Semiconductor device, electronic apparatus, and system

Abstract

The invention provides a semiconductor device, an electronic apparatus, and a system, which are useful for power devices and the like and have excellent electrical characteristics. A semiconductor device is used, for example, to be applied to a power device or the like, and includes a laminated structure that includes a first semiconductor layer containing a crystalline oxide containing germanium or a mixed crystal thereof as a main component and a second semiconductor layer containing a crystalline oxide containing germanium or a mixed crystal thereof as a main component. A semiconductor device in which a second semiconductor layer having the same crystal structure as the first semiconductor layer is laminated directly or via another layer, the semiconductor device further comprising: a Schottky electrode that is Schottky-bonded to the second semiconductor layer; and an ohmic electrode ohmically bonded to the first semiconductor layer.

Description

Technical Field

[0001] This invention relates to semiconductor devices, electronic devices and systems thereof that are useful as power devices and the like. Background Technology

[0002] In recent years, rutile-structured germanium dioxide (r-GeO2) has attracted attention as a promising ultra-wide bandgap (UWBG) semiconductor for future power electronic devices. With a bandgap of 4.68 eV, r-GeO2 can realize both n-type and p-type semiconductors and can be fabricated at low cost, making it highly anticipated as a next-generation semiconductor device.

[0003] Non-Patent Document 1, Patent Document 1, Patent Document 2, and Patent Document 3 have investigated laminated structures in which an r-GeO2 crystalline film is deposited on an r-TiO2 (001) substrate. However, regarding Non-Patent Document 1, after review of Non-Patent Document 1, Non-Patent Document 2 was proposed as an Erratum (Non-Patent Document 2), which determined that the grains (abnormal grains) described in Non-Patent Document 1 and Patent Document 1 are rutile-type germanium dioxide crystals, and the remaining portion is an amorphous phase. That is, only a majority of the amorphous phase is formed, and even if a crystalline phase is formed, only a portion of the grains are formed. Therefore, a strategy to manufacture a crystalline film with excellent crystallinity that can be electrically controlled is desired.

[0004] Furthermore, in Non-Patent Literature 3, an alloy thin film of r-(Ge,Sn)O2 was prepared by mixing easily crystallizable tin dioxide (r-SnO2) with r-GeO2, and n-type conductivity was confirmed. However, since the band gap of r-SnO2 is 3.7 eV, which is smaller than that of r-GeO2, the characteristics of r-GeO2 cannot be utilized in the r-(Ge,Sn)O2 alloy thin film. In addition, the composition of Ge and Sn is difficult to control.

[0005] Furthermore, in Non-Patent Literature 4, a Schottky barrier diode (SBD) was fabricated by mixing easily crystallizable tin dioxide and r-GeO2 to prepare an alloy thin film of r-(Ge,Sn)O2. However, in SBDs using r-(Ge,Sn)O2 alloy thin films, the composition is difficult to control, and the electrical characteristics are also difficult to control, leading to problems such as damage to semiconductor properties, making it difficult to realize an industrially useful semiconductor device. Therefore, a strategy using an industrially useful semiconductor device employing an r-GeO2 single crystal film is desired.

[0006] Prior art literature

[0007] Non-patent literature

[0008] Non-patent literature 1: H.Takane, K.Kaneko, "Establishment of a growth route ofcrystallized rutile GeO2 thin film (≥1μm / h) and its structural properties", Applied Physics Letters Vol.119, pp.062104 (1-6) (2021).

[0009] Non-patent literature 2: H.Takane, K.Kaneko, Erratum: "Establishment of a growthroute of crystallized rutile GeO2 thin film (≥1μm / h) and its structural properties", Applied Physics Letters Vol.120, 099903 (1-3) (2022).

[0010] Non-patent literature 3: H. Takane, et al., “Band-gap engineering of rutile-structured SnO2-GeO2-SiO2 alloy system”, PHYSICAL REVIEW MATERIALS 6, 084604 (2022).

[0011] Non-patent literature 4: H. Takane, et al., "Rutile-type Ge x Sn 1-x O2 alloy layerslatticematched to TiO2 substrates for device applications”, Applied PhysicsExpress 17, 011008 (2024).

[0012] Patent documents

[0013] Patent Document 1: International Publication No. 2023 / 008454

[0014] Patent Document 2: International Publication No. 2023 / 008453

[0015] Patent document 3: International Publication No. 2023 / 008452. Summary of the Invention

[0016] -The problem the invention aims to solve-

[0017] The purpose of this invention is to provide a GeO2 semiconductor device with excellent electrical characteristics.

[0018] -Methods for solving problems-

[0019] To achieve the aforementioned objectives, the inventors conducted in-depth research and developed a novel atomization CVD device using a guide partition. Using this device, a semiconductor device was successfully fabricated. This semiconductor device comprises a stacked structure. On a first semiconductor layer containing a crystalline oxide primarily composed of germanium or a mixture thereof, a second semiconductor layer having the same crystal structure as the first semiconductor layer is stacked directly or alternately with other layers. The semiconductor device further comprises: a Schottky electrode, Schottky-bonded to the second semiconductor layer; and an ohmic electrode, ohmically bonded to the first semiconductor layer. The resulting semiconductor device exhibits excellent crystallinity and excellent electrical properties, and it was found that such a semiconductor device can solve the aforementioned existing problems in one fell swoop.

[0020] Furthermore, after gaining the above understanding, the inventors conducted further and repeated research, thereby completing this invention.

[0021] That is, the present invention relates to the following invention.

[0022] [1] A semiconductor device comprising a stacked structure having a second semiconductor layer having the same crystal structure as the first semiconductor layer, either directly or across other layers, on a first semiconductor layer containing a crystalline oxide comprising germanium or a mixture thereof as a main component, the semiconductor device being characterized in that it further comprises: a Schottky electrode, Schottky-bonded to the second semiconductor layer; and an ohmic electrode, ohmic-bonded to the first semiconductor layer.

[0023] [2] In the semiconductor device described in [1], the second semiconductor layer contains a crystalline oxide comprising germanium or a mixture thereof as a main component.

[0024] [3] In the semiconductor device described in [1], the first semiconductor layer has a rutile structure.

[0025] [4] In the semiconductor device described in [1], the first semiconductor layer contains a dopant.

