higher. The internal pressure of the manufacturing apparatus 1000 is in the range of 1 Pa or more and 10,000 Pa or less.

[0050] [Table 1] RF power 100W or more 1000W or less Frequency: 30MHz or more, 300MHz or less Substrate temperature 400℃ or more 900℃ or less Internal pressure: 1 Pa or more, 10,000 Pa or less

[0051] 5. Semiconductor wafer manufacturing method 5-1. Cleaning the board Here, a method for manufacturing a semiconductor wafer using the manufacturing apparatus 1000 of the first embodiment will be described. First, a substrate Sa1 is prepared. For example, a c-plane sapphire substrate can be used as the substrate Sa1. Other substrates may also be used. The substrate Sa1 is placed inside the manufacturing apparatus 1000, and the substrate temperature is raised to about 400°C while supplying hydrogen gas. This reduces the surface of the substrate Sa1 and cleans the surface of the substrate Sa1. The substrate temperature may be higher.

[0052] 5-2. Semiconductor layer formation process Next, the RF power supply 1600 is turned on. Then, a mixed gas of nitrogen gas and hydrogen gas is supplied from the second gas supply pipe 1420. The mixed gas supplied into the furnace body 1001 through the through-holes in the showerhead electrode 1100 is converted into plasma directly below the showerhead electrode 1100. Therefore, a plasma generation region is generated directly below the showerhead electrode 1100. At this time, nitrogen radicals and hydrogen radicals are generated. It is believed that the nitrogen radicals and hydrogen radicals then react to generate hydrogen nitride-based compounds. Electrons and other charged particles are also generated.

[0053] The radical mixture gas containing nitrogen radicals, hydrogen radicals, hydrogen nitride-based compounds, electrons, and other charged particles is then sent toward the substrate Sa1. This radical mixture gas is generated directly below the showerhead electrode 1100. Because the distance from the showerhead electrode 1100 to the substrate Sa1 is sufficiently large, charged particles such as electrons and ions in the radical mixture gas are unlikely to reach the substrate Sa1. Furthermore, charged particles are easily captured by the charged particle capture unit 1500. Therefore, it is believed that in addition to nitrogen radicals and hydrogen radicals, hydrogen nitride-based compounds are also supplied toward the substrate Sa1. Compared to ordinary ammonia, the reactivity of these nitrogen radicals and hydrogen nitride-based compounds is higher. As a result, a semiconductor layer can be epitaxially grown at a lower temperature than conventional methods.

[0054] Meanwhile, a metalorganic gas of a group III metal is supplied from the ring portion 1310 of the first gas supply pipe 1300. Examples of such gases include trimethylgallium, trimethylindium, and trimethylaluminum. These gases are entrained in the radical mixture gas directed toward the substrate Sa1 and are supplied to the substrate Sa1. The metalorganic gas of a group III metal is supplied to the substrate Sa1 without being converted into plasma.

[0055] As described above, in the first embodiment, a mixed gas containing nitrogen gas and hydrogen gas is converted into plasma, and radicals in the plasma-converted gas are passed through the interior of the pBN cylindrical portion before being supplied to the growth substrate. At the same time, an organometallic gas containing a Group III metal is supplied to the growth substrate without being converted into plasma and without being passed through the interior of the pBN cylindrical portion, thereby growing a Group III nitride semiconductor on the growth substrate.

[0056] 5-3.Semiconductor wafers In this way, a Group III nitride semiconductor is epitaxially grown on the primary surface of the substrate Sa1, thereby producing a semiconductor wafer. The Group III nitride semiconductor in this semiconductor wafer has good crystallinity.

[0057] 6. Effects of the First Embodiment The manufacturing apparatus 1000 of the first embodiment has a plasma generation chamber RM1, a radical transport chamber RM2, and a reaction chamber RM3. Most of the charged particles in the plasma generated in the plasma generation chamber RM1 are captured by the charged particle capture unit 1500, and the remaining charged particles are reduced in the radical transport chamber RM2. As a result, radicals and compounds derived from nitrogen atoms and hydrogen atoms in the plasma generated in the plasma generation chamber RM1, as well as the rare gas, pass through the radical transport chamber RM2 and reach the reaction chamber RM3. In the reaction chamber RM3, the radicals that have passed through the radical transport chamber RM2 react with the first gas supplied from the through-holes in the ring portion 1310 of the first gas supply pipe 1300 on the surface of the substrate Sa1. As a result, a Group III nitride semiconductor is grown on the substrate Sa1.

