WO2015068475A1 - 炭化珪素半導体装置およびその製造方法 - Google Patents
炭化珪素半導体装置およびその製造方法 Download PDFInfo
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- WO2015068475A1 WO2015068475A1 PCT/JP2014/074710 JP2014074710W WO2015068475A1 WO 2015068475 A1 WO2015068475 A1 WO 2015068475A1 JP 2014074710 W JP2014074710 W JP 2014074710W WO 2015068475 A1 WO2015068475 A1 WO 2015068475A1
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- Prior art keywords
- silicon carbide
- sodium
- main surface
- layer
- intermediate substrate
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- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 367
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 365
- 239000004065 semiconductor Substances 0.000 title claims abstract description 109
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 87
- 239000000758 substrate Substances 0.000 claims abstract description 491
- 238000000034 method Methods 0.000 claims abstract description 112
- 238000012360 testing method Methods 0.000 claims abstract description 42
- 239000011734 sodium Substances 0.000 claims description 437
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 418
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- 238000000137 annealing Methods 0.000 claims description 114
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 72
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 72
- 229910052710 silicon Inorganic materials 0.000 claims description 72
- 239000010703 silicon Substances 0.000 claims description 72
- 229910052799 carbon Inorganic materials 0.000 claims description 68
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 52
- 239000011229 interlayer Substances 0.000 claims description 50
- 238000010438 heat treatment Methods 0.000 claims description 34
- 239000000377 silicon dioxide Substances 0.000 claims description 26
- 235000012239 silicon dioxide Nutrition 0.000 claims description 26
- NFFIWVVINABMKP-UHFFFAOYSA-N methylidynetantalum Chemical compound [Ta]#C NFFIWVVINABMKP-UHFFFAOYSA-N 0.000 claims description 24
- 229910003468 tantalcarbide Inorganic materials 0.000 claims description 24
- 238000009413 insulation Methods 0.000 abstract description 7
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- 210000000746 body region Anatomy 0.000 description 21
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 11
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- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 6
- 229910052698 phosphorus Inorganic materials 0.000 description 6
- 239000011574 phosphorus Substances 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
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- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
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- 238000010521 absorption reaction Methods 0.000 description 3
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- 125000004436 sodium atom Chemical group 0.000 description 3
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- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 2
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical compound [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
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- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 description 2
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- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 229910010038 TiAl Inorganic materials 0.000 description 1
- 229910008484 TiSi Inorganic materials 0.000 description 1
- HIVGXUNKSAJJDN-UHFFFAOYSA-N [Si].[P] Chemical compound [Si].[P] HIVGXUNKSAJJDN-UHFFFAOYSA-N 0.000 description 1
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- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
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- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910021334 nickel silicide Inorganic materials 0.000 description 1
- RUFLMLWJRZAWLJ-UHFFFAOYSA-N nickel silicide Chemical compound [Ni]=[Si]=[Ni] RUFLMLWJRZAWLJ-UHFFFAOYSA-N 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
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- 235000013842 nitrous oxide Nutrition 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
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- 230000001737 promoting effect Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
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- 239000010936 titanium Substances 0.000 description 1
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- 238000007740 vapor deposition Methods 0.000 description 1
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Definitions
- the present invention relates to a silicon carbide semiconductor device and a method for manufacturing the same, and more particularly to a silicon carbide semiconductor device capable of reducing fluctuations in threshold voltage and a method for manufacturing the same.
- silicon carbide has been increasingly adopted as a material constituting semiconductor devices in order to enable higher breakdown voltage, lower loss, and use in high-temperature environments.
- Silicon carbide is a wide band gap semiconductor having a larger band gap than silicon that has been widely used as a material for forming semiconductor devices. Therefore, by adopting silicon carbide as a material constituting the semiconductor device, it is possible to achieve a high breakdown voltage and a low on-resistance of the semiconductor device.
- a semiconductor device that employs silicon carbide as a material has an advantage that a decrease in characteristics when used in a high temperature environment is small as compared with a semiconductor device that employs silicon as a material.
- MOSFET Metal Oxide Semiconductor Field Effect Transistor
- IGBT Insulated Gate Bipolar Transistor
- Non-patent Document 1 discloses a method of annealing a silicon carbide substrate on which a gate oxide film is formed in a hydrogen atmosphere in order to reduce the fluctuation of the threshold voltage.
- the threshold voltage fluctuation is reduced at the stage where the gate electrode is formed on the substrate, but it is considered that the threshold voltage fluctuation is not reduced at the stage where the final device is obtained.
- the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a silicon carbide semiconductor device capable of reducing fluctuations in threshold voltage and a method for manufacturing the same.
- a silicon carbide semiconductor device includes a silicon carbide substrate, a gate insulating film, and a gate electrode.
- the silicon carbide substrate has a first main surface and a second main surface opposite to the first main surface.
- the gate insulating film is provided in contact with the first main surface of the silicon carbide substrate.
- the gate electrode is provided on the gate insulating film so as to sandwich the gate insulating film between the silicon carbide substrate.
- the method for manufacturing a silicon carbide semiconductor device includes the following steps.
- An intermediate substrate including one main surface and the other main surface opposite to the one main surface is prepared.
- a sodium block member is disposed in contact with one main surface of the intermediate substrate.
- the intermediate substrate is annealed with the sodium block member in contact with one main surface. After the step of annealing the intermediate substrate, the sodium block member is removed from one main surface.
- the intermediate substrate has a first main surface facing one main surface, and a silicon carbide having a second main surface opposite to the first main surface and constituting the other main surface of the intermediate substrate
- the substrate includes a gate insulating film partially in contact with the first main surface of the silicon carbide substrate, and a source electrode in contact with the first main surface exposed from the gate insulating film.
- the diffusion length of sodium with respect to the sodium block member is not more than the diffusion length of sodium with respect to silicon carbide.
- the method for manufacturing a silicon carbide semiconductor device includes the following steps.
- An intermediate substrate including one main surface and the other main surface opposite to the one main surface is prepared.
- a first sodium absorbing member is disposed in contact with one main surface of the intermediate substrate.
- the intermediate substrate is annealed with the first sodium absorbing member in contact with one main surface.
- the first sodium absorbing member is removed from one main surface.
- the intermediate substrate has a first main surface opposed to one main surface and a second main surface opposite to the first main surface and constituting the other main surface of the intermediate substrate.
- a silicon substrate, a gate insulating film in partial contact with the first main surface of the silicon carbide substrate, and a source electrode in contact with the first main surface exposed from the gate insulating film are included.
- the diffusion length of sodium with respect to the first sodium absorbing member is larger than the diffusion length of sodium with respect to silicon carbide.
- FIG. 3 is a schematic cross sectional view for schematically illustrating a first step of the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 6 is a schematic cross sectional view for schematically illustrating a second step of the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross sectional view for schematically illustrating a third step in the method for manufacturing a silicon carbide semiconductor device according to one embodiment of the present invention. It is a cross-sectional schematic diagram for demonstrating schematically the 4th process of the manufacturing method of the silicon carbide semiconductor device which concerns on one embodiment of this invention.
- FIG. 10 is a schematic cross sectional view for schematically illustrating a fifth step of the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross sectional view for schematically illustrating a third step in the method for manufacturing a silicon carbide semiconductor device according to one embodiment of the present invention. It is a cross-sectional schematic diagram for demonstrating schematically the 4th process of the manufacturing method of the silicon carbide semiconductor device which concerns on one embodiment of this invention.
- FIG. 10 is a
- FIG. 10 is an enlarged schematic cross-sectional view for schematically illustrating a fifth step of the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 10 is a schematic cross sectional view for schematically illustrating a sixth step of the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention. It is a cross-sectional schematic diagram for demonstrating schematically the structure of TEG (Test Element Group) for measuring a sodium concentration. It is a figure which shows the relationship between a sodium concentration and the depth from the polysilicon surface.
- FIG. 10 is a schematic cross sectional view for schematically illustrating a first example of a first modification of the fifth step of the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross sectional view for schematically illustrating a second example of the first modification of the fifth step in the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross sectional view for schematically illustrating a third example of the first modification of the fifth step of the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 12 is a schematic cross sectional view for schematically illustrating a first example of a second modification of the fifth step of the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 12 is a schematic cross sectional view for schematically illustrating a second example of the second modification of the fifth step in the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross-sectional view for schematically illustrating a third example of the second modification of the fifth step in the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross sectional view for schematically illustrating a fourth example of the second modification of the fifth step in the method for manufacturing a silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross-sectional view for schematically illustrating a fifth example of the second modification of the fifth step in the method for manufacturing a silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross-sectional view for schematically illustrating a third example of the second modification of the fifth step in the method for manufacturing the silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross sectional view for schematically illustrating a fourth example of the second modification of the fifth step in the method for manufacturing a silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 11 is a schematic cross sectional view for schematically illustrating a sixth example of the second modification of the fifth step in the method for manufacturing a silicon carbide semiconductor device according to one embodiment of the present invention.
- FIG. 12 is a schematic cross sectional view for schematically illustrating a seventh example of the second modification of the fifth step in the method for manufacturing a silicon carbide semiconductor device according to one embodiment of the present invention. It is a cross-sectional schematic diagram for demonstrating schematically the 8th example of the 2nd modification of the 5th process of the manufacturing method of the silicon carbide semiconductor device which concerns on one embodiment of this invention. It is a figure explaining the variation
- metal impurities adhere to the surface of the interlayer insulating film provided on the silicon carbide substrate.
- Metal impurities such as sodium enter the gate electrode from the surface of the interlayer insulating film and diffuse to the vicinity of the gate insulating film by the heat treatment in the source electrode forming step and the step after the source electrode forming step. It is considered that these metal impurities supply electric charges during the operation of the MOSFET, whereby the threshold voltage is lowered and a current easily flows.
- the threshold voltage fluctuation due to gate bias stress can be effectively reduced by setting the total number of sodium in the vicinity of the gate insulating film to a certain value or less.
- the interface between the gate insulating film and the gate electrode is the first interface
- the interface between the gate insulating film and the silicon carbide substrate is the region facing the first interface as the second interface.
- a first virtual plane separated from the first interface by the thickness of the gate insulating film toward the gate electrode along the normal direction of the first interface, and a second interface along the normal direction of the second interface A value obtained by dividing the total number of sodium contained in the interface region sandwiched between the second virtual plane separated from the silicon carbide substrate by the thickness of the gate insulating film from the first interface area is 5 ⁇ 10 10 atoms / Controlled to cm 2 or less.
- ICP-MS Inductively Coupled Plasma Mass Spectrometry
- Sample 1 and sample 2 are silicon substrates
- sample 3 and sample 4 are silicon carbide substrates.
- the sodium concentration on the surface of the silicon substrate after the heat treatment was 170 ⁇ 10 9 atoms / cm 2 and 140 ⁇ 10 9 atoms / cm 2 .
- the sodium concentration on the surface of the silicon carbide substrate after the heat treatment was 1700 ⁇ 10 9 atoms / cm 2 and 1500 ⁇ 10 9 atoms / cm 2 . That is, the sodium concentration on the surface of the silicon carbide substrate was an order of magnitude higher than the sodium concentration on the surface of the silicon substrate. The same relationship has been confirmed even when the temperature and time of the heat treatment are changed.
- the silicon carbide substrate accumulates more sodium on the surface of the substrate because the diffusion of sodium into the substrate is slower than the silicon substrate. Therefore, in the case of using a silicon carbide substrate, strict management and reduction of the concentration inside the substrate are required for reducing the contamination of impurities, compared to the case of using a silicon substrate.
- the silicon carbide semiconductor device includes a silicon carbide substrate 10, a gate insulating film 15, and a gate electrode 27.
- Silicon carbide substrate 10 has a first main surface 10a and a second main surface 10b opposite to the first main surface 10a.
- Gate insulating film 15 is provided in contact with first main surface 10a of silicon carbide substrate 10.
- Gate electrode 27 is provided on gate insulating film 15 so as to sandwich gate insulating film 15 between silicon carbide substrate 10.
- the silicon carbide semiconductor device when performing a second stress test in which a gate voltage of ⁇ 10 V is applied to the gate electrode 27 for 100 hours at a temperature of 150 ° C.
- the threshold voltage before the second stress test is the third threshold voltage
- the threshold voltage after the second stress test is the fourth threshold voltage
- the third threshold voltage and the fourth threshold voltage The absolute value of the difference from the threshold voltage is 0.1 V or less. Thereby, the fluctuation
- the interface between gate insulating film 15 and gate electrode 27 is first interface 15a, and gate insulating film 15 and silicon carbide substrate 10 are
- the gate is formed by the thickness of the gate insulating film 15 from the first interface 15a along the normal direction of the first interface 15a.
- a value obtained by dividing the total number of sodium contained in the interface region R sandwiched between 2b by the area of the first interface 15a is 5 ⁇ 10 10 atoms / cm 2 or less.
- the maximum value of the sodium concentration in the region within 10 nm from the third main surface 27a opposite to the second interface 15b of the gate electrode 27 is It is larger than the maximum value of the sodium concentration in the interface region R, and the maximum value of the sodium concentration in the interface region R is 1 ⁇ 10 16 atoms / cm 3 or less.
- the third main surface 27a opposite to the second interface 15b of the gate electrode 27 is covered, and gate insulation is performed.