[0026] [5] In the semiconductor device described in [4], the dopant comprises an element of group 15 of the periodic table.

[0027] [6] In the semiconductor device described in [1], the crystalline oxide contains germanium dioxide as a main component.

[0028] [7] In the semiconductor device described in [1], the thickness of the first semiconductor layer is 500 nm or more.

[0029] [8] In the semiconductor device described in [1], the thickness of the second semiconductor layer is 1.0 μm or more.

[0030] [9] In the semiconductor device described in [1], the area of ​​the first semiconductor layer is 100 mm². 2 above.

[0031]

[10] In the semiconductor device described in [1], the carrier concentration of the first semiconductor layer is 1 × 10⁻⁶. 19 / cm 3 above.

[0032]

[11] In the semiconductor device described in [1], the carrier concentration of the second semiconductor layer is 1×10⁻⁶. 18 / cm 3 the following.

[0033]

[12] In the semiconductor device described in [1], the ohmic electrode contains one or two metallic elements selected from Groups 4 to 13 of the periodic table.

[0034]

[13] In the semiconductor device described in [1], the Schottky electrode contains one or two metallic elements selected from Groups 4 to 13 of the periodic table.

[0035]

[14] In the semiconductor device described in [1], the semiconductor device is a power device.

[0036]

[15] In the semiconductor device described in [1], the semiconductor device is a Schottky barrier diode (SBD).

[0037]

[16] An electronic device comprising a semiconductor device, characterized in that the semiconductor device is the semiconductor device described in [1].

[0038]

[17] A system comprising an electronic device, wherein the electronic device is the electronic device described in

[16] .

[0039] -Invention Effects-

[0040] The semiconductor device of the present invention is a GeO2 semiconductor device, which has excellent electrical characteristics. Attached Figure Description

[0041] Figure 1 This is an example of a schematic structural diagram of a film-forming apparatus suitable for use in this invention.

[0042] Figure 2 This is a schematic diagram illustrating an atomizing device suitably used in the present invention.

[0043] Figure 3 This is 1.n, which illustrates Example 1. + A graph showing the 2θ / ω result in the XRD diffraction results of the formation of the semiconductor layer.

[0044] Figure 4 This is a graph showing the results of the ω scan in the rocking curve determination of XRD diffraction in Example 1.

[0045] Figure 5 This is a schematic cross-sectional view illustrating a suitable example of the Schottky barrier diode (SBD) of the present invention.

[0046] Figure 6 This is a diagram schematically illustrating a suitable example of the Schottky barrier diode (SBD) of the present invention.

[0047] Figure 7 This is a schematic cross-sectional view of a suitable example of a Schottky barrier diode (SBD) in Example 1, and a surface image of a sample in Example 1 in which electrodes are formed on a crystal film.

[0048] Figure 8 This is a diagram showing a surface image of a sample in Example 1 where an electrode is formed on a crystal film.

[0049] Figure 9 This is a schematic cross-sectional view of an atomizing device suitably used in this invention, viewed from the side.

[0050] Figure 10 This is a graph showing the results of IV measurements in Example 1, with the vertical axis representing current (A) and the horizontal axis representing voltage (V).

[0051] Figure 11 This is a table showing the relationship between carrier concentration and depth derived from the CV measurement results in Example 1, with the vertical axis representing carrier concentration and the horizontal axis representing depth.

[0052] Figure 12 This illustrates 2.n of Example 1. - A graph showing the 2θ / ω result in the XRD diffraction results of the formation of the semiconductor layer.

[0053] Figure 13This is a graph showing the results of IV measurements performed on the ohmic properties of the SBD with a pseudo-longitudinal structure obtained by Example 1.

[0054] Figure 14 This is a graph showing the results of TLM measurements for the SBD with a pseudo-longitudinal structure obtained through Example 1.

[0055] Figure 15 This is a graph showing the results of secondary ion mass spectrometry (SIMS) analysis of the SBD with a pseudo-longitudinal structure obtained by Example 1.

[0056] Figure 16 This is a diagram schematically illustrating a suitable example of the metal-semiconductor field-effect transistor (MESFE) of the present invention.

[0057] Figure 17 This is a diagram that schematically illustrates a suitable example of a power supply system.

[0058] Figure 18 This is a diagram that schematically illustrates a suitable example of a system device.

[0059] Figure 19 This is a suitable example of a schematic diagram showing the power supply circuit of a power supply device.

[0060] -Explanation of Figure Markers-

[0061] 19. Film Forming Device

[0062] 20 film samples

[0063] 21 Sample Stage

[0064] 22a Carrier Gas Source

[0065] 22b Dilution gas source

[0066] 23a Flow regulating valve

[0067] 23b Flow regulating valve

[0068] 24 Raw material partition

[0069] 24a Feed solution for atomization

[0070] 24b Ultrasonic transmission substrate

[0071] 24c Taiwan

[0072] 26. Ultrasonic transducer

[0073] 27 Film Forming Room

[0074] 28 Heaters

[0075] 30 Atomizing device

[0076] 31. Guiding the neighbor

[0077] 33. Dilution gas supply pipe

[0078] 34 Carrier gas supply pipe

[0079] 35 Ultrasonic transmission tank

[0080] 36 Ultrasonic Transmitter Fluid

[0081] 37 Film Forming Room

[0082] 101a n - Type semiconductor layer

[0083] 101b n + Type semiconductor layer

[0084] 102 p-type semiconductor layer

[0085] 103 Metal Layer

[0086] 104 Insulating Layer

[0087] 105a Schottky electrode

[0088] 105b ohmic electrode. Detailed Implementation

[0089] The semiconductor device of the present invention includes a stacked structure in which a second semiconductor layer having the same crystal structure as the first semiconductor layer is stacked directly or alternately on a first semiconductor layer containing a crystalline oxide comprising germanium or a mixture thereof as a main component. The semiconductor device is characterized by further comprising: a Schottky electrode, Schottky-bonded to the second semiconductor layer; and an ohmic electrode, ohmically bonded to the first semiconductor layer. In this specification, "film" can be replaced with "layer". A "stacked structure" refers to a structure containing one or more crystalline layers, but may also contain layers other than crystalline layers (e.g., amorphous layers). Furthermore, the crystalline phase is preferably a monocrystalline layer, but may also be a polycrystalline layer.