[0058] In this way, radicals or rare gases in the plasma generated in the plasma generation chamber RM1 reach the substrate Sa1, and charged particles hardly reach the reaction chamber RM3, resulting in good crystallinity of the semiconductor grown on the substrate Sa1.

[0059] Furthermore, since many radicals reach the substrate Sa1, the semiconductor film formation rate is high.

[0060] 7. Variations 7-1. Shape of the radical transporter FIG. 4 is a diagram showing a radical transport unit RD2 in a modified example of the first embodiment. The upper view of FIG. 4 shows the radical transport unit RD2 as viewed from the shower head electrode 1100 side. The lower view of FIG. 4 shows the radical transport unit RD2 as viewed from a direction perpendicular to the upper view of FIG. 4. As shown in FIG. 4, the radical transport unit RD2 has multiple cavities RD2a extending from the plasma generation chamber RM1 to the reaction chamber RM3. The cavities RD2a have a cylindrical inner surface shape. In this case, the radical transport chamber has multiple cavities RD2a. The length of the cavities RD2a penetrating the radical transport unit RD2 is, for example, 0.5 to 200 times the inner diameter of the cavities RD2a. Preferably, it is 1 to 100 times. It may be 1.2 to 50 times.

[0061] Figure 5 is a diagram showing the radical transport unit RD3 in a modified example of the first embodiment. As shown in Figure 5, the radical transport unit RD3 has multiple cavities RD3a, RD3b, RD3c, RD3d, and RD3e that extend from the plasma generation chamber RM1 to the reaction chamber RM3. The central cavity RD3a has a cylindrical inner surface. The other cavities RD3b, RD3c, RD3d, and RD3e are cylindrical cavities sandwiched between a cylindrical inner surface and a cylindrical outer surface that are concentrically arranged with respect to cavity RD3a. The radical transport chamber has multiple cavities arranged concentrically.

[0062] Fig. 6 is a diagram showing a radical transporter RD4 in a modified example of the first embodiment. As shown in Fig. 6, the radical transporter RD4 has multiple cavities RD4a that extend from the plasma generation chamber RM1 to the reaction chamber RM3. The cavities RD4a have an inner shape of a square tube. In Fig. 6, the square tubes are arranged in a square lattice pattern.

[0063] 7-2.Material of radical transport part The material of the radical transporter RD1 may be, for example, borosilicate glass, Si, Cu, Ti, Al, AlN, alumina, or Si3N4.

[0064] 7-3.Through hole in the ring In the first embodiment, the first gas supply pipe 1300 has a through-hole inside the ring portion 1310. However, the position of this through-hole may be inside the ring and point downward. The angle formed by the plane including the ring portion 1310 and the direction of the opening of the through-hole is, for example, 45°. This angle may be changed, for example, within a range of 0° to 60°. Of course, this angle also depends on the diameter of the ring portion 1310 and the distance between the ring portion 1310 and the susceptor 1200. Furthermore, the number of through-holes may be one or more. Of course, it is preferable that the through-holes are formed at equal intervals in the ring portion 1310.

[0065] 7-4. Pulse voltage The RF power supply 1600 may repeatedly apply a pulsed voltage to the showerhead electrode 1100 .

[0066] 7-5. Semiconductor Devices A semiconductor device may be manufactured by forming a semiconductor layer on the semiconductor wafer Wa1 and forming electrodes thereon.