- Interlayer insulating film 21 provided in contact with film 15 and source electrode 16 in contact with first main surface 10a of silicon carbide substrate 10 are further provided.
- the diffusion length of sodium is L T (nm), and the first interface from the surface 21c of the interlayer insulating film 21 opposite to the third main surface 27a in the direction along the normal direction Y of the first interface 15a.
- the maximum value of the sodium concentration in the region within 10 nm from second main surface 10b of silicon carbide substrate 10 is the interface region It is larger than the maximum value of sodium concentration in R.
- the method for manufacturing the silicon carbide semiconductor device includes the following steps.
- An intermediate substrate 100 including one main surface 21c and the other main surface 10b opposite to the one main surface 21c is prepared.
- the sodium block member 7a is disposed in contact with one main surface 21c of the intermediate substrate 100.
- the intermediate substrate 100 is annealed with the sodium block member 7a in contact with the one main surface 21c.
- the sodium block member 7a is removed from one main surface 21c.
- the intermediate substrate 100 has a first main surface 10a facing one main surface 21c and a second main surface 10b opposite to the first main surface 10a and constituting the other main surface 10b of the intermediate substrate 100.
- Silicon carbide substrate 10 having main surface 10b, gate insulating film 15 partially in contact with first main surface 10a of silicon carbide substrate 10, and first main surface 10a exposed from gate insulating film 15 are in contact with each other.
- Source electrode 16 The diffusion length of sodium with respect to the sodium block member 7a is not more than the diffusion length of sodium with respect to silicon carbide.
- the sodium blocking member 7a can effectively block sodium from entering the one main surface 21c of the intermediate substrate 100 from the outside. Therefore, since the sodium concentration in interface region R can be kept low, fluctuations in the threshold voltage of the silicon carbide semiconductor device can be reduced.
- the sodium block member 7a includes a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and It includes at least one selected from the group consisting of layers in which a silicon carbide layer is coated on the carbon layer.
- the sodium block member 7a includes a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and It includes at least one selected from the group consisting of layers in which a silicon carbide layer is coated on the carbon layer.
- the method further includes a step of disposing intermediate substrate holding portion 4 facing the other main surface 10b of intermediate substrate 100.
- the diffusion length of sodium with respect to the intermediate substrate holding part 4 is not more than the diffusion length of sodium with respect to silicon carbide.
- the intermediate substrate holding part 4 can effectively block sodium from being mixed into the main surface 10 b on the other side of the intermediate substrate 100.
- intermediate substrate holding portion 4 is a carbon layer, a silicon carbide layer, a tantalum carbide layer, or a layer in which a silicon carbide layer is coated on a silicon layer. And at least one selected from the group consisting of layers in which a silicon carbide layer is coated on the carbon layer. Thereby, it can block more effectively that sodium is mixed into the main surface 10b on the other side of the intermediate substrate 100.
- the method further includes a step of arranging a lid portion 6 that contacts the intermediate substrate holding portion 4 and covers the sodium block member 7a.
- the intermediate substrate 100 is annealed in a state where the intermediate substrate 100 is disposed in the space surrounded by the lid portion 6 and the intermediate substrate holding portion 4.
- the diffusion length of sodium with respect to the lid 6 is not more than the diffusion length of sodium with respect to silicon carbide.
- the lid 6 can effectively block sodium from entering the main surface 21 c on one side of the intermediate substrate 100.
- lid 6 is formed of a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and carbon. It includes at least one selected from the group consisting of layers coated with a silicon carbide layer on the layer. Thereby, it can block more effectively that sodium is mixed into one of the intermediate substrates 100 in the main surface 21c.
- a method for manufacturing a silicon carbide semiconductor device includes the following steps.
- An intermediate substrate 100 including one main surface 21c and the other main surface 10b opposite to the one main surface 21c is prepared.
- the first sodium absorbing member 7b is disposed in contact with one main surface 21c of the intermediate substrate 100.
- the intermediate substrate 100 is annealed with the first sodium absorbing member 7b in contact with the one main surface 21c.
- the first sodium absorbing member 7b is removed from the one main surface 21c.
- the intermediate substrate 100 has a first main surface 10a facing one main surface 21c and a second main surface 10b opposite to the first main surface 10a and constituting the other main surface 10b of the intermediate substrate 100.
- the diffusion length of sodium with respect to the first sodium absorbing member 7b is larger than the diffusion length of sodium with respect to silicon carbide. Therefore, even when one main surface 21c of the intermediate substrate 100 is contaminated with sodium, the sodium on the one main surface 21c of the intermediate substrate 100 is absorbed by the first sodium absorbing member 7b, The sodium concentration on one main surface 21c of the intermediate substrate 100 can be effectively reduced. Therefore, since the sodium concentration in interface region R can be kept low, fluctuations in the threshold voltage of the silicon carbide semiconductor device can be reduced.
- the first sodium absorbing member 7b includes a silicon layer, a silicon dioxide layer, a silicon layer coated with a silicon dioxide layer, and a silicon dioxide layer. It includes at least one selected from the group consisting of layers in which a silicon layer is coated on the silicon layer. Thereby, sodium on one main surface 21c of intermediate substrate 100 can be absorbed more effectively.
- the thickness of the first sodium sucking member 7b is 300 ⁇ m or more in a sectional view.
- sodium on one main surface 21c of intermediate substrate 100 can be absorbed more effectively.
- the second main surface 10b of intermediate substrate 100 is in contact with the other main surface 10b before the step of annealing intermediate substrate 100.
- the step of disposing the second sodium absorbing member 7c and the step of removing the second sodium absorbing member 7c from the other main surface 10b after the step of annealing the intermediate substrate 100 are further provided.
- the first sodium absorbing member 7b is in contact with one main surface 21c of the intermediate substrate 100
- the second sodium absorbing member 7c is in contact with the other main surface 10b of the intermediate substrate 100.
- the intermediate substrate 100 is annealed.
- the diffusion length of sodium with respect to the second sodium absorbing member 7c is larger than the diffusion length of sodium with respect to silicon carbide.
- the sodium on the other major surface 10b of the intermediate substrate 100 can be effectively sucked from the second sodium sucking member 7c.
- the step of disposing intermediate substrate holding portion 4 facing the other main surface 10b of intermediate substrate 100 is further included.
- the diffusion length of sodium with respect to the intermediate substrate holding part 4 is not more than the diffusion length of sodium with respect to silicon carbide.
- the intermediate substrate holding part 4 can effectively block sodium from being mixed into the main surface 10 b on the other side of the intermediate substrate 100.
- intermediate substrate holding portion 4 is a carbon layer, a silicon carbide layer, a tantalum carbide layer, or a layer in which a silicon carbide layer is coated on a silicon layer. And at least one selected from the group consisting of layers in which a silicon carbide layer is coated on the carbon layer. Thereby, it can block more effectively that sodium is mixed into the main surface 10b on the other side of the intermediate substrate 100.
- the step of disposing lid 6 in contact with intermediate substrate holding portion 4 and covering first sodium sucking member 7b Further prepare.
- the intermediate substrate 100 is annealed in a state where the intermediate substrate 100 is disposed in the space surrounded by the lid portion 6 and the intermediate substrate holding portion 4.
- the diffusion length of sodium with respect to the lid 6 is not more than the diffusion length of sodium with respect to silicon carbide.
- the lid 6 can effectively block sodium from entering the main surface 21 c on one side of the intermediate substrate 100.
- lid 6 is formed of a carbon layer, a silicon carbide layer, a tantalum carbide layer, a silicon layer coated with a silicon carbide layer, and carbon. It includes at least one selected from the group consisting of layers coated with a silicon carbide layer on the layer. Thereby, it can block more effectively that sodium is mixed into one of the intermediate substrates 100 in the main surface 21c.
- first sodium absorbing member 7b includes fourth main surface 7b2 in contact with one main surface 21c, A step of disposing the sodium block member 7a in contact with the fifth main surface 7b1 of the first sodium sucking member 7b, including the fourth main surface 7b2 and the fifth main surface 7b1 opposite to the fourth main surface 7b2. And a step of removing the sodium block member 7a from the intermediate substrate 100 after the step of annealing 100.
- the sodium block member 7a is in contact with the fifth main surface 7b1 of the first sodium absorbing member 7b, and the fourth main surface 7b2 of the first sodium absorbing member 7b is the intermediate substrate 100.
- the intermediate substrate 100 is annealed in contact with the one main surface 21c.
- the diffusion length of sodium with respect to the sodium block member 7a is not more than the diffusion length of sodium with respect to silicon carbide.
- the sodium blocking member 7a can more effectively block sodium from being mixed into the main surface 21c on one side of the intermediate substrate 100.
- the sodium block member 7a includes a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on the silicon layer, and It includes at least one selected from the group consisting of layers in which a silicon carbide layer is coated on the carbon layer. Thereby, it can block more effectively that sodium is mixed into one of the intermediate substrates 100 in the main surface 21c.
- MOSFET 1 As a silicon carbide semiconductor device according to an embodiment of the present invention will be described.
- MOSFET 1 includes a silicon carbide substrate 10, a gate electrode 27, a gate insulating film 15, an interlayer insulating film 21, a source electrode 16, a surface protective electrode 19, The drain electrode 20 and the back surface protective electrode 23 are mainly included.
- Silicon carbide substrate 10 has a first main surface 10a and a second main surface 10b opposite to first main surface 10a, and includes silicon carbide single crystal substrate 11 and silicon carbide single crystal substrate 11. And the silicon carbide epitaxial layer 5 provided in the main part.
- Silicon carbide single crystal substrate 11 is made of, for example, a polytype 4H hexagonal silicon carbide single crystal. Maximum diameter of first main surface 10a of silicon carbide substrate 10 is greater than 100 mm, preferably 150 mm or more, and more preferably 200 mm or more.
- First main surface 10a of silicon carbide substrate 10 is, for example, a surface that is off by 8 ° or less from a ⁇ 0001 ⁇ plane or a ⁇ 0001 ⁇ plane.
- the first main surface 10a is, for example, a surface that is off by about 8 ° or less from the (0001) surface or the (0001) surface
- the second main surface 10b is a (000-1) surface or ( 000-1) is a surface that is off by about 8 ° or less from the surface.
- Silicon carbide substrate 10 has a thickness of, for example, 700 ⁇ m or less, and preferably 600 ⁇ m or less.
- the thickness of silicon carbide substrate 10 is preferably 250 ⁇ m or more and less than 600 ⁇ m, more preferably 300 ⁇ m or more and less than 600 ⁇ m, further preferably 250 ⁇ m or more and 500 ⁇ m or less, and further preferably 350 ⁇ m or more and 500 ⁇ m or less.
- Silicon carbide epitaxial layer 5 has a drift region 12, a body region 13, a source region 14, and a contact region 18.
- the drift region 12 is an n-type (first conductivity type) region containing an impurity such as nitrogen.
- the impurity concentration in drift region 12 is, for example, about 5.0 ⁇ 10 15 cm ⁇ 3 .
- the body region 13 is a region having p-type (second conductivity type).
- Impurities contained in body region 13 are, for example, Al (aluminum) or B (boron).
- the impurity concentration contained in body region 13 is, for example, about 1 ⁇ 10 17 cm ⁇ 3 .
- the source region 14 is an n-type region containing an impurity such as phosphorus.
- the source region 14 is formed inside the body region 13 so as to be surrounded by the body region 13.
- the impurity concentration of the source region 14 is higher than the impurity concentration of the drift region 12.
- the impurity concentration of the source region 14 is, for example, 1 ⁇ 10 20 cm ⁇ 3 .
- Source region 14 is separated from drift region 12 by body region 13.
- Contact region 18 is a p-type region.
- the contact region 18 is provided so as to be surrounded by the source region 14 and is in contact with the body region 13.
- Contact region 18 contains an impurity such as Al or B at a higher concentration than the impurity contained in body region 13.
- the impurity concentration of Al or B in the contact region 18 is, for example, 1 ⁇ 10 20 cm ⁇ 3 .
- the gate insulating film 15 is formed in contact with the first main surface 10 a of the silicon carbide substrate 10 so as to extend from the upper surface of one source region 14 to the upper surface of the other source region 14. Gate insulating film 15 is in contact with source region 14, body region 13, and drift region 12 at first main surface 10 a of silicon carbide substrate 10. Gate insulating film 15 is made of, for example, silicon dioxide. The thickness a of the gate insulating film 15 is preferably about 10 nm to 100 nm, more preferably about 40 nm to 60 nm, for example, 45 nm.
- the gate electrode 27 is disposed in contact with the gate insulating film 15 so as to extend from one source region 14 to the other source region 14. Gate electrode 27 is provided on gate insulating film 15 so as to sandwich gate insulating film 15 between silicon carbide substrate 10. The gate electrode 27 is formed above the source region 14, the body region 13 and the drift region 12 via the gate insulating film 15.
- the gate electrode 27 is made of a conductor such as polysilicon doped with impurities or Al.
- Source electrode 16 extends from each of the pair of source regions 14 to contact region 18 in a direction away from gate insulating film 15 and is in contact with first main surface 10a of silicon carbide substrate 10. Has been. Source electrode 16 is in contact with first main surface 10a of silicon carbide substrate 10. Source electrode 16 is in contact with source region 14 and contact region 18 on first main surface 10a of silicon carbide substrate 10. Source electrode 16 includes, for example, TiAlSi and is in ohmic contact with silicon carbide substrate 10.