[0090] In this invention, the carrier density of the first semiconductor layer is preferably 5 × 10⁻⁶. 18 cm -3 The preferred value is 1×10. 19 cm -3 That's all. Furthermore, the carrier density of the second semiconductor layer is preferably 1×10⁻⁶. 18 cm -3 The following is more preferably 5×10 17 cm -3The following is an example. Based on this optimized range, semiconductor characteristics can be improved, and furthermore, better electrical characteristics can be obtained.

[0091] In this invention, the term "main component" refers to the presence of germanium in the crystalline oxide at a concentration of 50 at% or more in the composition of the crystalline oxide. In embodiments of this invention, the presence of germanium in the crystalline oxide is preferably 70 at% or more in the composition of the crystalline oxide, more preferably 90 at% or more. Furthermore, the crystalline oxide in this invention is not particularly limited as long as it does not impair the purpose of this invention, but it is more preferable to include germanium dioxide as a main component. According to this preferred range, the interface becomes better, resulting in superior electrical properties and semiconductor properties. Additionally, the metal oxide film may also contain metals other than germanium. Examples of such other metals include one or more metals selected from Group 14 metals (such as tin or silicon) or Group 4 metals (such as titanium, zirconium oxide, or hafnium) of the periodic table, excluding germanium. The atomic ratio of germanium in the metal oxide film is preferably 0.5 or more. Furthermore, the crystal structure of the metal oxide film is not particularly limited; it can be a tetragonal rutile crystal structure, a trigonal α-quartz crystal structure, an orthorhombic CaCl2 crystal structure, an α-PbO2 crystal structure, or a tetragonal pyrite crystal structure. However, in this invention, a tetragonal rutile crystal structure is preferred. Additionally, the semiconductor layer is not particularly limited as long as it does not impede the purpose of this invention; however, in this invention, a crystalline oxide with a rutile crystal structure is preferred as the constituent material. By setting it within this preferred range, a crystalline film with better semiconductor properties can be achieved.

[0092] Furthermore, the crystal structure of the crystalline oxide is not particularly limited; it can be a tetragonal rutile crystal structure, a trigonal α-quartz crystal structure, an orthorhombic CaCl2 crystal structure, an α-PbO2 crystal structure, or a tetragonal pyrite crystal structure. However, in this invention, a tetragonal rutile crystal structure is preferred. This preferred range allows for improved semiconductor properties.

[0093] The preferred layered structure described above is, for example, constructed by using... Figure 1 The film-forming apparatus shown allows for easier doping control. In this invention, the area of ​​the semiconductor layer is more preferably 100 mm². 2The area mentioned above. Furthermore, the semiconductor layer is preferably a single-crystal film. Based on these preferred ranges, the semiconductor layer can achieve better voltage withstand capability and superior electrical characteristics. Additionally, the film thickness of the semiconductor layer is not particularly limited as long as it does not hinder the purpose of the present invention; however, in the present invention, the semiconductor layer is preferably 500 nm or more, and the second semiconductor layer is preferably 1.0 μm or more. By setting such preferred film thickness or area, when the laminated structure is applied to a semiconductor device, the semiconductor device can be endowed with superior electrical characteristics such as voltage withstand capability.

[0094] The semiconductor layer in this invention preferably contains a dopant. The dopant is not particularly limited as long as it does not impede the purpose of this invention, but elements from Group 15 or Group 13 of the periodic table are listed as examples. In this invention, the dopant preferably contains elements from Group 15 of the periodic table. Examples of elements from Group 15 include nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). Examples of elements from Group 13 include boron (B), aluminum (Al), gallium (Ga), and indium (In). According to this preferred range, better electrical properties can be obtained, and it is also easier to manufacture.

[0095] Furthermore, the ohmic electrode is not particularly limited as long as it contains one or two metallic elements selected from Groups 4 to 13 of the periodic table; it can be a single-layer metal layer or contain two or more metal layers. The method of stacking the metal layers is not particularly limited; known methods such as vacuum evaporation and sputtering are examples. Additionally, the metal constituting the ohmic electrode can also be an alloy. Preferably, the ohmic electrode contains one or two metallic elements selected from Groups 4 to 13 of the periodic table. As one or more metallic elements belonging to any one of Groups 4 to 13 of the periodic table, list the metallic elements of Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 12, and Group 13 of the periodic table, as well as their alloys. Examples of metals belonging to any one of Groups 4 to 13 of the periodic table include metals from Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 12, and Group 13, as well as their alloys. Examples of metals belonging to Group 4 include titanium (Ti), zirconium (Zr), hafnium (Hf), and their alloys; however, titanium is preferably included in this invention. Examples of metals belonging to Group 5 include vanadium (V), niobium (Nb), tantalum (Ta), and their alloys. Examples of metals belonging to Group 6 include chromium (Cr), molybdenum (Mo), tungsten (W), and their alloys. Examples of metals belonging to Group 7 of the periodic table include manganese (Mn), technetium (Tc), rhenium (Re), and their alloys. Examples of metals belonging to Group 8 of the periodic table include iron (Fe), ruthenium (Ru), osmium (Os), and their alloys. Examples of metals belonging to Group 9 of the periodic table include cobalt (Co), rhodium (Rh), iridium (Ir), and their alloys. Examples of metals belonging to Group 10 of the periodic table include nickel (Ni), palladium (Pd), platinum (Pt), and their alloys. Examples of metals belonging to Group 11 of the periodic table include copper (Cu), silver (Ag), gold (Au), and their alloys, but in this invention, gold (Au) is preferably included.Examples of metals belonging to Group 12 of the periodic table include zinc (Zn), cadmium (Cd), and their alloys. Examples of metals belonging to Group 13 of the periodic table include aluminum (Al), gallium (Ga), indium (In), and their alloys. Furthermore, in this invention, the ohmic electrode preferably comprises Ti and / or Au, more preferably Ti and Au. Based on this preferred range, the semiconductor properties of the first semiconductor layer (e.g., durability, insulation breakdown voltage, withstand voltage, on-resistance, stability, etc.) can be improved, and the ohmic properties can also be improved.

