WO2009119479A1 - 半導体装置及びその製造方法 - Google Patents
半導体装置及びその製造方法 Download PDFInfo
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- WO2009119479A1 WO2009119479A1 PCT/JP2009/055611 JP2009055611W WO2009119479A1 WO 2009119479 A1 WO2009119479 A1 WO 2009119479A1 JP 2009055611 W JP2009055611 W JP 2009055611W WO 2009119479 A1 WO2009119479 A1 WO 2009119479A1
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 86
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 238000000034 method Methods 0.000 title claims description 9
- 239000000758 substrate Substances 0.000 claims abstract description 54
- 239000000203 mixture Substances 0.000 claims description 39
- 230000010287 polarization Effects 0.000 claims description 24
- 239000012535 impurity Substances 0.000 claims description 12
- 230000015556 catabolic process Effects 0.000 description 9
- 238000009826 distribution Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 239000002184 metal Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 3
- 238000000137 annealing Methods 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 238000005468 ion implantation Methods 0.000 description 3
- 238000001451 molecular beam epitaxy Methods 0.000 description 3
- 150000004767 nitrides Chemical class 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 230000005669 field effect Effects 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- -1 nitride compound Chemical class 0.000 description 1
- 238000001894 space-charge-limited current method Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/7801—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
- H01L29/7802—Vertical DMOS transistors, i.e. VDMOS transistors
- H01L29/7813—Vertical DMOS transistors, i.e. VDMOS transistors with trench gate electrode, e.g. UMOS transistors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/20—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only AIIIBV compounds
- H01L29/201—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only AIIIBV compounds including two or more compounds, e.g. alloys
- H01L29/205—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only AIIIBV compounds including two or more compounds, e.g. alloys in different semiconductor regions, e.g. heterojunctions
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66674—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
- H01L29/66712—Vertical DMOS transistors, i.e. VDMOS transistors
- H01L29/66734—Vertical DMOS transistors, i.e. VDMOS transistors with a step of recessing the gate electrode, e.g. to form a trench gate electrode
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/20—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only AIIIBV compounds
- H01L29/2003—Nitride compounds
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/20—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only AIIIBV compounds
- H01L29/201—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only AIIIBV compounds including two or more compounds, e.g. alloys
Definitions
- the present invention relates to a semiconductor device and a method of manufacturing the same.
- FIG. 8 schematically shows the semiconductor structure of a vertical GaN field effect transistor (hereinafter referred to as a vertical GaN FET).
- the vertical GaN FET shown in FIG. 8 is disclosed, for example, in Non-Patent Document 1.
- the vertical GaN FET shown in FIG. 8 has an n-type GaN layer (102) on a high concentration n-type GaN layer (101) and a p-type GaN layer (103) on it, and an n-type GaN layer on it.
- a GaN layer (104) on which there is an ohmic contact source electrode (111).
- a drain electrode (113) in ohmic contact on the heavily doped n-type GaN layer (101) exposed by removing the semiconductor layer.
- a gate electrode (112) in contact with the exposed side surface of the n-type GaN layer (104) and the p-type GaN layer (103) via the gate insulating film (121).
- the vertical GaN FET shown in FIG. 8 changes the concentration of electrons stored at the interface between the p-type GaN layer (103) and the gate insulating film (121) using a voltage applied to the gate electrode (112). Then, the current flowing between the source electrode (111) and the drain electrode (113) is controlled to perform the vertical FET operation.
- FIG. 9 is a band energy distribution diagram of the vertical GaN FET shown in FIG.
- the line between AB shown in FIG. 9 corresponds to the line between AB shown in FIG.
- Vds shown in FIG. 9 indicates a drain voltage.
- the thickness of the p-type GaN layer (103) is represented by Lch, and the impurity concentration is represented by Na.
- the thickness of the n-type GaN layer (102) is represented by Ldr
- the impurity concentration is represented by Nd.
- the spread (depletion layer width) of the depletion layer from the pn junction surface of these semiconductor layers is denoted as x p and x n , respectively. Since the charges in the depletion layers of the p-type GaN layer (103) and the n-type GaN layer (102) are equal, the following equation (1) holds.