- the interlayer insulating film 21 is provided in contact with the gate electrode 27 and the gate insulating film 15.
- the interlayer insulating film 21 electrically insulates the gate electrode 27 and the source electrode 16 from each other.
- the interlayer insulating film 21 includes a first insulating film 21a provided so as to cover the gate electrode 27, and a second insulating film 21b provided so as to cover the first insulating film 21a.
- the second insulating film 21b may contain more phosphorus as an impurity than the first insulating film 21a.
- the surface protection electrode 19 is formed in contact with the source electrode 16 and includes a conductor such as Al. The surface protective electrode 19 is electrically connected to the source region 14 via the source electrode 16.
- Drain electrode 20 is provided in contact with second main surface 10b of silicon carbide substrate 10.
- the drain electrode 20 may be made of another material capable of making ohmic contact with the silicon carbide single crystal substrate 11 such as NiSi (nickel silicide). Thereby, drain electrode 20 is electrically connected to silicon carbide single crystal substrate 11.
- Back surface protective electrode 23 is formed in contact with the main surface of drain electrode 20 opposite to silicon carbide single crystal substrate 11.
- the back surface protective electrode 23 has a laminated structure including, for example, a Ti layer, a Pt layer, and an Au layer.
- the interface between the gate insulating film 15 and the gate electrode 27 is defined as a first interface 15a
- the interface between the gate insulating film 15 and the silicon carbide substrate 10 that faces the first interface 15a is defined as a second interface 15b.
- a region sandwiched between the second imaginary surface 2b that is separated from the second interface 15b by the thickness a of the gate insulating film 15 toward the silicon carbide substrate 10 along the Y is defined as an interface region R.
- the value obtained by dividing the total number of sodium contained in the interface region R by the area of the first interface 15a is preferably 5 ⁇ 10 10 atoms / cm 2 or less, more preferably 3 ⁇ 10 10 atoms / cm 2 or less. More preferably, it is 1 ⁇ 10 10 atoms / cm 2 or less.
- the value obtained by dividing the total number of sodium contained in interface region R by the area of first interface 15a is the value in interface region R per unit area (1 cm 2 ) of first interface 15a.
- the value obtained by dividing the total number of sodium contained in the interface region R by the area of the first interface 15a is the total number of sodium atoms contained in the rectangular parallelepiped shown in FIG.
- the total number of sodium can be measured by SIMS (Secondary Ion-microprobe Mass Spectrometer).
- the maximum value of the sodium concentration in the region within 10 nm from the third main surface 27a opposite to the second interface 15b of the gate electrode 27 is larger than the maximum value of the sodium concentration in the interface region R.
- the maximum value of the sodium concentration in the region R is 1 ⁇ 10 16 atoms / cm 3 or less.
- the maximum value of the sodium concentration in the region within 10 nm from the third major surface 27a of the gate electrode 27 may be 1 ⁇ 10 18 atoms / cm 3 or more.
- the maximum value of sodium concentration in the region within 10 nm from second main surface 10b of silicon carbide substrate 10 is larger than the maximum value of sodium concentration in interface region R. Note that the region within 10 nm from the main surface is a region sandwiched by surfaces ⁇ 10 nm away from the main surface along the normal direction Y of the first interface 15a.
- the drain current (that is, the source-drain current I d ) is measured by changing the gate voltage (that is, the gate-source voltage V gs ).
- the gate voltage that is, the gate-source voltage V gs .
- the threshold voltage is a gate voltage at which a drain current starts to flow. More specifically, the threshold voltage is a gate voltage at which the drain current becomes 300 ⁇ A when the source-drain voltage (V ds ) is 10V.
- variation of the threshold voltage of a silicon carbide semiconductor device is demonstrated.
- the drain current is measured by changing the gate voltage applied to the silicon carbide semiconductor device, and the relationship 3a between the gate voltage and the drain current is plotted.
- the voltage between the source and the drain is 10 V
- the gate voltage at which the drain current becomes 300 ⁇ A is defined as the first threshold voltage (V th1 ).
- a stress test is performed in which a negative voltage is applied to gate electrode 27 of the silicon carbide semiconductor device for a certain period of time.
- the drain voltage is measured by changing the gate voltage applied to the silicon carbide semiconductor device, and the relationship 3b between the gate voltage and the drain current is plotted.
- the threshold voltage When the voltage between the source and the drain is 10 V, the gate voltage at which the drain current becomes 300 ⁇ A is defined as the second threshold voltage (V th2 ). As shown in FIG. 4, the threshold voltage may fluctuate after the stress test. In particular, when the threshold voltage fluctuates to the negative side, a switch operation that should be normally off may be turned on.
- the MOSFET 1 when a first stress test is performed in which a gate voltage of ⁇ 5 V is applied to the gate electrode 27 at a temperature of 175 ° C. for 100 hours, before the first stress test is performed.
- the threshold voltage of the first threshold voltage is the first threshold voltage and the threshold voltage after the first stress test is the second threshold voltage
- the absolute value of the difference between the first threshold voltage and the second threshold voltage is 0.5 V or less, preferably 0.3 V or less, more preferably 0.1 V or less.
- the second threshold voltage may be higher than the first threshold voltage or lower than the first threshold voltage.
- the threshold voltage before the first stress test is set to the first threshold voltage.
- the threshold voltage after the first stress test is performed is the second threshold voltage
- the absolute value of the difference between the first threshold voltage and the second threshold voltage is 0.5 V or less.
- it is 0.3V or less, More preferably, it is 0.1V or less.
- the second threshold voltage may be higher than the first threshold voltage or lower than the first threshold voltage.
- the threshold voltage before the first stress test is performed.
- the absolute value of the difference between the first threshold voltage and the second threshold voltage is 0 0.5V or less, preferably 0.3V or less, more preferably 0.1V or less.
- the second threshold voltage may be higher than the first threshold voltage or lower than the first threshold voltage.
- the threshold voltage before the second stress test is set to the third threshold voltage.
- the threshold voltage after the second stress test is the fourth threshold voltage, the absolute value of the difference between the third threshold voltage and the fourth threshold voltage (in other words, the threshold voltage Fluctuation amount) is 0.1 V or less.
- the fourth threshold voltage may be higher than the third threshold voltage or lower than the third threshold voltage.
- the threshold voltage before the second stress test is set to the third threshold voltage.
- the threshold voltage after the second stress test is performed is the fourth threshold voltage
- the absolute value of the difference between the third threshold voltage and the fourth threshold voltage is 0.1 V or less. It is.
- the fourth threshold voltage may be higher than the third threshold voltage or lower than the third threshold voltage.
- MOSFET 1 as the silicon carbide semiconductor device according to the present embodiment will be described.
- silicon carbide substrate preparation step (S10: FIG. 5) is performed.
- silicon carbide single crystal substrate 11 is prepared by slicing an ingot made of a hexagonal silicon carbide single crystal having polytype 4H formed by a sublimation method.
- silicon carbide epitaxial layer 5 is formed on silicon carbide single crystal substrate 11 by, for example, a CVD (Chemical Vapor Deposition) method.
- a carrier gas containing hydrogen (H 2 ) and a source gas containing monosilane (SiH 4 ), propane (C 3 H 8 ), nitrogen (N 2 ), and the like on the silicon carbide single crystal substrate 11 Is supplied, and silicon carbide single crystal substrate 11 is heated to, for example, about 1500 ° C.
- silicon carbide epitaxial layer 5 is formed on silicon carbide single crystal substrate 11.
- silicon carbide substrate 10 having first main surface 10a and second main surface 10b opposite to first main surface 10a is prepared.
- Silicon carbide substrate 10 includes silicon carbide single crystal substrate 11 forming second main surface 10b, and silicon carbide epitaxial layer 5 provided on silicon carbide single crystal substrate 11 and forming first main surface 10a. Including.
- an ion implantation step (S20: FIG. 5) is performed. Specifically, referring to FIG. 7, ion implantation is performed on first main surface 10 a of silicon carbide substrate 10.
- ion implantation is performed on first main surface 10 a of silicon carbide substrate 10.
- Al (aluminum) ions are implanted into first main surface 10a of silicon carbide substrate 10, whereby p type body region 13 is formed in silicon carbide epitaxial layer 5.
- P (phosphorus) ions are implanted into the body region 13 at a depth shallower than the implantation depth of the Al ions, thereby forming the source region 14 having the n-type conductivity.
- Al ions are further implanted into the source region 14, thereby forming a contact region 18 surrounded by the source region 14, having a depth equivalent to that of the source region 14, and having a p-type conductivity. Is done.
- silicon carbide epitaxial layer 5 a region where none of body region 13, source region 14, and contact region 18 is formed becomes drift region 12.
- body region 13, source region 14, and contact region 18 are formed on the first main surface 10 a side of silicon carbide substrate 10.
- an activation annealing step (S30: FIG. 5) is performed. Specifically, silicon carbide substrate 10 is heated for about 30 minutes at a temperature of 1600 ° C. or higher and 2000 ° C. or lower, for example. As a result, impurities in the body region 13, the source region 14, and the contact region 18 formed in the ion implantation process are activated to generate desired carriers.
- a gate insulating film forming step (S40: FIG. 5) is performed.
- silicon carbide substrate 10 is heated at a temperature of about 1350 ° C. for about 1 hour in an atmosphere containing oxygen so as to cover first main surface 10 a of silicon carbide substrate 10.
- a gate insulating film 15 made of silicon dioxide is formed.
- the gate insulating film 15 has a drift region 12, a body region 13, a source region 14, and a first main surface 10 a so as to extend from one contact region 18 to the other contact region 18. , In contact with the contact region 18.
- silicon carbide substrate 10 on which gate insulating film 15 is formed in an atmosphere gas containing nitrogen such as nitrogen monoxide, dinitrogen monoxide, nitrogen dioxide and ammonia has a temperature of 1300 ° C. or higher and 1500 ° C. or lower. The temperature is maintained, for example, for about 1 hour.
- nitrogen atoms are trapped in traps that exist in the vicinity of the second interface 15 b between the gate insulating film 15 and the drift region 12. This suppresses the formation of interface states in the vicinity of the second interface 15b.
- silicon carbide substrate 10 on which gate insulating film 15 is formed is held in argon gas at a temperature of 1100 ° C. or higher and 1500 ° C. or lower for about 1 hour, for example.
- silicon carbide substrate 10 on which gate insulating film 15 is formed is maintained at a temperature of 1300 ° C. or higher and 1500 ° C. or lower.
- a gate electrode forming step (S50: FIG. 5) is performed.
- the gate electrode 27 made of polysilicon containing impurities is formed on the gate insulating film 15 by LPCVD (Low Pressure Chemical Vapor Deposition).
- Gate electrode 27 is formed to face drift region 12, source region 14, and body region 13 with gate insulating film 15 interposed therebetween.
- interlayer insulating film forming step (S60: FIG. 5) is performed.
- interlayer insulating film 21 made of silicon dioxide is formed to cover gate insulating film 15 and gate electrode 27.
- TEOS Tetraethylorthosilicate
- silicon carbide substrate 10 is heated for about 30 minutes at a temperature of about 800 ° C. to 900 ° C., for example.
- a PSG Phosphorus Silicon Glass
- the interlayer insulating film 21 including the first insulating film 21a provided so as to cover the gate electrode 27 and the second insulating film 21b provided so as to cover the first insulating film 21a is formed.
- the second insulating film 21b contains more phosphorus as an impurity than the first insulating film 21a.
- a source electrode forming step (S70: FIG. 5) is performed. Referring to FIG. 9, interlayer insulating film 21 and gate insulating film 15 are removed in a region where source electrode 16 is to be formed, and source region 14 and contact region 18 are exposed from interlayer insulating film 21 and gate insulating film 15. Is formed. Next, source electrode 16 including, for example, NiSi, TiSi, TiAl, or TiAlSi (titanium aluminum silicon) is formed in the above region by, for example, sputtering. Source electrode 16 is formed in contact with first main surface 10a of silicon carbide substrate 10.
- intermediate substrate 100 silicon carbide substrate 10 (hereinafter referred to as intermediate body 100 or intermediate substrate 100) provided with source electrode 16, gate electrode 27, interlayer insulating film 21, and gate insulating film 15 is formed.
- Intermediate substrate 100 includes one main surface 21c and the other main surface 10b opposite to one main surface 21c.
- the intermediate substrate 100 has a first main surface 10a facing one main surface 21c and a second main surface 10b opposite to the first main surface 10a and constituting the other main surface 10b of the intermediate substrate 100.
- Silicon carbide substrate 10 having main surface 10b, gate insulating film 15 partially in contact with first main surface 10a of silicon carbide substrate 10, and first main surface 10a exposed from gate insulating film 15 are in contact with each other.
- Source electrode 16 see FIG. 11).
- the alloying annealing step (S80: FIG. 5) includes a step of mounting the cover member on the intermediate substrate and a step of annealing the intermediate substrate on which the cover member is mounted.
- a process of mounting the cover member on the intermediate substrate is performed.
- the intermediate body 100 is arrange
- Cover member 2 is arranged to cover intermediate body 100.
