US20230335470A1 - Semiconductor device - Google Patents
Semiconductor device Download PDFInfo
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- US20230335470A1 US20230335470A1 US18/337,919 US202318337919A US2023335470A1 US 20230335470 A1 US20230335470 A1 US 20230335470A1 US 202318337919 A US202318337919 A US 202318337919A US 2023335470 A1 US2023335470 A1 US 2023335470A1
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 113
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims abstract description 148
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical group [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 22
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 22
- 239000012535 impurity Substances 0.000 claims description 16
- 239000010410 layer Substances 0.000 description 259
- 239000011229 interlayer Substances 0.000 description 18
- 238000010586 diagram Methods 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000017525 heat dissipation Effects 0.000 description 4
- 230000001681 protective effect Effects 0.000 description 4
- 229910052814 silicon oxide Inorganic materials 0.000 description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 229910052785 arsenic Inorganic materials 0.000 description 3
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 230000020169 heat generation Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 210000000746 body region Anatomy 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000006467 substitution reaction 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
- H01L29/7803—Vertical DMOS transistors, i.e. VDMOS transistors structurally associated with at least one other device
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
- H01L23/482—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of lead-in layers inseparably applied to the semiconductor body
- H01L23/4824—Pads with extended contours, e.g. grid structure, branch structure, finger structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
- H01L23/482—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of lead-in layers inseparably applied to the semiconductor body
- H01L23/4827—Materials
-
- 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
- H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
- H01L29/0603—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions
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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
- H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
- H01L29/1608—Silicon carbide
-
- 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
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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
- H01L29/7803—Vertical DMOS transistors, i.e. VDMOS transistors structurally associated with at least one other device
- H01L29/7804—Vertical DMOS transistors, i.e. VDMOS transistors structurally associated with at least one other device the other device being a pn-junction diode
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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
- H01L29/86—Types of semiconductor device ; Multistep manufacturing processes therefor controllable only by variation of the electric current supplied, or only the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched
- H01L29/861—Diodes
Definitions
- Embodiments described herein relate generally to semiconductor devices.
- a gate resistance component may be connected to a gate electrode pad of each transistor chip. By connecting the gate resistance component, for example, suppression of resonance between the transistor chips and uniform current flow in the power module are implemented.
- a gate resistor may be embedded in the transistor chip.
- FIG. 1 is a schematic cross-sectional view of a portion of a semiconductor device according to a first embodiment
- FIG. 2 is a schematic top view of the semiconductor device according to the first embodiment
- FIG. 3 is a schematic top view of a portion of the semiconductor device according to the first embodiment
- FIG. 4 is a schematic cross-sectional view of a portion of the semiconductor device according to the first embodiment
- FIG. 5 is a schematic top view of a portion of a semiconductor device according to a second embodiment
- FIG. 6 is a schematic top view of a portion of a semiconductor device according to a third embodiment
- FIG. 7 is a schematic cross-sectional view of a portion of the semiconductor device according to the third embodiment.
- FIG. 8 is a schematic top view of a portion of a semiconductor device according to a fourth embodiment.
- FIG. 9 is a schematic cross-sectional view of a portion of the semiconductor device according to the fourth embodiment.
- FIG. 10 is a schematic cross-sectional view of a portion of the semiconductor device according to the fourth embodiment.
- FIG. 11 is an explanatory diagram of functions and effects of the semiconductor device according to the fourth embodiment.
- FIG. 12 is a schematic top view of a portion of a semiconductor device according to a fifth embodiment.