- Breakdown voltage of the vertical GaN FET shown in FIG. 8; V B is designed with the thickness of the n-type GaN layer (102). That is, assuming that the breakdown electric field of GaN is Ecrit, the following formula (2) is obtained under the condition that the n-type GaN layer (102) is completely depleted.
- V B Ecrit ⁇ Ldr equation (2)
- R ON of the vertical GaN FET shown in FIG. 8 can be approximately expressed by the following equation (3).
- Patent Document 2 a document disclosed about a technique for realizing a low-resistance buffer layer in an electronic device (element for power electronics) operated by passing current to the SiC substrate and each nitride semiconductor layer (for example, Patent Document 2) reference).
- Patent Document 3 there is a document disclosed about a nitride semiconductor having a small resistance of an element and a high operating voltage (for example, see Patent Document 3).
- Patent Documents 1 to 4 disclose the technology relating to a semiconductor device formed of a nitride semiconductor layer, the description on suppressing the occurrence of the above-mentioned punch-through phenomenon and the necessity thereof are also disclosed. Not suggested.
- the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a semiconductor device capable of suppressing the occurrence of the punch-through phenomenon, which is the problem described above, and a method of manufacturing the same. .
- the present invention has the following features.
- the semiconductor device is There is a first n-type conductive layer on the substrate, a p-type conductive layer on it, a second n-type conductive layer on it, and the first n-type conductive layer on the lower surface of the substrate
- the semiconductor device is There is a first n-type conductive layer on the substrate, a p-type conductive layer on it, a second n-type conductive layer on it, and the first n-type conductive layer on the lower surface of the substrate
- a method of manufacturing a semiconductor device is Forming a first n-type conductive layer, a p-type conductive layer, and a second n-type conductive layer on the substrate;
- a drain electrode is formed on the lower surface of the substrate to be connected to the first n-type conductive layer,
- a source electrode is formed on the upper surface of the substrate to be in ohmic contact with the second n-type conductive layer,
- a gate electrode is connected to the first n-type conductive layer, the p-type conductive layer, and the second n-type conductive layer through an insulating film, and the gate electrode and the source electrode are alternately arranged.
- the p-type conductive layer is characterized by containing In.
- a method of manufacturing a semiconductor device is Forming a first n-type conductive layer, a p-type conductive layer, and a second n-type conductive layer on the substrate;
- a drain electrode is formed on the lower surface of the substrate to be connected to the first n-type conductive layer,
- a source electrode is formed on the upper surface of the substrate to be in ohmic contact with the second n-type conductive layer,
- a gate electrode is connected to the first n-type conductive layer, the p-type conductive layer, and the second n-type conductive layer through an insulating film, and the gate electrode and the source electrode are alternately arranged.
- the p-type conductive layer is configured to have a positive polarization charge on the side of the first n-type conductive layer and a negative polarization charge on the side of the second n-type conductive layer.
- the semiconductor device in the present embodiment has a first n-type conductive layer (2 ′) on a substrate (1 ′), a p-type conductive layer (3 ′) on it, and a second n-type conductive layer on it. And a drain electrode (13 ′) connected to the first n-type conductive layer (2 ′) on the lower surface of the substrate (1 ′).
- a gate electrode (12 ') in contact with the layer (4') through the insulating film (21 ') is alternately arranged
- the conductive layer (3 ') is characterized by including In.
- the semiconductor device in the present embodiment includes the first n-type conductive layer (2 ′) on the substrate (1 ′), and the p-type conductive layer (3 ′) on the first n-type conductive layer (2 ′).
- the drain electrode (13 ') connected to the first n-type conductive layer (2') on the lower surface of the substrate (1 ') and on the upper surface of the substrate (1')
- the gate electrode (12 ') in contact with the first conductive layer (4') through the insulating film (21 '), and the gate electrode (12') and the source electrode (11 ') are alternately arranged,
- the p-type conductive layer (3 ′) is characterized in that a positive polarization charge exists on the first n-
- the band energy is raised by the polarization charge of the p-type conductive layer (3 ′), the spread of the depletion layer due to the application of the drain voltage is suppressed, and the occurrence of the punch through phenomenon is suppressed. It becomes possible.