- the lid portion 6 made of carbon may be disposed above the cover member 2, and the intermediate body 100 provided with the cover member 2 may be surrounded by the tray 4 and the lid portion 6.
- Second main surface 10b of silicon carbide substrate 10 included in intermediate body 100 is disposed in contact with the tray.
- Cover member 2 is made of, for example, silicon carbide or silicon, preferably silicon carbide.
- the cover member 2 has a thickness of about 300 ⁇ m to 1 mm, for example.
- cover member 2 is in contact with surface 21 c of interlayer insulating film 21, and cover member 2 is a first member of silicon carbide substrate 10 such that cover member 2 is separated from source electrode 16. It may be arranged on the main surface 10a side. Preferably, cover member 2 is provided so as to cover the entire first main surface 10a of silicon carbide substrate 10. Next, a step of annealing the intermediate substrate on which the cover member is mounted is performed. Specifically, the cover member 2 is in contact with the interlayer insulating film 21, and the cover member 2 is disposed on the first main surface 10 a side of the silicon carbide substrate 10 so that the cover member 2 is separated from the source electrode 16.
- silicon carbide substrate 10 provided with source electrode 16 and cover member 2 are heated, for example, at 900 ° C. or higher and 1100 ° C. or lower for about 5 minutes.
- the source electrode 16 is silicided, and the source electrode 16 that is in ohmic contact with the source region 14 is formed.
- metal impurities such as sodium present in the annealing furnace cause first impurities of silicon carbide substrate 10 to be present. It can suppress adhering to the surface 21c of the interlayer insulation film 21 arrange
- cover member 2 is disposed so as to cover the intermediate body 100, alloying annealing is performed on the intermediate body 100 and the cover member 2, thereby suppressing diffusion of metal impurities such as sodium into the interface region R. can do.
- cover member 2 is removed from the first main surface 10a side of silicon carbide substrate 10.
- sodium block member 7 a is arranged in contact with one main surface 21 c of intermediate substrate 100.
- the sodium block member 7a has a sixth main surface 7a2 in contact with the one main surface 21c of the intermediate substrate 100, and a seventh main surface 7a1 opposite to the sixth main surface 7a2.
- the sixth main surface 7a2 of the sodium block member 7a is disposed so as to cover the entire surface of the one main surface 21c of the intermediate substrate 100.
- the width of the sodium block member 7a is equal to or larger than the width of the intermediate substrate 100 in a cross-sectional view (a visual field viewed along a direction parallel to the other main surface 10b of the intermediate substrate 100).
- the diffusion length of sodium with respect to the sodium block member 7a is not more than the diffusion length of sodium with respect to silicon carbide.
- the material constituting the sodium block member 7a is, for example, silicon carbide or carbon.
- sodium block member 7a is selected from the group consisting of a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and a layer in which a silicon carbide layer is coated on a carbon layer. At least one of
- a step of annealing the intermediate substrate on which the cover member is mounted is performed.
- the intermediate substrate 100 is annealed in a state where the sodium block member 7 a is in contact with one main surface 21 c of the intermediate substrate 100.
- Intermediate substrate 100 is annealed at, for example, 900 ° C. or more and 1100 ° C. or less for about 5 minutes.
- the sodium block member 7a is removed from one main surface 21c of the intermediate substrate 100.
- the sodium blocking member 7a can effectively block sodium from entering the one main surface 21c of the intermediate substrate 100 from the outside.
- sodium contamination from the outside contamination from trays and contamination from facilities are considered.
- a heater portion that becomes high temperature is considered to be one of the sources of sodium.
- intermediate substrate holding portion 4 may be arranged at a position facing the other main surface 10b of intermediate substrate 100.
- the intermediate substrate holding unit 4 is a tray capable of holding the intermediate substrate 100, for example.
- the intermediate substrate holding part 4 is in contact with the other main surface 10b so as to cover the entire surface of the other main surface 10b of the intermediate substrate 100, for example.
- the wall portion of the intermediate substrate holding portion 4 extends in the normal direction of the other main surface 10b of the intermediate substrate 100 so as to face the side surfaces of the intermediate substrate 100 and the sodium block member 7a.
- the width of the intermediate substrate holding part 4 is not less than the width of the intermediate substrate 100 in a sectional view.
- the shape of the intermediate substrate holding part 4 may be a shape in which one opening of the cylinder is closed, a disk shape, or other shapes.
- the diffusion length of sodium with respect to the intermediate substrate holding part 4 is not more than the diffusion length of sodium with respect to silicon carbide.
- the material constituting the intermediate substrate holding part 4 is, for example, carbon.
- intermediate substrate holding portion 4 is made of a group consisting of a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and a layer in which a silicon carbide layer is coated on a carbon layer. Including at least one selected.
- the intermediate substrate holding part 4 is made of carbon (graphite)
- sodium forms a Na—C compound in the graphite, so that the diffusion length of sodium into graphite is considered to be short.
- one main surface 21c of the intermediate substrate 100 is covered with the sodium block member 7a, and the other main surface 10b and side surfaces of the intermediate substrate 100 are covered with the intermediate substrate holding part 4.
- the intermediate substrate 100 is annealed.
- the temperature and time for annealing the intermediate substrate 100 are the same as those described above.
- the sodium block member 7 a is removed from one main surface 21 c of the intermediate substrate 100, and the intermediate substrate 100 is removed from the intermediate substrate holding unit 4.
- the lid portion 6 may be disposed so as to contact the intermediate substrate holding portion 4 and cover the sodium block member 7a.
- the lid 6 is configured so as to form a closed space surrounded by the lid 6 and the intermediate substrate holding unit 4 by being combined with the intermediate substrate holding unit 4.
- the sodium block member 7a and the intermediate substrate 100 are disposed in the closed space.
- the seventh main surface 7a1 of the sodium block member 7a may be separated from the lid portion 6 or may be in contact with the lid portion.
- the shape of the lid portion 6 may be a disc shape, a shape in which one opening of the cylinder is closed, or a shape in which the central portion of the disc projects. Other shapes may also be used.
- the intermediate substrate 100 is annealed in a state where the sodium block member 7a and the intermediate substrate 100 are disposed in the closed space surrounded by the lid portion 6 and the intermediate substrate holding portion 4. .
- the temperature and time for annealing the intermediate substrate 100 are the same as those described above.
- the diffusion length of sodium with respect to the lid 6 is not more than the diffusion length of sodium with respect to silicon carbide.
- the material which comprises the cover part 6 is carbon, for example.
- lid portion 6 is selected from the group consisting of a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and a layer in which a silicon carbide layer is coated on a carbon layer. Including at least one.
- first sodium absorbing member 7b is disposed in contact with one main surface 21c of intermediate substrate 100.
- the diffusion length of sodium with respect to the first sodium absorbing member 7b is larger than the diffusion length of sodium with respect to silicon carbide.
- the material constituting the first sodium absorbing member 7b is, for example, silicon.
- the first sodium absorbing member 7b is selected from the group consisting of a silicon layer, a silicon dioxide layer, a layer in which a silicon dioxide layer is coated on a silicon layer, and a layer in which a silicon layer is coated on a silicon dioxide layer.
- Silicon may be single crystal, polycrystal, amorphous, or a combination thereof.
- the width of the first sodium absorbing member 7b is equal to or greater than the width of the intermediate substrate 100 in a cross-sectional view.
- a step of annealing the intermediate substrate on which the cover member is mounted is performed. Specifically, the intermediate substrate 100 is annealed in a state where the first sodium sucking member 7b is in contact with the one main surface 21c. The temperature and time for annealing the intermediate substrate 100 are the same as those described above. After annealing the intermediate substrate 100, the first sodium absorbing member 7b is removed from one main surface 21c of the intermediate substrate 100. By absorbing the sodium on the one main surface 21c of the intermediate substrate 100 by the first sodium absorbing member 7b, the sodium concentration on the one main surface 21c of the intermediate substrate 100 can be effectively reduced.
- the diffusion of sodium to the intermediate substrate 100 can be suppressed by promoting gettering capture of impurities such as sodium at the interface between the intermediate substrate 100 and the first sodium absorbing member 7b.
- impurities such as sodium at the interface between the intermediate substrate 100 and the first sodium absorbing member 7b.
- the diffusion distance of sodium to silicon is about 500 nm
- the diffusion distance of sodium to silicon dioxide is about 400 nm.
- the thickness b of the first sodium absorbing member 7b is preferably 300 ⁇ m or more in a sectional view.
- the thickness b of first sodium absorbing member 7b is such that one main surface of intermediate substrate 100 extends from first main surface 10a of silicon carbide substrate 10 along the normal direction of first main surface 10a of silicon carbide substrate 10. It may be larger than the distance to the surface 21c.
- the second sodium absorbing member 7 c may be disposed in contact with the other main surface 10 b of the intermediate substrate 100. That is, the first sodium absorbing member 7b is disposed in contact with one main surface 21c of the intermediate substrate 100, and the second sodium absorbing member 7c is disposed in contact with the other main surface 10b of the intermediate substrate 100.
- the diffusion length of sodium with respect to the second sodium absorbing member 7c is larger than the diffusion length of sodium with respect to silicon carbide.
- the material constituting the second sodium absorbing member 7c is, for example, silicon.
- the material constituting the second sodium sucking member 7c is the same as the material constituting the first sodium sucking member 7b.
- the width of the second sodium sucking member 7c is equal to or larger than the width of the intermediate substrate 100.
- a step of annealing the intermediate substrate on which the cover member is mounted is performed. Specifically, in the state where the first sodium absorbing member 7b is in contact with one main surface 21c of the intermediate substrate 100 and the second sodium absorbing member 7c is in contact with the other main surface 10b of the intermediate substrate 100, the intermediate The substrate 100 is annealed. The temperature and time for annealing the intermediate substrate 100 are the same as those described above. After annealing the intermediate substrate 100, the first sodium absorbing member 7b is removed from one main surface 21c of the intermediate substrate 100, and the second sodium absorbing member 7c is removed from the other main surface 10b.
- intermediate substrate holding portion 4 may be arranged at a position facing the other main surface 10b of intermediate substrate 100.
- the intermediate substrate holding unit 4 is a tray capable of holding the intermediate substrate 100, for example.
- the intermediate substrate holding part 4 is in contact with the other main surface 10b so as to cover the entire surface of the other main surface 10b of the intermediate substrate 100, for example.
- the wall portion of the intermediate substrate holding portion 4 extends in the normal direction of the other main surface 10b of the intermediate substrate 100 so as to face the side surfaces of the intermediate substrate 100 and the sodium block member 7a.
- the width of the intermediate substrate holding part 4 is not less than the width of the intermediate substrate 100 in a sectional view.
- the shape of the intermediate substrate holding part 4 may be a shape in which one opening of the cylinder is closed, a disk shape, or other shapes.
- the diffusion length of sodium with respect to the intermediate substrate holding part 4 is not more than the diffusion length of sodium with respect to silicon carbide.
- the material constituting the intermediate substrate holding part 4 is, for example, carbon.
- intermediate substrate holding portion 4 is made of a group consisting of a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and a layer in which a silicon carbide layer is coated on a carbon layer. Including at least one selected.
- one main surface 21c of the intermediate substrate 100 is covered with the first sodium absorbing member 7b, and the other main surface 10b and side surfaces of the intermediate substrate 100 are intermediate substrate holding portions.
- the intermediate substrate 100 is annealed while being covered with the substrate 4.
- the temperature and time for annealing the intermediate substrate 100 are the same as those described above.
- the first sodium absorbing member 7b is removed from one main surface 21c of the intermediate substrate 100, and the intermediate substrate 100 is removed from the intermediate substrate holding part 4.
- first sodium absorbing member 7b is disposed in contact with one main surface 21c, and second sodium is in contact with the other main surface 10b.
- the intermediate substrate 100 on which the sucking member 7 c is disposed may be disposed so as to completely fill the recess formed in the intermediate substrate holding unit 4.
- the surface of the second sodium absorbing member 7c opposite to the surface in contact with the other main surface 10b of the intermediate substrate 100 is in contact with the intermediate substrate holding part 4, and the intermediate substrate 100, the first sodium absorbing member 7b, and the second
- the intermediate substrate 100 is disposed in a recess formed in the intermediate substrate holding part 4 so that each side surface of the sodium sucking member 7 c is covered with the intermediate substrate holding part 4.
- one main surface 21c of the intermediate substrate 100 is covered with the first sodium absorbing member 7b, and the other main surface 10b of the intermediate substrate 100 is opposed to the intermediate substrate holding portion 4.
- the intermediate substrate 100 is annealed in a state where the surface of the second sodium absorbing member 7c opposite to the surface in contact with the other main surface 10b of the intermediate substrate 100 is covered with the intermediate substrate holding part 4.
- the temperature and time for annealing the intermediate substrate 100 are the same as those described above.
- the first sodium absorbing member 7b is removed from one main surface 21c of the intermediate substrate 100, and the second sodium absorbing member 7c is removed from the other main surface 10b of the intermediate substrate 100,
- the intermediate substrate 100 is removed from the intermediate substrate holding unit 4.
- lid portion 6 may be disposed so as to be in contact with intermediate substrate holding portion 4 and to cover first sodium sucking member 7 b.
- the lid 6 is configured so as to form a closed space surrounded by the lid 6 and the intermediate substrate holding unit 4 by being combined with the intermediate substrate holding unit 4.