[0096] The Schottky electrode is not particularly limited as long as it contains one or two metallic elements selected from Groups 4 to 13 of the periodic table. It can be a single metal layer or contain two or more metal layers. The method of stacking the metal layers is not particularly limited; known methods such as vacuum evaporation and sputtering are examples. Furthermore, the metal constituting the Schottky electrode can also be an alloy. Preferably, the Schottky electrode contains one or two metallic elements selected from Groups 4 to 13 of the periodic table. The following list includes one or more metallic elements belonging to any one of Groups 4 through 13 of the periodic table, as well as their alloys. Examples of metals belonging to Groups 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 of the periodic table are listed. Examples of metals belonging to Group 4 include titanium (Ti), zirconium (Zr), hafnium (Hf), and their alloys. Examples of metals belonging to Group 5 include vanadium (V), niobium (Nb), tantalum (Ta), and their alloys. Examples of metals belonging to Group 6 include chromium (Cr), molybdenum (Mo), tungsten (W), and their alloys. Examples of metals belonging to Group 7 of the periodic table include manganese (Mn), technetium (Tc), rhenium (Re), and their alloys. Examples of metals belonging to Group 8 of the periodic table include iron (Fe), ruthenium (Ru), osmium (Os), and their alloys. Examples of metals belonging to Group 9 of the periodic table include cobalt (Co), rhodium (Rh), iridium (Ir), and their alloys. Examples of metals belonging to Group 10 of the periodic table include nickel (Ni), palladium (Pd), platinum (Pt), and their alloys, but in this invention, Ni or Pt is preferably included. Examples of metals belonging to Group 11 of the periodic table include copper (Cu), silver (Ag), gold (Au), and their alloys. Examples of metals belonging to Group 12 of the periodic table include zinc (Zn), cadmium (Cd), and their alloys. Examples of metals belonging to Group 13 of the periodic table include aluminum (Al), gallium (Ga), indium (In), and their alloys. Furthermore, in this invention, the Schottky electrode preferably comprises Au and / or Ni, more preferably Au and Ni. Based on this preferred range, the semiconductor properties of the second semiconductor layer (e.g., durability, insulation breakdown voltage, withstand voltage, on-resistance, stability, etc.) can be improved, and the Schottky properties can also be improved.

[0097] In this invention, the first semiconductor layer can be deposited on the substrate in its original state, but alternatively, layers different from the first semiconductor layer (e.g., n-type semiconductor layer, n...) can be stacked on the substrate. + Type semiconductor layer, n - The first semiconductor layer is then deposited on another layer, such as a semiconductor layer (including a semi-insulator layer), a buffer layer, or an insulating layer (including a semi-insulator layer). In particular, a buffer layer can be suitably used to mitigate the lattice constant difference between the first semiconductor layer and the substrate. Examples of materials constituting the buffer layer include SnO2, TiO2, VO2, MnO2, RuO2, CsO2, IrO2, GeO2, CuO2, PbO2, AgO2, CrO2, SiO2, SiC, GaN, Pt, and mixtures thereof.

[0098] For example, by using Figure 1 The film-forming apparatus shown simplifies the preparation of a semiconductor layer comprising a crystalline oxide containing germanium or a mixture thereof as a main component. This semiconductor layer is readily obtainable. It is a known apparatus. Furthermore, the film-forming apparatus can be used for appropriate doping. The doped crystal is suitable for use as a semiconductor film or semiconductor layer, and existing doping methods for oxidizing semiconductors can be employed using n-type or p-type dopants. Examples of n-type dopants include antimony (Sb), arsenic (As), bismuth (Bi), phosphorus (P), fluorine (F), niobium (Nb), vanadium (V), tantalum (Ta), or tungsten (W). Examples of p-type dopants include aluminum (Al), gallium (Ga), or indium (In). In this invention, the resulting stacked structure is also included.

[0099] The laminated structure is maintained as is or after undergoing known processing methods such as substrate peeling, and is then used in a semiconductor device using known methods. The ohmic electrode and the Schottky electrode can be a single metal layer or comprise two or more metal films. The lamination method for the ohmic electrode and the Schottky electrode is not particularly limited; known methods such as vacuum evaporation, sputtering, and atomization CVD are examples. Examples of semiconductor devices include Schottky barrier diodes (SBDs). Furthermore, these semiconductor devices can be used in various applications, including modules equipped with them and electronic devices and components incorporating them, and are particularly preferred for power devices. The semiconductor device can be classified as a horizontal element (horizontal device) with electrodes formed on one side of the semiconductor layer, and a vertical element (vertical device) with electrodes on both sides of the semiconductor layer. In this invention, the semiconductor device can be suitably used in both horizontal and vertical devices.

[0100] Hereinafter, examples of semiconductor devices suitably used in the present invention will be described in more detail with the aid of accompanying drawings; however, the present invention is not limited to these examples. Furthermore, suitable examples of using a single-crystal film of the present invention as a semiconductor layer are shown below.

[0101] In the Figure 5 When a reverse bias is applied to the SBD, the depletion layer (not shown) extends into the n-type semiconductor layer 101a, thus becoming a high-voltage SBD. Conversely, when a forward bias is applied, electrons flow from the ohmic electrode 105b to the Schottky electrode 105a. Therefore, the SBD using this stacked structure exhibits excellent performance in high voltage / high current applications, good Schottky characteristics, fast switching speed, and excellent voltage withstand and reliability.

[0102] Figure 6 It shows that n has - Type semiconductor layer 101a, n + A suitable example of a Schottky barrier diode (SBD) comprising a p-type semiconductor layer 101b, a p-type semiconductor layer 102, a metal layer 103, an insulating layer 104, a Schottky electrode 105a, and an ohmic electrode 105b. Furthermore, the metal layer 103, for example, contains a metal such as Al and covers the Schottky electrode 105a.

[0103] Examples of materials used for the insulating layer 104 include GaO, AlGaO, InAlGaO, AlInZnGaO4, AlN, Hf2O3, SiN, SiON, Al2O3, MgO, GdO, SiO2, or Si3N4. However, in this invention, a material with a corundum structure is preferred. By using an insulator with a corundum structure as the insulating layer, the semiconductor characteristics at the interface can be well manifested. The insulating layer 104 is disposed in n - Between the semiconductor layer 101 and the Schottky electrode 105a. The insulating layer can be formed by known methods such as sputtering, vacuum evaporation, or CVD.