- the semiconductor device of the present embodiment will be described in detail with reference to the attached drawings.
- FIG. 2 schematically shows the semiconductor structure of the vertical GaN FET to be the semiconductor device of this embodiment.
- an n-type GaN layer (2), a p-type InGaN layer (3), and an n-type GaN layer (4) are sequentially formed on an n-type substrate (1) of Si or the like. There is. Below the n-type substrate (1) is a drain electrode (13) in ohmic contact. There is also an ohmic contact source electrode (11) on the n-type GaN layer (4). In addition, there is a gate electrode (12) in contact with the n-type GaN layer (4), the p-type InGaN layer (3), and the n-type GaN layer (2) through the gate insulating film (21). In the vertical GaN FET of this embodiment, the gate electrodes (12) and the source electrodes (11) are alternately arranged in a plane.
- FIG. 3 is a band energy distribution diagram of the vertical GaN FET of this embodiment.
- the line between A and B shown in FIG. 3 corresponds to the line between A and B shown in FIG. Further, Vds shown in FIG. 3 indicates a drain voltage.
- the vertical GaN FET according to the present embodiment by forming the p-type InGaN layer (3) on the n-type GaN layer (2), the positive (+), Negative (-) polarization charge is generated at the upper interface. Assuming that this polarization charge density is Np, the thickness Lch of the p-type InGaN layer (3) in consideration of the punch-through suppression is expressed by the following equation (5).
- Nd represents the impurity concentration of the n-type GaN layer (2).
- Na represents the impurity concentration of the p-type InGaN layer (3).
- x n represents the depletion layer width of the n-type GaN layer (2).
- band energy is raised by polarization charges generated in the p-type InGaN layer (3), and the spread of the depletion layer due to the application of the drain voltage can be suppressed. Therefore, thinning of the p-type InGaN layer (3) can be realized while suppressing the occurrence of the punch-through phenomenon.
- the vertical GaN FET of this embodiment can make the p-type InGaN layer (3) thinner than the semiconductor device shown in FIG. 8 related to the present invention, and can realize the reduction of on-resistance. . Further, in the vertical GaN FET according to the present embodiment, since the p-type InGaN layer (3) with In added is used as the p-type layer, high concentration is possible, and the occurrence of punch-through phenomenon is suppressed. The p-type InGaN layer (3) can be thinned to realize on-resistance reduction.
- a semiconductor layer is formed on an n-type substrate (1) made of conductive Si by, for example, a molecular beam epitaxy (MBE) growth method.
- the semiconductor layer formed by this method is, in order from the n-type substrate (1) side, an n-type GaN drift layer (2) (film thickness 1 mm, doping concentration 1 ⁇ 10 17 cm ⁇ 3 ), p-type In 0.2 Ga 0.8 N
- the channel layer 3 film thickness 0.1 mm, doping concentration 5 ⁇ 10 18 cm ⁇ 3
- the n-type GaN cap layer 4 film thickness 0.1 mm, doping concentration 5 ⁇ 10 17 cm ⁇ 3
- a metal such as Ti / Al is vapor deposited on the lower portion of the n-type substrate (1) and the upper portion of the n-type GaN layer (4) to form a source electrode (11) and a drain electrode (13). And make an ohmic contact by annealing at 650.degree.
- a part of the epitaxial layer structure (2, 3, 4) is removed by etching until the n-type GaN drift layer (2) is exposed, for example, after forming Al 2 O 3 as a gate insulating film (21)
- a metal such as Ni / Au is vapor deposited to form a gate electrode (12).
- the vertical GaN FET shown in FIG. 2 is manufactured.
- the above-described vertical GaN FET is an example, and the form of the ohmic electrode is not limited to the form described above, and any form is applicable.