- the intermediate substrate 100 in which the first sodium absorbing member 7b is disposed on the one main surface 21c is disposed in the closed space.
- the first sodium absorbing member 7b includes a fourth main surface 7b2 in contact with one main surface 21c of the intermediate substrate 100, and a fifth main surface 7b1 opposite to the fourth main surface 7b2.
- the fifth main surface 7b1 of the first sodium absorbing member 7b may be separated from the lid 6 or may be in contact with the lid 6.
- the shape of the lid 6 is the same as the shape of the lid 6 described above.
- the first sodium absorption is made in contact with one main surface 21 c in the closed space surrounded by the lid portion 6 and the intermediate substrate holding portion 4.
- An intermediate substrate 100 in which the member 7b is disposed and the second sodium absorbing member 7c is disposed in contact with the other main surface 10b is disposed.
- the fifth main surface 7b1 of the first sodium absorbing member 7b is in contact with the lid portion 6.
- the intermediate substrate 100 is annealed in a state where the intermediate substrate 100 is disposed in the closed space surrounded by the lid portion 6 and the intermediate substrate holding portion 4.
- the temperature and time for annealing the intermediate substrate 100 are the same as those described above.
- the diffusion length of sodium with respect to the lid 6 is not more than the diffusion length of sodium with respect to silicon carbide.
- the material which comprises the cover part 6 is carbon, for example.
- lid portion 6 is selected from the group consisting of a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and a layer in which a silicon carbide layer is coated on a carbon layer. Including at least one.
- the sodium block member 7a may be disposed in contact with the fifth main surface 7b1 of the first sodium suction member 7b.
- the first sodium absorbing member 7b is disposed in contact with one main surface 21c of the intermediate substrate 100
- the sodium block member 7a is disposed in contact with the fifth main surface 7b1 of the first sodium absorbing member 7b.
- An intermediate substrate 100 is prepared.
- the diffusion length of sodium with respect to the sodium block member 7a is not more than the diffusion length of sodium with respect to silicon carbide.
- the material constituting the sodium block member 7a is, for example, silicon carbide or carbon.
- sodium block member 7a is selected from the group consisting of a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and a layer in which a silicon carbide layer is coated on a carbon layer.
- the width of the sodium block member 7 a is equal to or greater than the width of the intermediate substrate 100.
- second sodium suction member 7c may be arranged on the other main surface 10b of intermediate substrate 100. The material constituting the second sodium sucking member 7c is as described above.
- the first sodium absorbing member 7b is disposed in contact with one main surface 21c of the intermediate substrate 100
- the sodium blocking member 7a is disposed in contact with the fifth main surface 7b1 of the first sodium absorbing member 7b
- the intermediate substrate 100 in which the second sodium absorbing member 7c is arranged on the main surface 10b may be held by the intermediate substrate holding part 4, and the lid part 6 is further arranged in contact with the intermediate substrate holding part 4. Also good.
- the sodium block member 7a is in contact with the fifth main surface 7b1 of the first sodium absorbing member 7b, and the fourth main surface 7b2 of the first sodium absorbing member 7b is The intermediate substrate 100 is annealed in contact with the one main surface 21c of the intermediate substrate 100. Furthermore, the intermediate substrate 100 may be annealed in a state where the second sodium absorbing member 7c is disposed in contact with the other main surface 10b of the intermediate substrate 100. After annealing the intermediate substrate 100, the sodium block member 7a and the first sodium absorbing member 7b are removed from the intermediate substrate 100. When the second sodium sucking member 7c is disposed in contact with the other main surface 10b of the intermediate substrate 100, the second sodium sucking member 7c is removed from the intermediate substrate 100.
- the surface protection electrode 19 is formed so as to contact the source electrode 16 and cover the interlayer insulating film 21.
- the surface protective electrode 19 is preferably made of a material containing Al, for example, AlSiCu.
- a lamp annealing process may be performed. In the lamp annealing step, silicon carbide substrate 10 provided with surface protective electrode 19 may be heated, for example, at a temperature of 700 ° C. or higher and 800 ° C. or lower for about 30 seconds, for example.
- a passivation film forming step may be performed. A passivation film (not shown) is provided on the surface protection electrode 19, for example.
- silicon carbide substrate 10 provided with surface protective electrode 19 is heated, for example, at a temperature of about 400 ° C. to 450 ° C. for about 70 seconds, for example.
- a sintering process may be performed. In the sintering process, the silicon carbide substrate 10 provided with the passivation film is heated at a temperature of about 350 ° C. to 450 ° C. for about 15 minutes, for example.
- drain electrode 20 made of, for example, NiSi is formed in contact with second main surface 10b of silicon carbide substrate 10.
- the drain electrode 20 may be TiAlSi, for example.
- the formation of the drain electrode 20 is preferably performed by a sputtering method, but may be performed by vapor deposition.
- the drain electrode 20 is heated by, for example, laser annealing.
- the back surface protective electrode 23 is formed in contact with the drain electrode 20.
- the back surface protective electrode 23 is preferably made of a material containing Al. As described above, MOSFET 1 shown in FIG. 1 is manufactured.
- the intermediate including source electrode 16, gate electrode 27, gate insulating film 15, interlayer insulating film 21, and silicon carbide substrate 10 in the steps after the alloying annealing step.
- the heat treatment temperature and time for 100 are controlled as follows.
- the diffusion length of sodium is L T (nm), and the interlayer insulating film 21 on the side opposite to the third main surface of the gate electrode 27 in the direction along the normal direction Y of the first interface 15a.
- N 0 (cm ⁇ 3 ) the sodium concentration on the surface 21c of the interlayer insulating film 21 is N 0 (cm ⁇ 3 )
- N 0 ⁇ L T / x The temperature and time of heat treatment performed on the gate electrode 27 and the interlayer insulating film 21 after the step of annealing the source electrode (including the step of annealing the source electrode) are controlled so that ⁇ 1.52 ⁇ 10 20. Is done.
- the N 0 ⁇ L T / x is less than 1.52 ⁇ 10 20 ⁇ 0.85, more preferably less than 1.52 ⁇ 10 20 ⁇ 0.70.
- an alloying annealing process that is, a process of annealing the source electrode
- a lamp annealing process a sintering process
- a passivation film forming process are performed on intermediate 100 including gate electrode 27 and interlayer insulating film 21.
- the intermediate body 100 is heat-treated at a temperature of 1000 ° C. for 15 minutes.
- the intermediate body 100 is heat-treated at a temperature of 740 ° C. for 30 seconds.
- the sintering process heat treatment is performed on the intermediate 100 at a temperature of 400 ° C. for 15 minutes.
- the intermediate body 100 is heat-treated at a temperature of 420 ° C. for 70 seconds.
- a heat treatment step in which a temperature of 300 ° C. or higher, which is a high temperature exceeding the heat resistance of the resist, is added to the intermediate 100 is added, the diffusion length in the heat treatment step is added to add the total sodium. diffusion length L T is calculated.
- L A is the diffusion length of sodium in the alloying annealing process
- L L is the diffusion length of sodium in the lamp annealing process
- L S is the diffusion length of sodium in the sintering process
- L P is the passivation. It is the diffusion length of sodium in the film forming process.
- the diffusion length L is calculated by the following formula 1.
- D is a diffusion coefficient
- t is a heat treatment time (second).
- the diffusion coefficient D is calculated by the following formula 2.
- D 0 is a diffusion constant (m 2 / sec)
- Q is an activation energy (kJ / mol)
- R is a gas constant of 8.31 (J / mol ⁇ K)
- T is a heat treatment.
- the diffusion constant D 0 of sodium in the gate electrode 27 made of polysilicon is 1 ⁇ 10 ⁇ 6 (cm 2 / sec), and the activation energy Q is 122 (kJ / mol).
- the diffusion coefficient D is calculated.
- the diffusion coefficient in the alloying annealing step (1000 ° C.) is 9.80 ⁇ 10 ⁇ 12 (m 2 / sec), and the diffusion coefficient in the lamp annealing step (740 ° C.) is 5.08 ⁇ 10 ⁇ 13 (m 2 / sec).
- the diffusion coefficient in the passivation formation step (420 ° C.) is 6.30 ⁇ 10 ⁇ 16 (m 2 / sec), and the diffusion coefficient in the sintering process (400 ° C.) is 3.36 ⁇ 10 ⁇ 16 (m 2). / Second).
- the diffusion length L A in the alloying annealing step (900 seconds) is 187871 nm
- the diffusion length L L in the lamp annealing step (30 seconds) is 7808 nm
- the diffusion length L P in the passivation formation step (70 seconds) is 1100 nm.
- the diffusion length L S in the processing step (900 seconds) is 420 nm.
- the distance x is the first interface 15a from the surface 21c of the interlayer insulating film 21 opposite to the third main surface 27a of the gate electrode 27 in the direction along the normal direction Y of the first interface 15a. It is the distance to.
- the distance x is the sum of the film thickness of the interlayer insulating film 21 and the film thickness of the gate insulating film 15.
- the distance x is 1300 nm.
- the sodium concentration N 0 is the sodium concentration on the surface 21c of the interlayer insulating film 21 before the alloying annealing is performed.
- the sodium concentration N 0 is, for example, 1 ⁇ 10 18 cm ⁇ 3 .
- the threshold voltage fluctuates significantly.
- the heat treatment temperature and the heat treatment time of the heat treatment step after the step of alloying annealing of the source electrode 16 are controlled so that N 1 / N 10 ⁇ 1 (Formula 4).
- the total diffusion length of sodium with respect to the gate electrode 27 is 117796 nm.
- the distance x is 1300 nm and the sodium concentration N 0 is 1 ⁇ 10 18 cm ⁇ 3
- the sodium concentration N l is 9.06 ⁇ 10 19 cm ⁇ 3 . That is, N 1 / N 10 is about 0.6.
- a MOSFET having a configuration in which the n-type and the p-type are interchanged may be used.
- a planar type MOSFET has been described as an example of the silicon carbide semiconductor device of the present invention.
- the silicon carbide semiconductor device may be, for example, a trench type MOSFET, an IGBT, or the like.
- the surface 21c of the intermediate substrate 100 in the description of FIGS. 15 to 25 of the above embodiment may be upward or downward in the gravity direction.
- the arrangement of each of the sodium blocking member 7a, the first sodium absorbing member 7b, and the second sodium absorbing member 7b is determined based on the position of the surface 21c of the intermediate substrate 100, and the surface 21c of the intermediate substrate 100 is determined. It does not change depending on the direction of the.
- MOSFET 1 when the first stress test is performed in which a gate voltage of ⁇ 5 V is applied to gate electrode 27 for 100 hours at a temperature of 175 ° C., the first stress test is performed.
- the threshold voltage before the first threshold voltage is set as the first threshold voltage and the threshold voltage after the first stress test is set as the second threshold voltage
- the difference between the first threshold voltage and the second threshold voltage is calculated.
- the absolute value is 0.5V or less.
- MOSFET 1 when the second stress test is performed in which a gate voltage of ⁇ 10 V is applied to gate electrode 27 at a temperature of 150 ° C. for 100 hours, the second stress test is performed.
- the threshold voltage before performing the third stress is the third threshold voltage and the threshold voltage after the second stress test is the fourth threshold voltage
- the difference between the third threshold voltage and the fourth threshold voltage is 0.1 V or less.
- the interface between gate insulating film 15 and gate electrode 27 is defined as first interface 15a, and the first interface among the interfaces between gate insulating film 15 and silicon carbide substrate 10 is used.
- the region facing 15a is the second interface 15b
- the first virtual interface 15a is separated from the first interface 15a by the thickness of the gate insulating film 15 toward the gate electrode 27 along the normal direction of the first interface 15a.
- Interface region R sandwiched between surface 2a and second virtual surface 2b separated from second interface 15b by the thickness of gate insulating film 15 toward silicon carbide substrate 10 along the normal direction of second interface 15b
- the value obtained by dividing the total number of sodium contained in 1 by the area of the first interface 15a is 5 ⁇ 10 10 atoms / cm 2 or less. Thereby, the fluctuation
- the maximum value of the sodium concentration in the region within 10 nm from third main surface 27a opposite to second interface 15b of gate electrode 27 is the sodium concentration in interface region R. It is larger than the maximum value of the concentration, and the maximum value of the sodium concentration in the interface region R is 1 ⁇ 10 16 atoms / cm 3 or less.
- interlayer insulating film 21 that covers third main surface 27a opposite to second interface 15b of gate electrode 27 and that is in contact with gate insulating film 15 is provided.
- source electrode 16 in contact with first main surface 10a of silicon carbide substrate 10.
- the diffusion length of sodium is L T (nm), and the first interface from the surface 21c of the interlayer insulating film 21 opposite to the third main surface 27a in the direction along the normal direction Y of the first interface 15a.
- the maximum value of sodium concentration in the region within 10 nm from second main surface 10b of silicon carbide substrate 10 is larger than the maximum value of sodium concentration in interface region R.
- intermediate substrate 100 including one main surface 21c and the other main surface 10b opposite to one main surface 21c is prepared.
- the sodium block member 7a is disposed in contact with one main surface 21c of the intermediate substrate 100.