[0104] For other structures, etc., as described above Figure 5 The same applies to SBD.

[0105] Figure 6 SBD and Figure 5 Compared to SBD, it has even better insulation properties and higher current controllability.

[0106] (MESFET)

[0107] Figure 16 An example of a metal-semiconductor field-effect transistor (MESFET) used in this invention is shown. Figure 16The MESFET has: n - Type semiconductor layer 111a, n + The semiconductor layer 111b, buffer layer 118, semi-insulating layer 114, gate electrode 115a, source electrode 115b, and drain electrode 115c are included.

[0108] The gate electrode preferably has Schottky characteristics, and in this invention, the Schottky electrode can be suitably used as such a gate electrode. Additionally, the drain electrode preferably has ohmic characteristics, and the ohmic electrode can be suitably used as the drain electrode.

[0109] exist Figure 16 In MESFETs, due to the formation of a good depletion layer under the gate electrode, the current flowing from the drain electrode to the source electrode can be efficiently controlled.

[0110] (Semiconductor Systems)

[0111] The above-described semiconductor devices are used in semiconductor systems, such as systems using power supply devices. The power supply device can be fabricated using known methods to connect the semiconductor device with wiring patterns, etc. Figure 17 The image shows an example of a power supply system. Figure 17 In the example shown, multiple power supply devices and control circuits are used to construct the power supply system. For example... Figure 18 As shown, the power supply system can be used in a system device in combination with electronic circuitry. Furthermore, an example of a power supply circuit diagram of the power supply device is shown below. Figure 19 . Figure 19 The diagram illustrates a power supply circuit for a power supply device consisting of a power circuit and a control circuit. This circuit converts DC voltage to AC voltage at a high frequency using an inverter (composed of MOSFETs A-D). After insulation and voltage transformation via a transformer, the voltage is rectified by rectifier MOSFETs (A-B) and then smoothed by a DCL (smoothing coils L1 and L2) and a capacitor to output a DC voltage. A voltage comparator compares the output voltage with a reference voltage, and a PWM control circuit controls the inverter and rectifier MOSFETs to achieve the desired output voltage.

[0112] [Example]

[0113] (Example 1)

[0114] 1.n + Formation of semiconductor layer

[0115] 1-1. Film forming device

[0116] Figure 1This diagram illustrates an example of a suitable configuration of the film-forming apparatus of the present invention. The film-forming apparatus 19 comprises a sample to be film-formed 20, a sample stage 21, a carrier gas source 22a, a carrier gas source 22b, a flow regulating valve 23a, a flow regulating valve 23b, a film-forming chamber 27, a heater 28, and an atomizing device 30. The atomizing device 30 comprises a raw material partition 24, an atomizing raw material solution 24a, an ultrasonic transmission substrate 24b, a stage 24c, an ultrasonic transducer 26, a guide partition 31, an ultrasonic transmission liquid tank 35, and an ultrasonic transmission liquid 36. Furthermore, Figure 2 This diagram illustrates an example of another suitable mode of film-forming apparatus when the atomizing device of the present invention is used as an atomizing stage for film formation. The atomizing device 30 is configured to include a raw material partition 24, an atomizing raw material solution 24a, an ultrasonic transmission substrate 24b, a stage 24c, an ultrasonic transducer 26, a guide partition 31, an ultrasonic transmission liquid tank 35, and an ultrasonic transmission liquid 36. The sample stage 21 is made of quartz, and the surface on which the film-forming sample 20 is placed is inclined from a horizontal plane. By making both the film-forming chamber 27 and the sample stage 21 quartz, impurities originating from the device are suppressed from entering the crystalline film formed on the film-forming sample 20. The atomizing raw material solution 24a is contained within the raw material partition 24. The guide partition 31 is in contact with the ultrasonic transmission substrate 24b. Figure 9 This is a schematic cross-sectional view of the atomizing device used in this invention, viewed from the side. Figure 9 The atomizing device 30 includes a raw material partition 24, an ultrasonic transmission substrate 24b, a stage 24c, an ultrasonic transducer 26, a guide partition 31, and an ultrasonic transmission liquid tank 35. The guide partition 31 is connected to the ultrasonic transmission liquid tank 35. Here, the ultrasonic transducer is surrounded by the guide partition to the ultrasonic transmission substrate, and by using the guide partition 31, the ultrasonic waves emitted by the ultrasonic transducer 26 are transmitted to the raw material partition 24 more efficiently.

[0117] The ultrasonic transducer is a component capable of generating ultrasonic vibrations. It is not particularly limited as long as it can irradiate the bottom surface of the material partition wall with ultrasonic waves; any known ultrasonic transducer can be used. The frequency of the ultrasonic transducer is not particularly limited as long as it does not hinder the purpose of the present invention, but is preferably 2.4 MHz or higher, more preferably 3.0 MHz or higher. For example, an ultrasonic transducer configured as follows: electrodes are provided on both sides of a disc-shaped piezoelectric element, and an oscillator is connected to the electrodes. When the oscillation frequency is changed, ultrasonic waves with a resonant frequency in the thickness direction and a radial resonant frequency of the piezoelectric transducer are generated. Based on this preferred range, the particle size of the mist generated by atomization can be made smaller, and the atomization efficiency can be improved.

[0118] The raw material partition in this invention is not particularly limited as long as it can accommodate the atomizing raw material. Preferably, the raw material partition is bottomless, and the raw material partition and the ultrasonic transmission liquid tank are fitted or screwed together through an ultrasonic transmissive substrate. This seals the bottom surface of the raw material partition with the ultrasonic transmissive substrate, allowing the raw material partition to accommodate the atomizing raw material liquid. For example, when the ultrasonic transmissive substrate is a polymer film, the polymer film is clamped, and the bottom surface of the raw material partition is sealed by the ultrasonic transmissive substrate. This sealing allows the raw material partition to accommodate the atomizing raw material liquid. The fitting or screwing method between the raw material partition and the ultrasonic transmission liquid tank is not particularly limited as long as it does not impede the purpose of this invention, and can be any known method. Examples of fitting methods include: providing a recess, convex part, or concave-convex part in the raw material partition and providing a corresponding fitting part in the ultrasonic transmission liquid tank; or providing a recess, convex part, or concave-convex part in the ultrasonic transmission liquid tank and providing a corresponding fitting part in the raw material partition. Examples of engagement methods include: providing an external threaded portion in the raw material partition wall and an internal threaded portion in the ultrasonic transmission liquid tank; or providing an external threaded portion in the ultrasonic transmission liquid tank and an internal threaded portion in the raw material partition wall. In this invention, known components can also be used to fit and thread the raw material partition wall and the ultrasonic transmission liquid tank. Furthermore, since the ultrasonic transmissive substrate can be used more effectively, the raw material partition wall and the ultrasonic transmission liquid tank preferably have substantially the same cross-sectional shape and, more preferably, substantially the same cross-sectional area.