[0067] 7-6. Combinations The above modifications may be freely combined. [Example]

[0068] A. Experiment 1 1. Sample production 1-1. Sample 1 Sample 1 was manufactured as follows. GaN was grown using a manufacturing apparatus 1000 equipped with a radical transport chamber RM2. A 10 mm square GaN / Si substrate with a GaN thickness of 2.5 μm was used as the growth substrate. A mixture of nitrogen gas at 1500 sccm and hydrogen gas at 1500 sccm was used as the second gas. TMG was used as the first gas. H2 was used as the carrier gas. The flow rate of H2 was 20 sccm, and the flow rate of TMG was 2.4 sccm. The internal pressure of the manufacturing apparatus 1000 was 300 Pa. After the GaN / Si substrate was heated to 800°C, the RF power supply 1600 applied 600 W to the showerhead electrode 1100. The film formation time was 20 minutes.

[0069] 1-2. Sample 2 Sample 2 was manufactured by changing some of the manufacturing conditions of Sample 1. Sample 2 was manufactured using an apparatus in which the radical transport unit RD1 was removed from manufacturing apparatus 1000. The flow rate of nitrogen gas was 750 sccm. The flow rate of hydrogen gas was 250 sccm. No carrier gas was used. The flow rate of TMG was 1.2 sccm. The film formation time was 2 hours.

[0070] The differences between Sample 1 and Sample 2 are shown in Table 2.

[0071] [Table 2] Sample 1 with radical transporter (pBN) Sample 2: No radical transporter (pBN)

[0072] 2. Micrographs Figure 7 is a scanning electron microscope photograph showing the surface of Sample 1. As shown in Figure 7, the surface of Sample 1 is smooth.

[0073] Figure 8 is a scanning electron microscope photograph showing a cross section of Sample 1. As shown in Figure 8, the surface of Sample 1 is flat. As can be seen from the photograph, the crystallinity of the GaN is good.

[0074] Fig. 9 is a scanning electron microscope photograph showing the surface of Sample 2. As shown in Fig. 9, the surface of Sample 2 is somewhat rough.

[0075] 10 is a scanning electron microscope photograph showing a cross section of Sample 2. As shown in FIG. 10, the surface of Sample 2 has minute irregularities. The crystallinity of the GaN in Sample 2 is inferior to that of the GaN in Sample 1.

[0076] 3. Film deposition speed The deposition rate for Sample 1 was 1.7 μm / h. The deposition rate for Sample 2 was 0.45 μm / h. The deposition rate for Sample 1 was more than three times that of Sample 2.

[0077] B. Experiment 2 1. Sample production 1-1. Sample 3 Sample 3 was fabricated as follows. GaN was grown using a manufacturing apparatus 1000 equipped with a radical transport chamber RM2. A bulk GaN substrate measuring 10 mm square and with a GaN thickness of 350 μm was used as the growth substrate. After the bulk GaN substrate was heated to 800°C, a mixed gas of 1500 sccm of nitrogen gas and 1500 sccm of hydrogen gas was supplied as the second gas. TMG was used as the first gas. H2 was used as the carrier gas. The flow rate of H2 was 20 sccm, and the flow rate of TMG was 2.4 sccm. The internal pressure of the manufacturing apparatus 1000 was 300 Pa. The power applied to the showerhead electrode 1100 by the RF power supply 1600 was 600 W. The film formation time was 10 minutes.

[0078] Next, GaN was pulse-grown on the sample with GaN grown on the bulk GaN substrate. The internal pressure was 150 Pa. The nitrogen gas flow rate was set to 1500 sccm, and the nitrogen gas was converted into plasma and supplied to the GaN. No hydrogen gas was supplied. The first period was 5 seconds, and the second period was 10 seconds, and these were repeated. The output W1 during the first period was 600 W. The output W2 during the second period was 300 W. TMG was supplied during the first period. H2 was used as the carrier gas. The H2 flow rate was 20 sccm, and the TMG flow rate was 2.4 sccm. TMG was not supplied during the second period. The film formation time was 2 hours.

[0079] 1-2. Sample 4 Sample 4 was produced by changing some of the manufacturing conditions for Sample 3. Sample 4 was produced using a manufacturing apparatus 1000 with the radical transport unit RD1 removed. A 10 mm square GaN / Si substrate with a GaN thickness of 2.5 μm was used as the growth substrate. After the GaN / Si substrate was heated to 800°C, a mixed gas of 750 sccm of nitrogen gas and 250 sccm of hydrogen gas was supplied as the second gas. TMG was used as the first gas. No carrier gas was used. The flow rate of TMG was 1.2 sccm. The internal pressure of the manufacturing apparatus 1000 was 300 Pa. The power applied to the showerhead electrode 1100 by the RF power supply 1600 was 700 W. The film formation time was 1 hour.