- the source electrode (11) is formed on the top of the n-type GaN layer (4) in the above embodiment, the n-type conductivity is formed in part of the p-type InGaN layer (3) by ion implantation or the like. It is also possible to form the source electrode (11) in contact with both the n-type region and the p-type region.
- the drain electrode (13) is formed on the back surface of the n-type substrate (1), but the drain electrode (13) is formed to be connected to the n-type GaN layer (2) through a via hole or the like. Is also possible.
- the p-type InGaN layer (3) is positive on the n-type GaN layer (2) side and negative on the n-type GaN layer (4) side, as shown in FIGS. If it is possible to generate polarization charge in the p-type InGaN layer (3), the polarization charge of the n-type GaN layer (2, 4) and the p-type InGaN layer (3)
- the composition is not particularly limited, and any composition can be applied.
- each layer (2 to 4) constituting the vertical GaN FET described above is not limited to the embodiment described above, and for example, the n-type GaN layer (2) shown in FIG. 2 and FIG. x Ga 1-x N (where x is 0 ⁇ x ⁇ 1), and the p-type InGaN layer (3) is In y Ga 1-y N (where y is 0 ⁇ y ⁇ 1) It is also possible to construct the n-type GaN layer (4) so as to constitute Al z Ga 1-z N (where z is 0 ⁇ z ⁇ 1).
- the compositions of the n-type GaN layer (2) and the p-type InGaN layer (3) are different in composition, and positive (+) and upper side are formed at the lower interface of the p-type InGaN layer (3).
- band energy is raised by polarization charges generated in the p-type InGaN layer (3), making it possible to realize thinning of the p-type InGaN layer (3) in a state where the occurrence of punch through phenomenon is suppressed. .
- the second embodiment is characterized in that the n-type InGaN layer (5) and the p-type InGaN layer (3) have the same composition, as shown in FIG. As a result, it is possible to prevent a notch from being generated at the interface between the n-type InGaN layer (5) and the p-type InGaN layer (3).
- the second embodiment will be described in detail with reference to FIGS. 4 and 5.
- FIG. 4 schematically shows the semiconductor structure of the vertical GaN FET to be the semiconductor device of this embodiment.
- an n-type InGaN layer (5), a p-type InGaN layer (3), and an n-type GaN layer (4) are sequentially formed on an n-type substrate (1) such as Si.
- n-type substrate (1) such as Si.
- a drain electrode (13) in ohmic contact.
- ohmic contact source electrode (11) on the n-type GaN layer (4).
- gate electrode (12) in contact with the n-type GaN layer (4), the p-type InGaN layer (3), and the n-type InGaN layer (5) through the gate insulating film (21).
- the gate electrodes (12) and the source electrodes (11) are alternately arranged in a plane.
- FIG. 5 is a band energy distribution diagram of the vertical GaN FET of this embodiment.
- the composition of the n-type InGaN layer (5) and the p-type InGaN layer (3) is the same, so as in the first embodiment, the p-type InGaN layer The suppression effect of the punch through phenomenon by the polarization charge generated in 3) can not be obtained.
- the p-type InGaN layer (3) in which In is added is used for the p-type layer, high concentration can be achieved, and the p-type InGaN layer (3) can be thin while suppressing the occurrence of punch through phenomenon. To reduce on-resistance.
- a semiconductor layer is formed on an n-type substrate (1) made of conductive Si by, for example, a molecular beam epitaxy (MBE) growth method.
- the semiconductor layer formed by this method is, in order from the n-type substrate (1) side, an n-type In 0.2 GaN drift layer (5) (film thickness 1 mm, doping concentration 1 ⁇ 10 17 cm ⁇ 3 ), p-type In 0.2 Ga 0.8 N channel layer (3) (film thickness 0.1 mm, doping concentration 5 ⁇ 10 18 cm -3 ), n-type GaN cap layer (4) (film thickness 0.1 mm, doping concentration 5 ⁇ 10 17 cm -3 ) .
- MBE molecular beam epitaxy
- a metal such as Ti / Al is vapor deposited on the lower portion of the n-type substrate (1) and the upper portion of the n-type GaN layer (4) to form a source electrode (11) and a drain electrode (13). And make an ohmic contact by annealing at 650.degree.