[0119] Furthermore, in this invention, it is preferable that the raw material partition is a covered cylindrical body with a lid. The shape of the lid is not particularly limited as long as it serves as a lid for the raw material partition, but it is preferred because a lid that can seal the space within the raw material partition improves atomization efficiency and mist control. Additionally, the material of the lid is not particularly limited; it can be the same material as the raw material partition or a different material. It can be a known material, an inorganic material, or an organic material. In this invention, the material of the lid preferably includes glass, quartz, or a fluorinated resin as a main component, and more preferably, a fluorinated resin as a main component. Examples of fluorinated resins include polytetrafluoroethylene (PTFE), modified PTFE, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, or ethylene-tetrafluoroethylene copolymer.

[0120] In this invention, as described above, it is preferable that the raw material partition is a covered cylindrical body. If the raw material partition has a cover, it can be sealed, and the atomizing raw material can be replenished using spatial pressure. More specifically, when the liquid level of the atomizing raw material decreases due to atomization, the spatial pressure of the raw material partition increases, causing the liquid level to reach the front end of the piping. The space within the raw material partition and the space within the replenishment container containing the replenished atomizing raw material are connected via the piping. Gas in the space within the raw material partition can be drawn into the space within the replenishment container via the piping, and the atomizing raw material in the replenishment container can be replenished into the raw material partition. Having such a replenishment means is also one of the preferred embodiments of this invention.

[0121] The atomizing raw material is not particularly limited as long as it can be atomized; it can be a known atomizing raw material liquid, or a liquid dispersion medium such as a sol. It can be a raw material liquid containing organic compounds or inorganic compounds. In this invention, the atomizing raw material liquid is preferably a film-forming raw material liquid, and more preferably a raw material liquid containing metals. Examples of metals include, for instance, one or more selected from gold (Au), silver (Ag), platinum (Pt), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), palladium (Pd), cobalt (Co), rhodium (Rh), ruthenium (Ru), chromium (Cr), molybdenum (Mo), germanium (Ge), titanium (Ti), tin (Sn), zirconium (Zr), vanadium (V), yttrium (Y), zinc (Zn), magnesium (Mg), scandium (Sc), hafnium (Hf), antimony (Sb), bismuth (Bi), tantalum (Ta), iridium (Ir), tungsten (W), niobium (Nb), lanthanum (La), cerium (Ce), and aluminum (Al). Suitable examples include one or more selected from gallium, germanium, titanium, tin, niobium, vanadium, antimony, bismuth, tantalum, aluminum, and indium. In this invention, because it can achieve excellent film-forming effects, the atomization feed solution is preferably a film-forming feed solution, and more preferably a feed solution for atomized CVD. Furthermore, the atomizing feed liquid can be of one type or two or more types. For example, when using two or more types of feed liquid, at least one type can be a feed liquid containing inorganic compounds, and the other types can be feed liquids containing organic compounds.

[0122] The ultrasonic transmission liquid tank in this invention is not particularly limited as long as it can contain the ultrasonic transmission liquid. Furthermore, the shape of the ultrasonic transmission liquid tank is not particularly limited, but in this invention, a cylindrical, substantially cylindrical, polygonal cylindrical, or substantially polygonal cylindrical shape is preferred, more preferably cylindrical or substantially cylindrical, and most preferably cylindrical. The constituent material of the ultrasonic transmission liquid tank is not particularly limited; it can be inorganic or organic. However, in this invention, the constituent material preferably includes glass, quartz, or fluorinated resin as the main component, more preferably fluorinated resin as the main component. The ultrasonic transmission liquid is not particularly limited as long as it is a liquid capable of transmitting ultrasonic waves, and also includes liquid dispersion media such as sols. Examples of ultrasonic transmission liquids include inorganic solvents and organic solvents, but in this invention, an inorganic solvent is preferred, more preferably water. The water mentioned includes, for example, pure water, ultrapure water, tap water, well water, mineral water, water containing minerals, hot spring water, spring water, fresh water, and seawater. Examples of such water include water that has undergone purification, heating, sterilization, filtration, ion exchange, electrolysis, osmotic pressure adjustment, buffering, etc. (e.g., ozone water, purified water, hot water, ion-exchanged water, physiological saline, phosphate buffer, phosphate-buffered saline, etc.). Furthermore, in this invention, it is preferable to make the interior of the ultrasonic transmission liquid tank a sealed state. By forming a sealed space, the atomization efficiency and mist controllability can be improved.

[0123] The ultrasonic transmissive substrate is not particularly limited as long as it does not impede the purpose of the present invention, and can be any known ultrasonic transmissive substrate. Examples of ultrasonic transmissive substrates include polymer films. Examples of constituent materials of the ultrasonic transmissive substrate include thermoplastic resins and thermosetting resins, but in the present invention, thermoplastic resins are preferred. Examples of thermoplastic resins include polyolefins and fluorinated resins, with fluorinated resins being preferred as a main component. Examples of polyolefins include polyethylene and polypropylene. Examples of fluorinated resins include polytetrafluoroethylene, modified polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, or ethylene-tetrafluoroethylene copolymers. In the present invention, the fluorinated resin is preferably at least one selected from polytetrafluoroethylene, modified polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, and ethylene-tetrafluoroethylene copolymers. Based on this preferred range, the atomizing material can be transmitted more efficiently by ultrasound, resulting in a greater atomization volume.