- semiconductor device including: a semiconductor layer having a first face and a second face facing the first face; a first electrode provided on a side of the first face of the semiconductor layer; a second electrode provided on a side of the second face of the semiconductor layer; a gate electrode provided on the side of the first face of the semiconductor layer; an electrode pad being provided on the side of the first face of the semiconductor layer; a wiring layer provided on the side of the first face of the semiconductor layer and electrically connected to the gate electrode; a first polycrystalline silicon layer provided on the side of the first face of the semiconductor layer, the first polycrystalline silicon layer electrically connected to the electrode pad and the wiring layer, and the first polycrystalline silicon layer extending in a first direction parallel to the first face; and an insulating layer provided between the first polycrystalline silicon layer and the electrode pad, the insulating layer provided between the first polycrystalline silicon layer and the wiring layer, and the insulating layer having at least one first opening and at least one second opening, wherein the electrode pad and the first polycrystalline silicon layer are electrically
- a semiconductor device includes: a semiconductor layer having a first face and a second face facing the first face; a first electrode provided on a side of the first face of the semiconductor layer; a second electrode provided on a side of the second face of the semiconductor layer; a gate electrode provided on the side of the first face of the semiconductor layer; an electrode pad being provided on the side of the first face of the semiconductor layer; a wiring layer provided on the side of the first face of the semiconductor layer and electrically connected to the gate electrode; a first polycrystalline silicon layer provided on the side of the first face of the semiconductor layer, the first polycrystalline silicon layer electrically connected to the electrode pad and the wiring layer, and the first polycrystalline silicon layer extending in a first direction parallel to the first face; and an insulating layer provided between the first polycrystalline silicon layer and the electrode pad, the insulating layer provided between the first polycrystalline silicon layer and the wiring layer, and the insulating layer having at least one first opening and at least one second opening.
- the electrode pad and the first polycrystalline silicon layer are electrically connected via an inside of the at least one first opening.
- the wiring layer and the first polycrystalline silicon layer are electrically connected via an inside of the at least one second opening.
- a first opening area of the at least one first opening is larger than a second opening area of the at least one second opening.
- the semiconductor device according to the first embodiment is a MOSFET 100 .
- the MOSFET 100 is a double implantation MOSFET (DIMOSFET) in which a base region and a source region are formed by ion implantation.
- the MOSFET 100 is an n-channel MOSFET having electrons as carriers.
- FIG. 1 is a schematic cross-sectional view of a portion of the semiconductor device according to the first embodiment.
- FIG. 2 is a schematic top view of the semiconductor device according to the first embodiment.
- FIG. 1 is a cross-sectional view taken along line AA′ of FIG. 2 .
- FIG. 2 illustrates the overall layout on a first face P 1 of FIG. 1 .
- the MOSFET 100 includes a silicon carbide layer 10 (semiconductor layer), a source electrode 12 (first electrode), a drain electrode 14 (second electrode), a gate electrode 16 , a gate insulating layer 18 , and an interlayer insulating layer 20 (insulating layer).
- the silicon carbide layer 10 includes an n + -type drain region 22 , an n ⁇ -type drift region 24 , a p-type body region 26 , an n + -type source region 28 , and a p + -type contact region 30 .
- the silicon carbide layer 10 is disposed between the source electrode 12 and the drain electrode 14 .
- the silicon carbide layer 10 includes a first face (“P 1 ” in FIG. 1 ) and a second face (“P 2 ” in FIG. 1 ).
- the second face P 2 faces the first face P 1 .
- the second face P 2 is parallel to the first face P 1 .
- a first direction and a second direction are directions parallel to the first face P 1 .
- the second direction is a direction perpendicular to the first direction.
- the source electrode 12 is provided on a side of the first face P 1 of the silicon carbide layer 10 .
- the source electrode 12 is provided on the first face P 1 of the silicon carbide layer 10 .
- the source electrode 12 is in contact with the first face P 1 .
- the source electrode 12 is made of, for example, a metal.
- the source electrode 12 is electrically connected to the source region 28 and the contact region 30 .
- the source electrode 12 is in contact with, for example, the source region 28 and the contact region 30 .
- the drain electrode 14 is disposed on a side of the second face P 2 of the silicon carbide layer 10 .
- the drain electrode 14 is provided on the second face P 2 of the silicon carbide layer 10 .
- the drain electrode 14 is in contact with the second face P 2 .
- the drain electrode 14 is made of, for example, a metal or a metal semiconductor compound.
- the drain electrode 14 is electrically connected to the drain region 22 .
- the drain electrode 14 is in contact with, for example, the drain region 22 .
- the gate electrode 16 is disposed on the side of the first face P 1 of the silicon carbide layer 10 .
- the gate electrode 16 extends in, for example, the second direction.
- the gate electrode 16 is a conductive layer.
- the gate electrode 16 is made of, for example, polycrystalline silicon containing p-type impurities or n-type impurities.
- the gate insulating layer 18 is disposed between the gate electrode 16 and the silicon carbide layer 10 .