- the vertical GaN FET shown in FIG. 4 is manufactured.
- the above-described vertical GaN FET is an example, and the form of the ohmic electrode is not limited to the form described above, and any form is applicable.
- the source electrode (11) is formed on the top of the n-type GaN layer (4) in the above embodiment, the n-type conductivity is formed in part of the p-type InGaN layer (3) by ion implantation or the like. It is also possible to form the source electrode (11) in contact with both the n-type region and the p-type region.
- the drain electrode (13) is formed on the back surface of the n-type substrate (1), but the drain electrode (13) is formed to be connected to the n-type InGaN layer (5) through a via hole or the like. Is also possible.
- each layer (3 to 5) constituting the above-described vertical GaN FET is not limited to the above-described embodiment, and, for example, the n-type InGaN layer (5) and p shown in FIGS.
- InGaN layer (3) is composed of In y Ga 1-y N (where y is 0 ⁇ y ⁇ 1), and n-type GaN layer (4) is Al z Ga 1-z N (where z is Can also be constructed to consist of 0 ⁇ z ⁇ 1).
- the n-type InGaN layer (5) and the p-type InGaN layer (3) have the same composition, and the n-type InGaN layer (5) and the p-type InGaN Notches were not generated at the interface with the layer (3).
- a composition modulation layer (6) in which the composition changes continuously or stepwise between the n-type Gan layer (2) and the p-type InGan layer (3).
- the polarization charge generated in the p-type InGaN layer (3) has the effect of suppressing the punch-through phenomenon, and the n-type GaN layer (2) and the p-type InGaN layer (3) It is possible not to generate a notch between them.
- the third embodiment will be described in detail with reference to FIGS. 6 and 7.
- FIG. 6 schematically shows the semiconductor structure of the vertical GaN FET to be the semiconductor device of the present embodiment.
- the vertical GaN FET according to the present embodiment includes the composition modulation layer (6) between the n-type GaN layer (2) and the p-type InGaN layer (3) constituting the vertical GaN FET according to the first embodiment. It is the inserted configuration.
- the composition modulation layer (6) is a layer whose composition changes continuously or stepwise.
- FIG. 6 shows a configuration in which the n-type composition modulation layer (6) is inserted.
- FIG. 7 is a band energy distribution diagram of the vertical GaN FET of this embodiment. Since the sum of positive polarization charges generated by the n-type composition modulation layer (6) and the p-type InGaN layer (3) is equal, polarization charges generated in the p-type InGaN layer (3) are the same as in the first embodiment. The effect of suppressing the punch-through phenomenon due to Furthermore, in the vertical GaN FET according to the present embodiment, since the n-type composition modulation layer (6) is inserted, there is no notch between the p-type InGaN layer (3) and the n-type GaN layer (2). A lower resistance can be realized than in the embodiment of.
- a semiconductor layer is formed on an n-type substrate (1) made of conductive Si by, for example, a molecular beam epitaxy (MBE) growth method.
- the semiconductor layer formed by this method is, in order from the n-type substrate (1) side, an n-type GaN drift layer (2) (film thickness 1 mm, doping concentration 1 ⁇ 10 17 cm ⁇ 3 ), n-type composition modulation layer (6 (Film thickness 50 nm, doping concentration 1 ⁇ 10 17 cm -3 ), p-type In 0.2 Ga 0.8 N channel layer (3) (film thickness 0.1 mm, doping concentration 5 ⁇ 10 18 cm -3 ), n-type GaN cap The layer (4) (film thickness 0.1 mm, doping concentration 5 ⁇ 10 17 cm ⁇ 3 ) is obtained.
- a metal such as Ti / Al is vapor deposited on the lower portion of the n-type substrate (1) and the upper portion of the n-type GaN layer (4) to form a source electrode (11) and a drain electrode (13). And make an ohmic contact by annealing at 650.degree.