[0124] The material of the guide partition is not particularly limited as long as it does not impede the purpose of the present invention, and examples include metals and polymers. Examples of polymers include natural resins, thermoplastic resins, and thermosetting resins. Alternatively, the guide partition may be coated with a metal. Examples of metals include Al, Cu, Ag, Ti, W, Mo, Fe, Ni, Cr, Zn, Sn, Rh, Pt, and Au. According to this preferred range, the transmission of ultrasonic vibrations can be more efficient and effective. The shape of the guide partition is not particularly limited as long as it does not impede the purpose of the present invention, but according to this embodiment, a cylindrical, substantially cylindrical, polygonal cylindrical, or substantially polygonal cylindrical shape is preferred. Furthermore, a frustum-shaped shape is also preferred, more preferably a frustum-shaped or substantially cylindrical shape, and most preferably a frustum-shaped shape. Additionally, the guide partition is not impeded as long as it does not impede the purpose of the present invention, and preferably it is through-hole. According to this preferred range, ultrasonic waves irradiated by the ultrasonic transducer can be transmitted to the ultrasonic transmission substrate more efficiently and effectively. The guide partition is not particularly limited as long as it does not impede the purpose of the present invention; it can be configured to be detachable or disposed on the ultrasonic radiating surface. However, in the present invention, it is preferred to be detachable. According to this preferred configuration, the atomizing device of the present invention can be cleaned more easily.

[0125] 1-2. Preparation of raw material solution for atomization

[0126] When preparing the atomization feed solution, the concentration of carboxyethyl germanium sesquioxide in the atomization feed solution is adjusted to 0.02 M. During adjustment, hydrochloric acid is present at a volume ratio of 10% in the atomization feed solution. Additionally, antimony chloride, used as an n-type dopant, is prepared to a concentration of 3 mol relative to the concentration of carboxyethyl germanium sesquioxide in the atomization feed solution.

[0127] 1-3. Film Preparation

[0128] Next, the atomizing feedstock solution 24a obtained through the preparation of the atomizing feedstock solution described in sections 1-2 above is contained in the feedstock partition 24. As the film-forming sample 20, a TiO2 (001) substrate with a rutile crystal structure containing a GeO2 crystal film is placed on the sample stage 21. This GeO2 crystal film is a square with one side of 17 mm and an average thickness of 500 μm, and has a rutile crystal structure. The heater 28 is activated, raising the temperature inside the film-forming chamber 27 to 700°C. Next, the flow regulating valve 23 is opened, supplying carrier gas from the carrier gas source 22a into the film-forming chamber 27. After the atmosphere in the film-forming chamber 27 is fully replaced with carrier gas, the flow rate of the carrier gas is adjusted to 1 L / min. Nitrogen gas is used as the carrier gas. In addition, the TiO2 (001) substrate with the rutile crystal structure of the GeO2 crystal film with the rutile crystal structure described above does not use antimony chloride as an n-type dopant. Otherwise, similarly as described above, it is obtained by forming a GeO2 crystal film with the rutile crystal structure described above on a TiO2 (001) substrate with the rutile crystal structure described above.

[0129] 1-4. Formation of oxide semiconductor crystal films

[0130] Next, the ultrasonic transducer 26 is vibrated at 3.0 MHz, and this vibration is propagated through the ultrasonic transmitter 25a to the atomizing feed solution 24a, thereby atomizing the feed solution 24a into feed particles. These feed particles are introduced into the film-forming chamber 27 by a carrier gas, where a reaction occurs. Through a CVD reaction on the film-forming surface of the sample 20, a tetragonal GeO2 crystalline film is formed on the sample 20. The film thickness is 500 nm.

[0131] 1-5. Evaluation

[0132] The GeO2 crystal film obtained by forming oxide semiconductor crystal films as described in sections 1-4 was measured using an X-ray diffraction apparatus. Figure 3 This is a graph showing the 2θ / ω result in the XRD diffraction results. According to... Figure 3 It is clear that the obtained crystalline film is a single-crystal GeO2 film with a tetragonal (002) orientation and a rutile structure. Furthermore, the results of the ω-scan in the X-ray diffraction measurement are shown below. Figure 4 .according to Figure 4 The half-width of the rocking curve in the 002 diffraction peak of r-GeO2 is 350 arcsec. Based on this result, a GeO2 crystal film with good crystallinity is formed on a TiO2(001) substrate with a rutile crystal structure as n + Semiconductor layer.

[0133] Furthermore, the Hall effect was measured using the van der Pauw method to evaluate the electrical properties of the obtained film. The applied magnetic field frequency was set to 50 mHz at room temperature. The resulting carrier density was 9.28 × 10⁻⁶. 19 (1 / cm) 3 The mobility is 24 (cm). 2 ( / V·s). Additionally, the sheet resistance is 4.6 × 10⁻⁶. 1 (Ω / □). Resistivity is 2.76 × 10⁻⁶. -3 Ωcm. Furthermore, the carrier type is "n". Based on this result, the obtained GeO2 crystal film is considered as n. + Semiconductor layers have good electrical properties.

[0134] 2.n - Formation of semiconductor layer

[0135] Antimony chloride is not added to the atomization feed solution. Regarding the substrate, it uses materials that pass through the aforementioned 1.n... + The formation of the n-type semiconductor layer + The TiO2 (001) substrate with a GeO2 crystal film, except for the 1.n... + The formation of a semiconductor layer is similar to the formation of a semiconductor layer.

[0136] 2-1. Evaluation

[0137] The formed semiconductor layer was measured using an X-ray diffraction apparatus. Figure 12 The result for 2θ / ω in the XRD diffraction results is shown below. According to... Figure 12 It is clear that the obtained crystal film is a single-crystal GeO2 film with a tetragonal (002) orientation and a rutile structure. A GeO2 crystal film with good crystallinity is formed on a TiO2 (001) substrate with a rutile crystal structure. Furthermore, the obtained n... - The thickness of the semiconductor layer is 1.00 μm.

[0138] 3. Electrode Formation

[0139] Using photolithography and dry etching, a material with... Figure 7 The pseudo-vertical structure of the SBD is shown. Furthermore, the electrodes are formed by EB evaporation. The electrode formation conditions are shown below. Additionally, Figure 8 This is a diagram showing a surface image of a sample on which electrodes are formed on a crystal film.