- the intermediate substrate 100 is annealed with the sodium block member 7a in contact with the one main surface 21c. After the step of annealing the intermediate substrate 100, the sodium block member 7a is removed from one main surface 21c.
- the intermediate substrate 100 has a first main surface 10a facing one main surface 21c and a second main surface 10b opposite to the first main surface 10a and constituting the other main surface 10b of the intermediate substrate 100.
- Silicon carbide substrate 10 having main surface 10b, gate insulating film 15 partially in contact with first main surface 10a of silicon carbide substrate 10, and first main surface 10a exposed from gate insulating film 15 are in contact with each other.
- Source electrode 16 The diffusion length of sodium with respect to the sodium block member 7a is not more than the diffusion length of sodium with respect to silicon carbide.
- the sodium blocking member 7a can effectively block sodium from entering the one main surface 21c of the intermediate substrate 100 from the outside. Therefore, since the sodium concentration in interface region R can be kept low, fluctuations in the threshold voltage of the silicon carbide semiconductor device can be reduced.
- sodium block member 7a is carbonized on the carbon layer, silicon carbide layer, tantalum carbide layer, silicon layer-coated silicon carbide layer, and carbon layer.
- the silicon layer includes at least one selected from the group consisting of coated layers. Thereby, it can block more effectively that sodium mixes into one main surface 21c of intermediate substrate 100 from the outside.
- the method further includes the step of disposing intermediate substrate holding portion 4 facing the other main surface 10b of intermediate substrate 100.
- the diffusion length of sodium with respect to the intermediate substrate holding part 4 is not more than the diffusion length of sodium with respect to silicon carbide.
- the intermediate substrate holding part 4 can effectively block sodium from being mixed into the main surface 10 b on the other side of the intermediate substrate 100.
- intermediate substrate holding portion 4 is formed on a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and a carbon layer.
- the silicon carbide layer includes at least one selected from the group consisting of coated layers. Thereby, it can block more effectively that sodium is mixed into the main surface 10b on the other side of the intermediate substrate 100.
- the method further includes the step of arranging lid 6 that contacts intermediate substrate holding part 4 and covers sodium blocking member 7a.
- the intermediate substrate 100 is annealed in a state where the intermediate substrate 100 is disposed in the space surrounded by the lid portion 6 and the intermediate substrate holding portion 4.
- the diffusion length of sodium with respect to the lid 6 is not more than the diffusion length of sodium with respect to silicon carbide.
- the lid 6 can effectively block sodium from entering the main surface 21 c on one side of the intermediate substrate 100.
- lid portion 6 includes a carbon layer, a silicon carbide layer, a tantalum carbide layer, a silicon layer coated with a silicon carbide layer, and a silicon carbide on the carbon layer.
- the layer comprises at least one selected from the group consisting of coated layers.
- intermediate substrate 100 including one main surface 21c and the other main surface 10b opposite to one main surface 21c is prepared.
- the first sodium absorbing member 7b is disposed in contact with one main surface 21c of the intermediate substrate 100.
- the intermediate substrate 100 is annealed with the first sodium absorbing member 7b in contact with the one main surface 21c.
- the first sodium absorbing member 7b is removed from the one main surface 21c.
- the intermediate substrate 100 has a first main surface 10a facing one main surface 21c and a second main surface 10b opposite to the first main surface 10a and constituting the other main surface 10b of the intermediate substrate 100.
- the diffusion length of sodium with respect to the first sodium absorbing member 7b is larger than the diffusion length of sodium with respect to silicon carbide. Therefore, even when one main surface 21c of the intermediate substrate 100 is contaminated with sodium, the sodium on the one main surface 21c of the intermediate substrate 100 is absorbed by the first sodium absorbing member 7b, The sodium concentration on one main surface 21c of the intermediate substrate 100 can be effectively reduced. Therefore, since the sodium concentration in interface region R can be kept low, fluctuations in the threshold voltage of the silicon carbide semiconductor device can be reduced.
- first sodium absorbing member 7b includes silicon layer, silicon dioxide layer, silicon layer coated with silicon dioxide layer, and silicon dioxide layer with silicon.
- the layer comprises at least one selected from the group consisting of coated layers.
- the thickness of first sodium absorbing member 7b is 300 ⁇ m or more in a sectional view. Therefore, sodium on one main surface 21c of intermediate substrate 100 can be absorbed more effectively.
- the first sodium absorbing member 7b is in contact with one main surface 21c of the intermediate substrate 100
- the second sodium absorbing member 7c is in contact with the other main surface 10b of the intermediate substrate 100.
- the intermediate substrate 100 is annealed.
- the diffusion length of sodium with respect to the second sodium absorbing member 7c is larger than the diffusion length of sodium with respect to silicon carbide.
- the sodium on the other major surface 10b of the intermediate substrate 100 can be effectively sucked from the second sodium sucking member 7c.
- the method further includes the step of disposing intermediate substrate holding portion 4 facing the other main surface 10b of intermediate substrate 100.
- the diffusion length of sodium with respect to the intermediate substrate holding part 4 is not more than the diffusion length of sodium with respect to silicon carbide.
- the intermediate substrate holding part 4 can effectively block sodium from being mixed into the main surface 10 b on the other side of the intermediate substrate 100.
- intermediate substrate holding portion 4 is formed on a carbon layer, a silicon carbide layer, a tantalum carbide layer, a layer in which a silicon carbide layer is coated on a silicon layer, and a carbon layer.
- the silicon carbide layer includes at least one selected from the group consisting of coated layers. Thereby, it can block more effectively that sodium is mixed into the main surface 10b on the other side of the intermediate substrate 100.
- the method further includes the step of arranging lid 6 that contacts intermediate substrate holding part 4 and covers first sodium sucking member 7b.
- the intermediate substrate 100 is annealed in a state where the intermediate substrate 100 is disposed in the space surrounded by the lid portion 6 and the intermediate substrate holding portion 4.
- the diffusion length of sodium with respect to the lid 6 is not more than the diffusion length of sodium with respect to silicon carbide.
- the lid 6 can effectively block sodium from entering the main surface 21 c on one side of the intermediate substrate 100.
- lid portion 6 includes a carbon layer, a silicon carbide layer, a tantalum carbide layer, a silicon layer coated with a silicon carbide layer, and a silicon carbide on the carbon layer.
- the layer comprises at least one selected from the group consisting of coated layers.
- the first sodium sucking member 7b includes the fourth main surface 7b2 in contact with one main surface 21c, and the fourth main surface 7b2 opposite to the fourth main surface 7b2. 5 after the step of disposing the sodium block member 7a in contact with the fifth main surface 7b1 of the first sodium absorbing member 7b and the step of annealing the intermediate substrate 100, the sodium block member 7a And a step of removing from the intermediate substrate 100. In the step of annealing the intermediate substrate 100, the sodium block member 7a is in contact with the fifth main surface 7b1 of the first sodium absorbing member 7b, and the fourth main surface 7b2 of the first sodium absorbing member 7b is the intermediate substrate 100.
- the intermediate substrate 100 is annealed in contact with the one main surface 21c.
- the diffusion length of sodium with respect to the sodium block member 7a is not more than the diffusion length of sodium with respect to silicon carbide.
- the sodium blocking member 7a can more effectively block sodium from being mixed into the main surface 21c on one side of the intermediate substrate 100.
- sodium block member 7a is carbonized on the carbon layer, silicon carbide layer, tantalum carbide layer, silicon layer-coated silicon carbide layer, and carbon layer.
- the silicon layer includes at least one selected from the group consisting of coated layers. Thereby, it can block more effectively that sodium is mixed into one of the intermediate substrates 100 in the main surface 21c.
- MOSFETs 1 according to Sample 1 to Sample 6 were formed by the same method as that described in the above embodiment except for the following conditions.
- silicon carbide substrate 10 provided with interlayer insulating film 21, gate electrode 27, gate insulating film 15, and source electrode 16 is provided.
- Intermediate body 100 was placed on tray 4.
- the tray was made of carbon, and the cover member 2 made of silicon carbide was provided in contact with the interlayer insulating film 21 of the intermediate body 100.
- the tray was made of carbon.
- the cover member 2 that covers the intermediate body 100 was not provided.
- alloying annealing was performed twice.
- the tray in the first alloying annealing was made of silicon carbide, and the tray in the second alloying annealing was made of carbon.
- the cover member 2 covering the intermediate body 100 was not provided.
- the tray was made of carbon, and cover member 2 made of silicon carbide was provided in contact with interlayer insulating film 21 of intermediate body 100.
- the 1st sodium absorption member 7b which consists of silicon was provided in contact with one main surface 21c of the intermediate body 100.
- the intermediate body 100 and the first sodium absorbing member 7b are arranged in the carbon tray 4, and the carbon lid 6 is arranged so as to cover the first sodium absorbing member 7b.
- first sodium absorbing member 7b made of silicon is provided in contact with one main surface 21c of intermediate body 100, and silicon is provided in contact with the other main surface 10b.
- the 2nd sodium absorption member 7c which consists of was provided.
- the intermediate body 100, the first sodium absorbing member 7b, and the second sodium absorbing member 7c are arranged in the carbon tray 4, and the carbon lid 6 is arranged so as to cover the first sodium absorbing member 7b. .
- Three samples 5 and 6 were prepared.
- an alloying annealing process was performed on samples 1 to 6.
- the alloying annealing was performed in a state where the cover member 2 made of silicon carbide was in contact with the interlayer insulating film 21 of the intermediate body 100.
- alloying annealing was performed in a state where the first sodium absorbing member 7b made of silicon was in contact with the interlayer insulating film 21 of the intermediate body 100.
- the alloying annealing is performed in a state where the cover member 2 made of silicon carbide is not provided and the interlayer insulating film 21 and the source electrode 16 are not covered by the cover member 2. did.
- the sample 2 and the sample 3 were subjected to the lamp annealing process and the sintering process.
- the intermediate 100 was heated at a temperature of 740 ° C. for 30 seconds.
- the sintering process the intermediate 100 was heated at a temperature of 400 ° C. for 15 minutes. Sample 1, Sample 4, Sample 5, and Sample 6 were not subjected to the lamp annealing process and sintering process.
- gate electrode 27 and interlayer insulation are set so that N 0 ⁇ L T / x is 1.52 ⁇ 10 20 or more.
- the temperature and time of the heat treatment performed on the intermediate 100 including the film 21 was controlled.
- an intermediate including gate electrode 27 and interlayer insulating film 21 is set so that N 0 ⁇ L T / x is less than 1.52 ⁇ 10 20.
- the temperature and time of the heat treatment performed on the body 100 was controlled.
- Sample 1 was manufactured under approximately the same manufacturing conditions as sample 4, but different equipment was used in most manufacturing steps.
- the TEG shown in FIG. 13 was formed on the same wafer on which the MOSFETs according to Sample 1 to Sample 6 were formed.
- the TEG was created to measure the total number of sodium in the interface area.
- a silicon dioxide film 15 was provided on a silicon carbide substrate 10, and polysilicon 27 was provided on the silicon dioxide film.
- the silicon dioxide film 15 corresponds to the gate insulating film 15 of the MOSFET 1
- the polysilicon 27 corresponds to the gate electrode 27 of the MOSFET 1.
- the thickness of the gate insulating film 15 was 45 nm, and the thickness of the polysilicon 27 was 300 nm. 2.
- the amount of fluctuation of the threshold voltage of MOSFET 1 according to samples 1 to 6 was measured.
- the first threshold voltage before the gate bias stress was applied to the gate electrode 27 of the MOSFET 1 according to the samples 1 to 6 was measured.
- the definition of the threshold voltage is as described in the embodiment.
- a gate bias stress was applied to the MOSFETs 1 according to the samples 1 to 6.
- a gate bias stress a gate voltage of ⁇ 5 V was applied to the gate electrode 27 at a temperature of 175 ° C. for 100 hours.
- the second threshold voltage was measured.
- the variation amount of the threshold voltage was calculated by subtracting the second threshold voltage from the first threshold voltage.
- the third threshold voltage before the gate bias stress was applied to the gate electrode 27 of the MOSFET 1 according to the samples 1 to 6 was measured.
- a gate voltage of ⁇ 10 V was applied to the gate electrode 27 at a temperature of 150 ° C. for 100 hours.
- the fourth threshold voltage was measured.
- the variation amount of the threshold voltage was calculated by subtracting the fourth threshold voltage from the third threshold voltage.
- the sodium concentration was measured using the TEGs related to Sample 1 to Sample 6.
- the sodium concentration was measured by digging the TEG from the surface 27a of the polysilicon 27 toward the silicon carbide substrate 10 by SIMS.
- the silicon dioxide film 15 and the silicon carbide substrate 10 are separated from the first interface 15a between the polysilicon 27 and the silicon dioxide film 15 by a thickness (45 nm) away from the first interface 15a toward the surface 27a of the polysilicon 27.
- the total concentration of sodium atoms in the interface region R was calculated by integrating the sodium concentration from the second interface 15b to a position separated from the silicon carbide substrate 10 by the thickness of the silicon dioxide film 15 (45 nm).
- the iron concentration, nitrogen concentration, phosphorus concentration and hydrogen concentration in the interface region R were also measured. 3.
- the vicinity of first interface 15a between silicon dioxide film 15 and polysilicon 27 and the second interface 15b between silicon dioxide film 15 and silicon carbide substrate 10 are used.