- part of the epitaxial layer structure (2, 6, 3, 4) is removed by etching until the n-type GaN drift layer (2) is exposed, and, for example, Al 2 O 3 is formed as a gate insulating film (21) After that, a metal such as Ni / Au, for example, is deposited to form a gate electrode (12).
- a metal such as Ni / Au, for example, is deposited to form a gate electrode (12).
- the form of the ohmic electrode is not limited to the form described above, and any form is applicable.
- the source electrode (11) is formed on the top of the n-type GaN layer (4) in the above embodiment, the n-type conductivity is formed in part of the p-type InGaN layer (3) by ion implantation or the like. It is also possible to form the source electrode (11) in contact with both the n-type region and the p-type region.
- the drain electrode (13) is formed on the back surface of the n-type substrate (1), but the drain electrode (13) is formed to be connected to the n-type InGaN layer (5) through a via hole or the like. Is also possible.
- the composition modulation layer (6) has been described as n-type in the above embodiment, similar effects can be obtained with p-type.
- the semiconductor device of this embodiment has the following features.
- the semiconductor device of this embodiment has a first n-type conductive layer (2 or 5) on a substrate (1), a p-type conductive layer (3) on it, and a second n-type conductive layer thereon
- a conductive layer (4) the drain electrode (13) connected to the first n-type conductive layer (2 or 5) on the lower surface of the substrate (1), and the second n-type on the upper surface of the substrate (1)
- the gate electrode (12) and the source electrode (11) are alternately arranged
- the p-type conductive layer (3) contains In. It is characterized by comprising.
- the p-type conductive layer (3) is a positive and second n-type conductive layer on the first n-type conductive layer (2) side. (4) A negative polarization charge is present on the side. Further, the semiconductor device of the present embodiment is characterized in that the first n-type conductive layer (2) and the p-type conductive layer (3) have different compositions.
- the composition of the first n-type conductive layer (2) includes Al x Ga 1-x N (where x is 0 ⁇ x ⁇ 1), and p-type conductivity
- the composition of the layer (3) is characterized in that it contains In y Ga 1 -y N (where y is 0 ⁇ y ⁇ 1).
- the first n-type conductive layer (5) and the p-type conductive layer (3) have the same composition. It is characterized by In the semiconductor device of the present embodiment, the composition of the first n-type conductive layer (5) and the p-type conductive layer (3) is In y Ga 1 -y N (where y is 0). It is characterized by including ⁇ y ⁇ 1).
- the composition is continuous or stepwise between the first n-type conductive layer (2) and the p-type conductive layer (3). Characterized in that the composition modulation layer (6) is changed. Furthermore, in the semiconductor device of the present embodiment, the composition modulation layer (6) is characterized in that it is an n-type or p-type composition modulation layer.
- the thickness of the p-type conductive layer (3) is Lch
- the impurity concentration is Na
- the thickness of the first n-type conductive layer (2 or 5) is Ldr
- the impurity concentration is In the case of Nd, the condition of Lch> Ldr ⁇ Nd / Na is satisfied.
- the thickness of the p-type conductive layer (3) is Lch
- the impurity concentration is Na
- the thickness of the first n-type conductive layer (2) is Ldr
- the impurity concentration is Nd.
- the semiconductor device of the present embodiment described above it is possible to suppress the punch-through phenomenon and realize a vertical GaN FET with low on-resistance even in a low breakdown voltage region.
- the present invention is applicable to vertical GaN FETs.
- FIG. 2 is a diagram showing a band energy distribution of a semiconductor device related to the present invention.
- V B the on-resistance; vertical breakdown voltage of GaN FET is a diagram predicted by the R ON, the relationship calculation.