[0080] Next, a mixed gas of 750 sccm of nitrogen gas and 250 sccm of hydrogen gas was turned into plasma and supplied to the GaN. The internal pressure was kept at 300 Pa.

[0081] Next, GaN was pulse-grown on the sample with GaN grown on the bulk GaN substrate. A mixed gas of 750 sccm nitrogen gas and 250 sccm hydrogen gas was generated as a plasma and supplied to the GaN. The first period was 18 seconds, and the second period was 1 second, and these were repeated. The output W1 during the first period was 700 W. The output W2 during the second period was 400 W. TMG was supplied at 1.2 sccm during the first period. No carrier gas was used. No TMG was supplied during the second period. The film growth time was 2 hours.

[0082] The differences between Sample 3 and Sample 4 are shown in Table 3.

[0083] [Table 3] Sample 3: Radical transporter (pBN) included Sample 4: No radical transporter (pBN)

[0084] 2. Micrographs Fig. 11 is a scanning electron microscope photograph showing the surface of Sample 3. As shown in Fig. 11, the surface of Sample 3 is smooth.

[0085] Figure 12 is a scanning electron microscope photograph showing the cross section of Sample 3. As shown in Figure 12, the surface of Sample 3 is flat. The thickness of the continuously grown GaN was 1.3 μm. The thickness of the pulsed grown GaN was 1.4 μm.

[0086] Fig. 13 is a scanning electron microscope photograph showing the surface of Sample 4. As shown in Fig. 13, the surface of Sample 4 is somewhat rough.

[0087] Fig. 14 is a scanning electron microscope photograph showing a cross section of Sample 4. As shown in Fig. 14, the surface of Sample 4 has minute irregularities.

[0088] 3. Film deposition speed The deposition rate of pulse growth for Sample 3 was 0.75 μm / h, and the deposition rate of pulse growth for Sample 4 was 0.03 μm / h.

[0089] (Addendum) A first aspect of the present invention relates to an apparatus for manufacturing a Group III nitride semiconductor device, and the apparatus includes a first electrode, a substrate support for supporting a growth substrate, a first gas supply pipe for supplying a first gas to the substrate support, a second gas supply pipe for supplying a second gas to the substrate support, and a radical transport unit having a cylindrical cavity. The first gas supply pipe has at least one first gas outlet and supplies an organometallic gas containing a Group III metal as the first gas. The second gas supply pipe supplies a gas containing nitrogen gas as the second gas. The first electrode is located farther from the substrate support than the first gas outlet of the first gas supply pipe. The radical transport unit is located between the first electrode and the first gas outlet of the first gas supply pipe.

[0090] A second aspect of the present invention provides an apparatus for manufacturing a Group III nitride semiconductor device, comprising: a plasma generation chamber, a reaction chamber, and a radical transport chamber for transporting radicals generated in the plasma generation chamber to the reaction chamber. The plasma generation chamber comprises a first electrode and a charged particle capture unit for capturing charged particles in the plasma. The reaction chamber comprises a substrate support unit. The radical transport chamber is a cylindrical cavity in the radical transport unit and is disposed between the plasma generation chamber and the reaction chamber. A first gas supply pipe has an opening in the reaction chamber and supplies a first gas to the reaction chamber. A second gas supply pipe supplies a second gas to the plasma generation chamber. The radical transport chamber communicates with the plasma generation chamber and the reaction chamber.

[0091] In the third aspect of the apparatus for manufacturing a Group III nitride semiconductor device, the radical transport chamber is disposed between the charged particle capture unit of the plasma generation chamber and the opening of the first gas supply pipe of the reaction chamber.

[0092] In the fourth aspect of the apparatus for manufacturing a Group III nitride semiconductor device, the radical transport chamber has a plurality of cavities.