- the Na concentration was as high as about 1 ⁇ 10 17 atoms / cm 3 or more.
- the maximum value of the Na concentration in the interface region R was as low as about 1 ⁇ 10 16 atoms / cm 3 or less.
- the maximum value of Na concentration in a region within 10 nm from the surface 27a of the polysilicon 27 was as high as about 1 ⁇ 10 18 atoms / cm 3 or more.
- no significant difference was found in the concentrations of iron, nitrogen, phosphorus, and hydrogen, which are impurities other than sodium.
- the second threshold voltage of the MOSFETs according to Sample 1 to Sample 6 was smaller than the first threshold voltage.
- the threshold voltage fluctuation amounts of the MOSFETs according to Sample 1, Sample 4, Sample 5 and Sample 6 in which the total number of Na is 5 ⁇ 10 10 atoms / cm 2 or less are 0.01 V, 0.13 V, and 0.01 to 0, respectively. 0.03 V and 0.00 to 0.01 V, both of which were 0.5 V or less.
- the amount of fluctuation of the threshold voltage of the MOSFET according to Sample 3 in which the total number of Na exceeds 5 ⁇ 10 10 atoms / cm 2 is 2.34V, which is a large value.
- the second threshold voltage of the MOSFET according to sample 3 was a negative value.
- FIG. 26 is a plot of Samples 1, 4, 5, and 6 in Table 2 with the vertical axis representing the amount of variation in threshold voltage and the horizontal axis representing the total number of Na in the interface region R.
- Diamonds indicate samples 1 and 4
- squares indicate sample 5
- triangles indicate sample 6.
- Samples 1 and 4 are alloyed and annealed using a cover member (sodium block member) made of silicon carbide.
- samples 5 and 6 are annealed using a cover member (sodium absorbing member) made of silicon.
- Sample 5 is a single-sided cover
- sample 6 is a double-sided cover.
- the difference (variation) in the amount of variation in threshold voltage between samples 1 and 4 is 0.12 V (difference 31), whereas three samples between samples 5 and 6
- the difference in the amount of variation in the threshold voltage of the three samples was 0.02 V (difference 32) and 0.01 V (difference 33), respectively.
- sample 5 using a single-sided cover member made of silicon is a cover member made of silicon carbide. It was confirmed that Samples 1 and 4 using the sample showed the same total Na amount and variation amount of the threshold voltage. In addition, when using a double-sided cover member made of silicon, it was confirmed that the total amount of Na and the amount of change in threshold voltage were smaller than using a single-sided cover member made of silicon and a cover member made of silicon carbide. Further, it has been confirmed that the samples 5 and 6 using the cover member made of silicon have less variation in the variation amount of the threshold voltage than the samples 1 and 4 using the cover member made of silicon carbide. In the case of Samples 5 and 6, Na is absorbed using a cover member made of silicon, so it is estimated that the sample is strong against disturbance factors.
- the fourth threshold voltage of the MOSFETs according to Sample 1 to Sample 6 was smaller than the third threshold voltage.
- the variation amounts of the threshold voltages of the MOSFETs according to Sample 1, Sample 4, Sample 5 and Sample 6 in which the total number of Na is 5 ⁇ 10 10 atoms / cm 2 or less are 0.02 V, 0.10 V, and 0.01 to 0, respectively. 0.04 V and 0.00 to 0.01 V, both of which were 0.1 V or less.
- the fluctuation amounts of the threshold voltages of the MOSFETs related to Sample 2 and Sample 3 in which the total number of Na exceeds 5 ⁇ 10 10 atoms / cm 2 are 2.55 V and 3.39 V, respectively, which are large values.
- the 2nd threshold voltage of MOSFET concerning sample 2 and sample 3 became a negative value.
- the Na total number and the threshold voltage fluctuation amount of Sample 1 were smaller than the Na total number and threshold voltage fluctuation amount of Sample 4.
- Sample 1 was manufactured under nearly the same manufacturing conditions as Sample 4, but different equipment was used in most manufacturing processes. Therefore, it is considered that there is a difference in the amount of Na adhering to the surface 21c of the interlayer insulating film 21, and as a result, a difference in the variation amount of the threshold voltage occurs.
- FIG. 27 is a plot of Samples 1, 4, 5 and 6 in Table 3 with the vertical axis representing the amount of variation in threshold voltage and the horizontal axis representing the total number of Na in the interface region R.
- Diamonds indicate samples 1 and 4
- squares indicate sample 5
- triangles indicate sample 6.
- Samples 1 and 4 are alloyed and annealed using a cover member (sodium block member) made of silicon carbide.
- samples 5 and 6 are annealed using a cover member (sodium absorbing member) made of silicon.
- Sample 5 is a single-sided cover
- sample 6 is a double-sided cover.
- the difference (variation) in the amount of variation in threshold voltage between samples 1 and 4 is 0.08 V (difference 41), whereas three samples between samples 5 and 3 between samples 6
- the difference in the amount of variation in the threshold voltage of the two samples was 0.03 V (difference 42) and 0.01 V (difference 43), respectively.
- the sample 5 using the single-sided cover member made of silicon has a cover made of silicon carbide. It was confirmed that Samples 1 and 4 using the member showed the same Na total number and threshold voltage fluctuation amount. In addition, when using a double-sided cover member made of silicon, it was confirmed that the total amount of Na and the amount of change in threshold voltage were smaller than using a single-sided cover member made of silicon and a cover member made of silicon carbide. Further, it has been confirmed that the samples 5 and 6 using the cover member made of silicon have less variation in the variation amount of the threshold voltage than the samples 1 and 4 using the cover member made of silicon carbide.
- MOSFET 1 in which the total number of sodium in the interface region R is 5 ⁇ 10 10 atoms / cm 2 or less can effectively reduce the variation amount of the threshold voltage.
- SYMBOLS 1 Silicon carbide semiconductor device (MOSFET), 2 cover member, 2a 1st virtual surface, 2b 2nd virtual surface, 4 Intermediate board
Abstract
Description
以下、図面に基づいて本発明の実施の形態について説明する。なお、以下の図面において同一または相当する部分には同一の参照番号を付しその説明は繰返さない。また、本明細書中の結晶学的記載においては、個別方位を[]、集合方位を<>、個別面を()、集合面を{}でそれぞれ示している。また、負の指数については、結晶学上、”-”(バー)を数字の上に付けることになっているが、本明細書中では、数字の前に負の符号を付けている。また角度の記載には、全方位角を360度とする系を用いている。
まず、本発明の一実施の形態に係る炭化珪素半導体装置としてのMOSFET1の構成について説明する。
図15を参照して、中間基板にカバー部材を搭載する工程において、中間基板100の一方の主面21cに接してナトリウムブロック部材7aが配置される。ナトリウムブロック部材7aは、中間基板100の一方主面21cに接する第6の主面7a2と、第6の主面7a2と反対側の第7の主面7a1とを有する。ナトリウムブロック部材7aの第6の主面7a2は、中間基板100の一方の主面21cの全面を覆うように配置される。好ましくは、断面視(中間基板100の他方の主面10bと平行な方向に沿って見た視野)において、ナトリウムブロック部材7aの幅は、中間基板100の幅以上である。
図18を参照して、中間基板にカバー部材を搭載する工程において、中間基板100の一方の主面21cに接して第1のナトリウム吸取部材7bが配置される。第1のナトリウム吸取部材7bに対するナトリウムの拡散長は、炭化珪素に対するナトリウムの拡散長よりも大きい。第1のナトリウム吸取部材7bを構成する材料は、たとえば珪素である。好ましくは、第1のナトリウム吸取部材7bは、珪素層、二酸化珪素層、珪素層上に二酸化珪素層がコーティングされた層および二酸化珪素層上に珪素層がコーティングされた層からなる群から選択される少なくとも1つを含む。珪素は、単結晶であってもよいし、多結晶であってもよいし、アモルファスであってもよいし、これらの組み合わせであってもよい。好ましくは、断面視において、第1のナトリウム吸取部材7bの幅は、中間基板100の幅以上である。
本実施例では、MOSFET1の界面領域RにおけるNaの総数と、閾値電圧の変動量との関係について調査した。まず、サンプル1~サンプル6に係るMOSFET1を、以下の条件を除き、上記実施の形態に記載の方法と同様の方法で作成した。図10および図11に示すように、合金化アニール工程が実施される前に、層間絶縁膜21と、ゲート電極27と、ゲート絶縁膜15と、ソース電極16とが設けられた炭化珪素基板10(中間体100)をトレー4に配置した。サンプル1の製造工程においては、トレーをカーボン製とし、かつ中間体100の層間絶縁膜21に接して炭化珪素からなるカバー部材2を設けた。サンプル2の製造工程においては、トレーをカーボン製とした。中間体100を覆うカバー部材2を設けなかった。サンプル3の製造工程においては、合金化アニールを2回実施した。1回目の合金化アニールにおけるトレーを炭化珪素製とし、2回目の合金化アニールにおけるトレーをカーボン製とした。1回目および2回目の合金化アニールにおいて、中間体100を覆うカバー部材2を設けなかった。サンプル4の製造工程においては、トレーをカーボン製とし、かつ中間体100の層間絶縁膜21に接して炭化珪素からなるカバー部材2を設けた。サンプル5の製造工程においては、図22に示すように、中間体100の一方の主面21cに接して珪素からなる第1のナトリウム吸取部材7bを設けた。中間体100および第1のナトリウム吸取部材7bをカーボン製のトレー4内に配置し、第1のナトリウム吸取部材7bを覆うようにカーボン製の蓋部6を配置した。サンプル6の製造工程においては、図23に示すように、中間体100の一方の主面21cに接して珪素からなる第1のナトリウム吸取部材7bを設け、かつ他方の主面10bに接して珪素からなる第2のナトリウム吸取部材7cを設けた。中間体100、第1のナトリウム吸取部材7bおよび第2のナトリウム吸取部材7cをカーボン製のトレー4内に配置し、第1のナトリウム吸取部材7bを覆うようにカーボン製の蓋部6を配置した。サンプル5およびサンプル6をそれぞれ3つずつ準備した。