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Abstract
Description
特に、p型GaN層(103)の場合、高濃度化が困難(1017cm-3程度)であるため、p型GaN層(103)の空乏層幅;xpが大きくなり、p型GaN層(103)の薄層化によるオン抵抗低減に限界がある。
本発明にかかる半導体装置は、
基板上に第1のn型導電層があり、その上にp型導電層があり、その上に第2のn型導電層があり、前記基板下面には前記第1のn型導電層と接続したドレイン電極があり、前記基板上面には前記第2のn型導電層とオーム性接触するソース電極と、前記第1のn型導電層、前記p型導電層、前記第2のn型導電層に絶縁膜を介して接触するゲート電極があり、前記ゲート電極と前記ソース電極とが交互に配置されており、前記p型導電層は、Inを含んで構成することを特徴とする。
基板上に第1のn型導電層があり、その上にp型導電層があり、その上に第2のn型導電層があり、前記基板下面には前記第1のn型導電層と接続したドレイン電極があり、前記基板上面には前記第2のn型導電層とオーム性接触するソース電極と、前記第1のn型導電層、前記p型導電層、前記第2のn型導電層に絶縁膜を介して接触するゲート電極があり、前記ゲート電極と前記ソース電極とが交互に配置されており、前記p型導電層は、前記第1のn型導電層側に正、前記第2のn型導電層側に負の分極電荷が存在することを特徴とする。
本発明にかかる半導体装置の製造方法は、
基板上に第1のn型導電層、p型導電層、第2のn型導電層を形成し、
前記基板下面には、前記第1のn型導電層と接続するようにドレイン電極を形成し、
前記基板上面には、前記第2のn型導電層とオーム性接触するようにソース電極を形成し、
前記第1のn型導電層、前記p型導電層、前記第2のn型導電層に絶縁膜を介してゲート電極を接続し、前記ゲート電極と前記ソース電極とを交互に配置し、
前記p型導電層は、Inを含んで構成することを特徴とする。
基板上に第1のn型導電層、p型導電層、第2のn型導電層を形成し、
前記基板下面には、前記第1のn型導電層と接続するようにドレイン電極を形成し、
前記基板上面には、前記第2のn型導電層とオーム性接触するようにソース電極を形成し、
前記第1のn型導電層、前記p型導電層、前記第2のn型導電層に絶縁膜を介してゲート電極を接続し、前記ゲート電極と前記ソース電極とを交互に配置し、
前記p型導電層は、前記第1のn型導電層側に正、前記第2のn型導電層側に負の分極電荷が存在するように構成することを特徴とする。
まず、図1を参照しながら、本実施形態の半導体装置の概要について説明する。
<半導体装置の構成>
まず、図2を参照しながら、本実施形態の半導体装置の構成について説明する。なお、図2は、本実施形態の半導体装置となる縦型GaN FETの半導体構造を模式的に示したものである。
次に、本実施形態の半導体装置となる縦型GaN FETの製造方法について説明する。
次に、第2の実施形態について説明する。
まず、図4を参照しながら、本実施形態の半導体装置の構成について説明する。なお、図4は、本実施形態の半導体装置となる縦型GaN FETの半導体構造を模式的に示したものである。
次に、本実施形態の縦型GaN FETの製造方法について説明する。
次に、第3の実施形態について説明する。
まず、図6を参照しながら、本実施形態の半導体装置の構成について説明する。なお、図6は、本実施形態の半導体装置となる縦型GaN FETの半導体構造を模式的に示したものである。
次に、本実施形態の縦型GaN FETの製造方法について説明する。
以上の説明から明らかなように、本実施形態の半導体装置は、以下の特徴を有することになる。
2’ 第1のn型導電層
3’ p型導電層
4’ 第2のn型導電層
11’ ソース電極
12’ ゲート電極
13’ ドレイン電極
21’ 絶縁膜
1 n型基板
2 n型GaN層(n型GaNドリフト層)
3 p型InGaN層(p型InGaNチャネル層)
4 n型GaN層(n型GaNキャップ層)
5 n型InGaN層(n型InGaNドリフト層)
6 組成変調層
11 ソース電極
12 ゲート電極
13 ドレイン電極
21 ゲート絶縁膜