[0093] In the apparatus for manufacturing a Group III nitride semiconductor device according to the fifth aspect, the radical transport chamber has a plurality of cavities arranged concentrically.

[0094] In the sixth aspect of the apparatus for manufacturing a Group III nitride semiconductor device, the radical transport section is made of any one of pBN, borosilicate glass, Si, Cu, Ti, Al, AlN, alumina, and Si3N4.

[0095] In the method for manufacturing a Group III nitride semiconductor device according to the seventh aspect, a mixed gas containing nitrogen gas and hydrogen gas is converted into plasma, and radicals in the plasmatized gas are passed through a cylindrically hollow radical transporter made of pBN before being supplied to a growth substrate, while an organometallic gas containing a Group III metal is supplied to the growth substrate without being converted into plasma and without being passed through the hollow radical transporter, thereby growing a Group III nitride semiconductor on the growth substrate. [Explanation of symbols]

[0096] 1000…Manufacturing equipment 1001...furnace body 1100...Shower head electrode 1200...Susceptor 1210…heater 1300...First gas supply pipe 1420...Second gas supply pipe 1500...Charged particle capture unit 1600...RF power supply 1610…Matching box

Claims

1. In a manufacturing apparatus for a Group III nitride semiconductor device, The furnace body, a first gas supply pipe; a second gas supply pipe; A radical transport part which is a cylindrical member arranged inside the furnace body, has a cylindrical shape with a diameter smaller than the diameter of the inner wall surface of the furnace body, and does not contact the inner wall surface of the furnace body; and The inside of the furnace body is a plasma generation chamber; A reaction chamber; a radical transport chamber located between the plasma generation chamber and the reaction chamber for transporting radicals generated in the plasma generation chamber to the reaction chamber, the plasma generation chamber has a first electrode and a charged particle capture unit that captures charged particles in the plasma; the reaction chamber has a substrate support for supporting a growth substrate; the radical transport chamber is located inside the cylinder of the radical transport unit and communicates with the plasma generation chamber and the reaction chamber; the first gas supply pipe has an opening that opens into the reaction chamber and at least one first gas outlet, and supplies an organometallic gas containing a Group III metal as a first gas into the reaction chamber; The second gas supply pipe supplies a gas containing nitrogen gas as a second gas into the plasma generation chamber.

2. The manufacturing apparatus for a Group III nitride semiconductor device according to claim 1, An apparatus for manufacturing a Group III nitride semiconductor device, wherein the axial length of the radical transport section is 0.5 to 200 times the inner diameter of the radical transport section.

3. In the manufacturing apparatus for a Group III nitride semiconductor device according to claim 1 or claim 2, The apparatus for manufacturing a Group III nitride semiconductor device, wherein the axial length of the radical transport section is 20 mm or more and 1000 mm or less.

4. 4. The apparatus for manufacturing a Group III nitride semiconductor device according to claim 1, The radical transport chamber comprises: Having multiple cavities A manufacturing apparatus for a group III nitride semiconductor device comprising:

5. 4. The apparatus for manufacturing a Group III nitride semiconductor device according to claim 1, The radical transport chamber comprises: Having multiple cavities arranged concentrically A manufacturing apparatus for a group III nitride semiconductor device comprising:

6. 6. The apparatus for manufacturing a Group III nitride semiconductor device according to claim 1, The material of the radical transport part is pBN, borosilicate glass, Si, Cu, Ti, Al, AlN, alumina, Si ３ N ４ Either A manufacturing apparatus for a group III nitride semiconductor device comprising:

7. A mixed gas containing nitrogen gas and hydrogen gas is converted into plasma, The radicals in the plasma gas are passed through a cylindrically hollow pBN radical transporter and then supplied to the growth substrate. supplying an organometallic gas containing a Group III metal to the growth substrate without converting it into plasma and without passing it through the cavity of the radical transport section; growing a group III nitride semiconductor on said growth substrate; Including, A method for manufacturing a Group III nitride semiconductor device, wherein the diameter of the radical transport section is made smaller than the diameter of the inner wall surface of the furnace body.

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