2.実験
サンプル1~サンプル6に係るMOSFET1の閾値電圧の変動量を測定した。具体的には、まず、サンプル1~サンプル6に係るMOSFET1のゲート電極27にゲートバイアスストレスが印加される前の第1の閾値電圧を測定した。閾値電圧の定義は実施の形態で説明した通りである。次に、サンプル1~サンプル6に係るMOSFET1に対してゲートバイアスストレスを印加した。ゲートバイアスストレスとして、175℃の温度下において、ゲート電極27に対して-5Vのゲート電圧を100時間印加した。ゲートバイアスストレス印加後、第2の閾値電圧を測定した。第1の閾値電圧から第2の閾値電圧を差し引き閾値電圧の変動量を計算した。同様に、サンプル1~サンプル6に係るMOSFET1のゲート電極27にゲートバイアスストレスが印加される前の第3の閾値電圧を測定した。その後、150℃の温度下において、ゲート電極27に対して-10Vのゲート電圧を100時間印加した。ゲートバイアスストレス印加後、第4の閾値電圧を測定した。第3の閾値電圧から第4の閾値電圧を差し引き閾値電圧の変動量を計算した。
3.結果
図14を参照して、ナトリウム濃度とポリシリコン表面からの深さとの関係について説明する。サンプル1~サンプル3に関しては、図14の横軸の位置0はポリシリコン27の表面27aに対応し、サンプル4に関しては、図14の横軸の位置αがポリシリコン27の表面27aに対応する。サンプル1~サンプル4の各々に関して、図14の横軸の位置0.3は二酸化珪素膜15と炭化珪素基板10との第2の界面15bに対応する。サンプル5およびサンプル6に関しては、ナトリウム濃度のみを表2および表3に示し、図14において濃度プロファイルは省略する。
Claims (22)
- 第1の主面と、前記第1の主面と反対側の第2の主面とを有する炭化珪素基板と、
前記炭化珪素基板の前記第1の主面に接して設けられたゲート絶縁膜と、
前記炭化珪素基板との間に前記ゲート絶縁膜を挟むように前記ゲート絶縁膜上に設けられたゲート電極とを備え、
175℃の温度下において、前記ゲート電極に対して-5Vのゲート電圧を100時間印加する第1のストレス試験を行う場合に、前記第1のストレス試験を行う前の閾値電圧を第1の閾値電圧とし、前記第1のストレス試験を行った後の閾値電圧を第2の閾値電圧とした場合、前記第1の閾値電圧と前記第2の閾値電圧との差の絶対値は、0.5V以下である、炭化珪素半導体装置。 - 150℃の温度下において、前記ゲート電極に対して-10Vのゲート電圧を100時間印加する第2のストレス試験を行う場合に、前記第2のストレス試験を行う前の閾値電圧を第3の閾値電圧とし、前記第2のストレス試験を行った後の閾値電圧を第4の閾値電圧とした場合、前記第3の閾値電圧と前記第4の閾値電圧との差の絶対値は、0.1V以下である、請求項1に記載の炭化珪素半導体装置。
- 前記ゲート絶縁膜と前記ゲート電極との界面を第1の界面とし、前記ゲート絶縁膜と前記炭化珪素基板との界面のうち、前記第1の界面と対向する領域を第2の界面とした場合、前記第1の界面の法線方向に沿って前記第1の界面から前記ゲート絶縁膜の厚みだけ前記ゲート電極側に離れた第1仮想面と、前記第2の界面の法線方向に沿って前記第2の界面から前記ゲート絶縁膜の厚みだけ前記炭化珪素基板側に離れた第2仮想面とに挟まれた界面領域に含まれるナトリウムの総数を前記第1の界面の面積で除した値は、5×1010atoms/cm2以下である、請求項1または請求項2に記載の炭化珪素半導体装置。
- 前記ゲート電極の前記第2の界面とは反対側の第3の主面から10nm以内の領域におけるナトリウム濃度の最大値は、前記界面領域におけるナトリウム濃度の最大値よりも大きく、
前記界面領域におけるナトリウム濃度の最大値は、1×1016atoms/cm3以下である、請求項3に記載の炭化珪素半導体装置。 - 前記ゲート電極の前記第2の界面とは反対側の第3の主面を覆い、かつ前記ゲート絶縁膜に接して設けられた層間絶縁膜と、
前記炭化珪素基板の前記第1の主面に接するソース電極とをさらに備え、
ナトリウムの拡散長をLT(nm)とし、前記第1の界面の法線方向に沿った方向における前記第3の主面とは反対側の前記層間絶縁膜の表面から前記第1の界面までの距離をx(nm)とし、かつ前記層間絶縁膜の前記表面におけるナトリウム濃度をN0(cm-3)とした場合に、N0×LT/x<1.52×1020となるように、前記ソース電極をアニールする工程以降に前記ゲート電極および前記層間絶縁膜に対して行われる熱処理の温度および時間が制御された、請求項3または請求項4に記載の炭化珪素半導体装置。 - 前記炭化珪素基板の前記第2の主面から10nm以内の領域におけるナトリウム濃度の最大値は、前記界面領域におけるナトリウム濃度の最大値よりも大きい、請求項3~請求項5のいずれか1項に記載の炭化珪素半導体装置。
- 一方の主面と、前記一方の主面と反対側の他方の主面とを含む中間基板を準備する工程と、
前記中間基板の前記一方の主面に接してナトリウムブロック部材を配置する工程と、
前記ナトリウムブロック部材が前記一方の主面に接した状態で前記中間基板をアニールする工程と、
前記中間基板をアニールする工程後に、前記ナトリウムブロック部材を前記一方の主面から除去する工程とを備え、
前記中間基板は、前記一方の主面と対向する第1の主面と、前記第1の主面とは反対側であって、前記中間基板の前記他方の主面を構成する第2の主面と有する炭化珪素基板と、前記炭化珪素基板の前記第1の主面と部分的に接するゲート絶縁膜と、前記ゲート絶縁膜から露出している前記第1の主面に接するソース電極とを含み、
前記ナトリウムブロック部材に対するナトリウムの拡散長は、炭化珪素に対するナトリウムの拡散長以下である、炭化珪素半導体装置の製造方法。 - 前記ナトリウムブロック部材は、炭素層、炭化珪素層、炭化タンタル層、珪素層上に炭化珪素層がコーティングされた層および炭素層上に炭化珪素層がコーティングされた層からなる群から選択される少なくとも1つを含む、請求項7に記載の炭化珪素半導体装置の製造方法。
- 前記中間基板の前記他方の主面と対向する中間基板保持部を配置する工程をさらに備え、
前記中間基板保持部に対するナトリウムの拡散長は、前記炭化珪素に対するナトリウムの拡散長以下である、請求項7または請求項8に記載の炭化珪素半導体装置の製造方法。 - 前記中間基板保持部は、炭素層、炭化珪素層、炭化タンタル層、珪素層上に炭化珪素層がコーティングされた層および炭素層上に炭化珪素層がコーティングされた層からなる群から選択される少なくとも1つを含む、請求項9に記載の炭化珪素半導体装置の製造方法。
- 前記中間基板保持部と接し、かつ前記ナトリウムブロック部材を覆う蓋部を配置する工程をさらに備え、
前記中間基板をアニールする工程において、前記蓋部および前記中間基板保持部によって囲まれた空間に前記中間基板が配置された状態で前記中間基板がアニールされ、
前記蓋部に対するナトリウムの拡散長は、前記炭化珪素に対するナトリウムの拡散長以下である、請求項9または請求項10に記載の炭化珪素半導体装置の製造方法。 - 前記蓋部は、炭素層、炭化珪素層、炭化タンタル層、珪素層上に炭化珪素層がコーティングされた層および炭素層上に炭化珪素層がコーティングされた層からなる群から選択される少なくとも1つを含む、請求項11に記載の炭化珪素半導体装置の製造方法。
- 一方の主面と、前記一方の主面と反対側の他方の主面とを含む中間基板を準備する工程と、
前記中間基板の前記一方の主面に接して第1のナトリウム吸取部材を配置する工程と、
前記第1のナトリウム吸取部材が前記一方の主面に接した状態で前記中間基板をアニールする工程と、
前記中間基板をアニールする工程後に、前記第1のナトリウム吸取部材を前記一方の主面から除去する工程とを備え、
前記中間基板は、前記一方の主面と対向する第1の主面と、前記第1の主面とは反対側であって、かつ前記中間基板の前記他方の主面を構成する第2の主面と有する炭化珪素基板と、前記炭化珪素基板の前記第1の主面と部分的に接するゲート絶縁膜と、前記ゲート絶縁膜から露出している前記第1の主面に接するソース電極とを含み、
前記第1のナトリウム吸取部材に対するナトリウムの拡散長は、炭化珪素に対するナトリウムの拡散長よりも大きい、炭化珪素半導体装置の製造方法。 - 前記第1のナトリウム吸取部材は、珪素層、二酸化珪素層、珪素層上に二酸化珪素層がコーティングされた層および二酸化珪素層上に珪素層がコーティングされた層からなる群から選択される少なくとも1つを含む、請求項13に記載の炭化珪素半導体装置の製造方法。
- 断面視において、前記第1のナトリウム吸取部材の厚みは300μm以上である、請求項13または請求項14に記載の炭化珪素半導体装置の製造方法。
- 前記中間基板をアニールする工程前に、前記中間基板の前記他方の主面に接して第2のナトリウム吸取部材を配置する工程と、
前記中間基板をアニールする工程後に、前記第2のナトリウム吸取部材を前記他方の主面から除去する工程とをさらに備え、
前記中間基板をアニールする工程において、前記第1のナトリウム吸取部材が前記中間基板の前記一方の主面に接し、かつ前記第2のナトリウム吸取部材が前記中間基板の前記他方の主面に接した状態で、前記中間基板がアニールされ、
前記第2のナトリウム吸取部材に対するナトリウムの拡散長は、炭化珪素に対するナトリウムの拡散長よりも大きい、請求項13~請求項15のいずれか1項に記載の炭化珪素半導体装置の製造方法。 - 前記中間基板の前記他方の主面と対向する中間基板保持部を配置する工程をさらに備え、
前記中間基板保持部に対するナトリウムの拡散長は、前記炭化珪素に対するナトリウムの拡散長以下である、請求項13~請求項16のいずれか1項に記載の炭化珪素半導体装置の製造方法。 - 前記中間基板保持部は、炭素層、炭化珪素層、炭化タンタル層、珪素層上に炭化珪素層がコーティングされた層および炭素層上に炭化珪素層がコーティングされた層からなる群から選択される少なくとも1つを含む、請求項17に記載の炭化珪素半導体装置の製造方法。
- 前記中間基板保持部と接し、かつ前記第1のナトリウム吸取部材を覆う蓋部を配置する工程をさらに備え、
前記中間基板をアニールする工程において、前記蓋部および前記中間基板保持部によって囲まれた空間に前記中間基板が配置された状態で前記中間基板がアニールされ、
前記蓋部に対するナトリウムの拡散長は、前記炭化珪素に対するナトリウムの拡散長以下である、請求項17または請求項18に記載の炭化珪素半導体装置の製造方法。 - 前記蓋部は、炭素層、炭化珪素層、炭化タンタル層、珪素層上に炭化珪素層がコーティングされた層および炭素層上に炭化珪素層がコーティングされた層からなる群から選択される少なくとも1つを含む、請求項19に記載の炭化珪素半導体装置の製造方法。
- 前記第1のナトリウム吸取部材は、前記一方の主面に接する第4の主面と、前記第4の主面と反対側の第5の主面とを含み、
前記第1のナトリウム吸取部材の前記第5の主面に接してナトリウムブロック部材を配置する工程と、
前記中間基板をアニールする工程後に、前記ナトリウムブロック部材を前記中間基板から除去する工程とをさらに備え、
前記中間基板をアニールする工程において、前記ナトリウムブロック部材が前記第1のナトリウム吸取部材の前記第5の主面に接し、かつ前記第1のナトリウム吸取部材の前記第4の主面が前記中間基板の前記一方の主面と接した状態で前記中間基板がアニールされ、
前記ナトリウムブロック部材に対するナトリウムの拡散長は、炭化珪素に対するナトリウムの拡散長以下である、請求項13~請求項20のいずれか1項に記載の炭化珪素半導体装置の製造方法。 - 前記ナトリウムブロック部材は、炭素層、炭化珪素層、炭化タンタル層、珪素層上に炭化珪素層がコーティングされた層および炭素層上に炭化珪素層がコーティングされた層からなる群から選択される少なくとも1つを含む、請求項21に記載の炭化珪素半導体装置の製造方法。
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11330090A (ja) * | 1998-05-18 | 1999-11-30 | Rohm Co Ltd | 縦型二重拡散mosfetおよびその製造方法 |
JP2006222210A (ja) * | 2005-02-09 | 2006-08-24 | Fuji Electric Device Technology Co Ltd | 半導体装置 |
JP2007287992A (ja) * | 2006-04-18 | 2007-11-01 | Fuji Electric Holdings Co Ltd | 炭化珪素半導体装置およびその製造方法 |
JP2010502031A (ja) * | 2006-09-01 | 2010-01-21 | エヌエックスピー ビー ヴィ | 炭化ケイ素mosfetの反転層移動度を改善する方法 |
JP2011199060A (ja) * | 2010-03-19 | 2011-10-06 | Toshiba Corp | 半導体装置及びその製造方法 |
JP2013175593A (ja) * | 2012-02-24 | 2013-09-05 | Rohm Co Ltd | 半導体装置およびその製造方法 |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6232648A (ja) | 1985-07-30 | 1987-02-12 | イ−トン コ−ポレ−シヨン | 高密度高電圧fet |
JPH11345964A (ja) | 1998-05-29 | 1999-12-14 | Rohm Co Ltd | Mosfetおよびその製造方法 |
WO2007034841A1 (ja) * | 2005-09-21 | 2007-03-29 | Mitsubishi Chemical Corporation | 有機半導体材料及び有機電界効果トランジスタ |
CA2636776A1 (en) | 2006-01-30 | 2007-08-02 | Sumitomo Electric Industries, Ltd. | Method of manufacturing silicon carbide semiconductor device |
JP2012089613A (ja) * | 2010-10-18 | 2012-05-10 | Sumitomo Electric Ind Ltd | 炭化珪素基板を有する複合基板の製造方法 |
DE202012013565U1 (de) * | 2011-07-20 | 2017-11-14 | Sumitomo Electric Industries, Ltd. | Siliziumkarbidsubstrat und Halbleitervorrichtung |
JP2014170891A (ja) * | 2013-03-05 | 2014-09-18 | Sumitomo Electric Ind Ltd | 炭化珪素基板、炭化珪素基板の製造方法および炭化珪素半導体装置の製造方法 |
JP5557304B1 (ja) * | 2013-09-26 | 2014-07-23 | 国立大学法人東北大学 | 有機半導体素子及びそれを備えたcmis半導体装置 |
US9236433B2 (en) * | 2013-10-10 | 2016-01-12 | Cree, Inc. | Semiconductor devices in SiC using vias through N-type substrate for backside contact to P-type layer |
DE112015005348T5 (de) * | 2014-11-27 | 2017-08-10 | Sumitomo Electric Industries, Ltd. | Siliziumkarbid-Substrat, Verfahren zur Herstellung desselben und Verfahren zur Hersteliung einer Siliziumkarbid-Halbleitervorrichtung |
JP2016213419A (ja) * | 2015-05-13 | 2016-12-15 | 住友電気工業株式会社 | 炭化珪素半導体装置 |
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Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11330090A (ja) * | 1998-05-18 | 1999-11-30 | Rohm Co Ltd | 縦型二重拡散mosfetおよびその製造方法 |
JP2006222210A (ja) * | 2005-02-09 | 2006-08-24 | Fuji Electric Device Technology Co Ltd | 半導体装置 |
JP2007287992A (ja) * | 2006-04-18 | 2007-11-01 | Fuji Electric Holdings Co Ltd | 炭化珪素半導体装置およびその製造方法 |
JP2010502031A (ja) * | 2006-09-01 | 2010-01-21 | エヌエックスピー ビー ヴィ | 炭化ケイ素mosfetの反転層移動度を改善する方法 |
JP2011199060A (ja) * | 2010-03-19 | 2011-10-06 | Toshiba Corp | 半導体装置及びその製造方法 |
JP2013175593A (ja) * | 2012-02-24 | 2013-09-05 | Rohm Co Ltd | 半導体装置およびその製造方法 |
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