101 高濃度n型GaN層
102 n型GaN層
103 p型GaN層(p型GaNチャネル層)
104 n型GaN層(n型GaNキャップ層)
111 ソース電極
112 ゲート電極
113 ドレイン電極
121 ゲート絶縁膜
Claims (12)
- 基板上に第1のn型導電層があり、その上にp型導電層があり、その上に第2のn型導電層があり、前記基板下面には前記第1のn型導電層と接続したドレイン電極があり、前記基板上面には前記第2のn型導電層とオーム性接触するソース電極と、前記第1のn型導電層、前記p型導電層、前記第2のn型導電層に絶縁膜を介して接触するゲート電極があり、前記ゲート電極と前記ソース電極とが交互に配置されており、前記p型導電層は、Inを含んで構成することを特徴とする半導体装置。
- 基板上に第1のn型導電層があり、その上にp型導電層があり、その上に第2のn型導電層があり、前記基板下面には前記第1のn型導電層と接続したドレイン電極があり、前記基板上面には前記第2のn型導電層とオーム性接触するソース電極と、前記第1のn型導電層、前記p型導電層、前記第2のn型導電層に絶縁膜を介して接触するゲート電極があり、前記ゲート電極と前記ソース電極とが交互に配置されており、前記p型導電層は、前記第1のn型導電層側に正、前記第2のn型導電層側に負の分極電荷が存在することを特徴とする半導体装置。
- 前記第1のn型導電層と、前記p型導電層と、が異なる組成で構成されていることを特徴とする請求項1または請求項2記載の半導体装置。
- 前記第1のn型導電層の組成には、AlxGa1-xN(但し、xは、0≦x≦1)を含み、前記p型導電層の組成には、InyGa1-yN(但し、yは、0<y≦1)を含んでいることを特徴とする請求項1から請求項3の何れかの請求項に記載の半導体装置。
- 前記第1のn型導電層と、前記p型導電層と、が同じ組成で構成されていることを特徴とする請求項1記載の半導体装置。
- 前記第1のn型導電層と、前記p型導電層と、の組成には、InyGa1-yN(但し、yは、0<y≦1)を含んでいることを特徴とする請求項5記載の半導体装置。
- 前記第1のn型導電層と前記p型導電層との間に、組成が連続的あるいは段階的に変化する組成変調層を有することを特徴とする請求項1から請求項4の何れかの請求項に記載の半導体装置。
- 前記組成変調層は、n型またはp型の組成変調層であることを特徴とする請求項7記載の半導体装置。
- 前記p型導電層の厚さをLch、不純物濃度をNaとし、前記第1のn型導電層の厚さをLdr、不純物濃度をNdとした場合、Lch>Ldr×Nd/Naの条件を満たすことを特徴とする請求項1から請求項8の何れかの請求項に記載の半導体装置。
- 前記p型導電層の厚さをLch、不純物濃度をNaとし、前記第1のn型導電層の厚さをLdr、不純物濃度をNdとし、前記p型導電層の分極電荷密度をNpとした場合、Lch>(Ldr×Nd-Np)/Naの条件を満たすことを特徴とする請求項2から請求項4の何れかの請求項に記載の半導体装置。
- 基板上に第1のn型導電層、p型導電層、第2のn型導電層を形成し、
前記基板下面には、前記第1のn型導電層と接続するようにドレイン電極を形成し、
前記基板上面には、前記第2のn型導電層とオーム性接触するようにソース電極を形成し、
前記第1のn型導電層、前記p型導電層、前記第2のn型導電層に絶縁膜を介してゲート電極を接続し、前記ゲート電極と前記ソース電極とを交互に配置し、
前記p型導電層は、Inを含んで構成することを特徴とする半導体装置の製造方法。 - 基板上に第1のn型導電層、p型導電層、第2のn型導電層を形成し、
前記基板下面には、前記第1のn型導電層と接続するようにドレイン電極を形成し、
前記基板上面には、前記第2のn型導電層とオーム性接触するようにソース電極を形成し、
前記第1のn型導電層、前記p型導電層、前記第2のn型導電層に絶縁膜を介してゲート電極を接続し、前記ゲート電極と前記ソース電極とを交互に配置し、
前記p型導電層は、前記第1のn型導電層側に正、前記第2のn型導電層側に負の分極電荷が存在するように構成することを特徴とする半導体装置の製造方法。
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