[0140] (Conditions for the formation of ohmic electrodes)

[0141] Photolithography

[0142] HMDS 5000rpm 20s

[0143] LOR5A 5000rpm 60s, 180oC 5min

[0144] AZ5214E ​​5000rpm 60s, 110oC 1min

[0145] DWL 66+ 10mm, Int 50%, Filter 100%

[0146] TMAH 2.38wt%, 2min

[0147] rinse

[0148] Slag removal UV ozone 2min

[0149] EB deposition

[0150] Ti 75nm, 0.2nm / s

[0151] Au 75nm, 0.2nm / s

[0152] Stripping with NMP at 80°C for 30 minutes, followed by IPA, IPA, and rinsing.

[0153] RTA N2 0.5slm, 550oC, 60s

[0154] (Conditions for the formation of Schottky electrodes)

[0155] Photolithography

[0156] HMDS 5000rpm 20s

[0157] LOR5A 5000rpm 60s, 180oC 5min

[0158] AZ5214E ​​5000rpm 60s, 110oC 1min

[0159] DWL 66+ 10mm, Int 50%, Filter 100%

[0160] TMAH 2.38wt%, 2min

[0161] rinse

[0162] UV ozone ashing, 2 minutes

[0163] EB deposition

[0164] Ni 100nm, 0.2nm / s

[0165] Au 50nm, 0.2nm / s

[0166] Stripping with NMP at 80°C for 30 minutes, followed by IPA, IPA, and rinsing.

[0167] IV measurements were performed on the SBD with the pseudo-longitudinal structure obtained above. Figure 10 The results are shown in the image. According to... Figure 10 The Schottky characteristics were confirmed to be excellent. Based on these results, it can be concluded that Example 1 exhibits superior semiconductor and Schottky characteristics.

[0168] Furthermore, the ohmic properties of the obtained SBD with a pseudo-longitudinal structure were measured using IV. Figure 13 The results are shown in the image. According to... Figure 13 This confirms the formation of an ohmic contact. Furthermore, TLM measurements were performed on the obtained SBD with its pseudo-longitudinal structure, yielding a contact resistance of 6.6 × 10⁻⁶. -5 Ωcm 2 .exist Figure 14 The results of TLM measurements are shown. Based on these results, it is evident that the contact resistance is significantly improved. Therefore, the contact resistance of the product of this invention is 10 × 10⁻⁶. -5 Ωcm 2 The electrical characteristics are excellent.

[0169] Furthermore, regarding the n of the obtained SBD with pseudo-vertical structure - A semiconductor layer was used, and CV measurements were performed to calculate the carrier concentration based on the results. In Example 1, the carrier concentration was 1 × 10⁻⁶. -16 ~3×10 -17 cm -3 Within a certain range. Therefore, it can be seen that the carrier concentration can be easily controlled in this invention. Furthermore, the relationship between carrier concentration and depth calculated from the CV measurement results of Example 1 is shown below. Figure 11 .

[0170] Furthermore, the concentration of impurities contained in the r-GeO2 thin film was analyzed using secondary ion mass spectrometry (SIMS) to determine the pseudo-vertical structure of the obtained SBD. Figure 15 The results are shown in the image. According to... Figure 15 It can be seen that in n - The r-GeO2 thin film contains 2.6 × 10⁻⁶ elements. 15 atoms / cm 3 Sb on the left and right. And it can be known that in n... + The r-GeO2 thin film contains 5.76 × 10⁻⁶ 18 atoms / cm 3 The left and right Sb. Therefore, in this invention, in n- Layer, containing 2.6 × 10 15 atoms / cm 3 Sb on the left and right, in n + The r-GeO2 thin film contains 1×10 15 atoms / cm 3 Sb on the left and right.

[0171] Industrial availability

[0172] The semiconductor devices, electronic devices, and systems of the present invention are suitable for use, for example, in power devices.

Claims

1. A semiconductor device comprising a stacked structure, wherein a second semiconductor layer having the same crystal structure as the first semiconductor layer is stacked directly or through other layers on a first semiconductor layer containing a crystalline oxide comprising germanium or a mixture thereof as a main component. The semiconductor device is characterized in that... The semiconductor device further includes: Schottky electrode, which is Schottky bonded to the second semiconductor layer; and An ohmic electrode is ohmically bonded to the first semiconductor layer.

2. The semiconductor device according to claim 1, wherein, The second semiconductor layer contains a crystalline oxide comprising germanium or a mixture thereof as a main component.

3. The semiconductor device according to claim 1, wherein, The first semiconductor layer has a rutile structure.

4. The semiconductor device according to claim 1, wherein, The first semiconductor layer contains dopants.

5. The semiconductor device according to claim 4, wherein, The dopant contains elements from group 15 of the periodic table.

6. The semiconductor device according to claim 1, wherein, The crystalline oxide contains germanium dioxide as its main component.

7. The semiconductor device according to claim 1, wherein, The thickness of the first semiconductor layer is 500 nm or more.

8. The semiconductor device according to claim 1, wherein, The thickness of the second semiconductor layer is 1.0 μm or more.

9. The semiconductor device according to claim 1, wherein, The area of ​​the first semiconductor layer is 100 mm. 2 above.

10. The semiconductor device according to claim 1, wherein, The carrier concentration of the first semiconductor layer is 1×10 19 / cm 3 above.

11. The semiconductor device according to claim 1, wherein, The carrier concentration of the second semiconductor layer is 1×10 18 / cm 3 the following.

12. The semiconductor device according to claim 1, wherein, The ohmic electrode contains one or two metallic elements selected from groups 4 to 13 of the periodic table.

13. The semiconductor device according to claim 1, wherein, The Schottky electrode contains one or two metallic elements selected from groups 4 to 13 of the periodic table.

14. The semiconductor device according to claim 1, wherein, The semiconductor device is a power device.

15. The semiconductor device according to claim 1, wherein, The semiconductor device is a Schottky barrier diode, or SBD.

16. An electronic device comprising a semiconductor device, The electronic device is characterized in that, The semiconductor device is the semiconductor device according to claim 1.

17. A system comprising electronic equipment, characterized in that, The electronic device is the electronic device according to claim 16.

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