- the gate insulating layer 18 is, for example, a silicon oxide film.
- the interlayer insulating layer 20 is provided on the gate electrode 16 .
- the interlayer insulating layer 20 is provided between the gate electrode 16 and the source electrode 12 .
- the interlayer insulating layer 20 electrically separates the gate electrode 16 and the source electrode 12 .
- the interlayer insulating layer 20 is, for example, a silicon oxide film.
- the MOSFET 100 includes the source electrode 12 (first electrode), a gate electrode pad 32 (electrode pad), and a gate wiring layer 34 (wiring layer).
- the gate electrode pad 32 is provided on the side of the first face P 1 of the silicon carbide layer 10 .
- a bonding wire can be connected on the gate electrode pad 32 .
- the gate electrode pad 32 is connected to, for example, a gate driver circuit by using the bonding wire.
- a gate voltage is applied to the gate electrode pad 32 from the gate driver circuit via the bonding wire.
- the gate electrode pad 32 is made of, for example, the same material as the source electrode 12 .
- the gate electrode pad 32 is formed in, for example, the same layer as the source electrode 12 .
- the gate electrode pad 32 is made of, for example, a metal.
- the gate wiring layer 34 is provided on the side of the first face P 1 of the silicon carbide layer 10 .
- the gate wiring layer 34 is made of, for example, the same material as the source electrode 12 and the gate electrode pad 32 .
- the gate electrode pad 32 is formed in, for example, the same layer as the source electrode 12 and the gate electrode pad 32 .
- the gate electrode pad 32 is made of, for example, a metal.
- a portion of the gate wiring layer 34 is provided adjacent to, for example, the gate electrode pad 32 .
- a portion of the gate wiring layer 34 is provided along, for example, the gate electrode pad 32 .
- the gate wiring layer 34 is electrically connected to the gate electrode 16 .
- FIG. 3 is a schematic top view of a portion of the semiconductor device according to the first embodiment.
- FIG. 3 illustrates a pattern layout of a region X surrounded by a broken line in FIG. 2 .
- FIG. 4 is a schematic cross-sectional view of a portion of the semiconductor device according to the first embodiment.
- FIG. 4 is a cross-sectional view taken along line BB′ of FIG. 3 .
- the MOSFET 100 includes a silicon carbide layer 10 (semiconductor layer), a source electrode 12 (first electrode), an interlayer insulating layer 20 (insulating layer), a gate electrode pad 32 (electrode pad), a gate wiring layer 34 (wiring layer), a plurality of first polycrystalline silicon layers 41 , and a field insulating layer 44 .
- the interlayer insulating layer 20 has a first contact hole 20 a (first opening) and a second contact hole 20 b (second opening).
- the field insulating layer 44 is provided on the silicon carbide layer 10 .
- the field insulating layer 44 is, for example, a silicon oxide film.
- the first polycrystalline silicon layer 41 is provided on the silicon carbide layer 10 .
- the first polycrystalline silicon layer 41 is provided on the field insulating layer 44 .
- the first polycrystalline silicon layer 41 is electrically connected to the gate electrode pad 32 and the gate wiring layer 34 .
- the gate electrode pad 32 , the first polycrystalline silicon layer 41 , the gate wiring layer 34 , and the gate electrode 16 are connected in series.
- the first polycrystalline silicon layer 41 functions as a gate resistor embedded in the MOSFET 100 .
- the first polycrystalline silicon layer 41 extends in the first direction.
- a length (L in FIG. 3 ) of the first polycrystalline silicon layer 41 in the first direction is, for example, 200 ⁇ m or more and 500 ⁇ m or less.
- a width (W in FIG. 3 ) of the first polycrystalline silicon layer 41 in the second direction is, for example, 20 ⁇ m or more and 50 ⁇ m or less.
- the first polycrystalline silicon layer 41 contains p-type impurities or n-type impurities.
- the p-type impurity is, for example, boron (B).
- the n-type impurity is, for example, phosphorus (P) or arsenic (As).
- the first polycrystalline silicon layer 41 is made of, for example, the same material as the gate electrode 16 .
- the first polycrystalline silicon layer 41 is formed in, for example, the same layer as the gate electrode 16 .
- the interlayer insulating layer 20 is provided between the first polycrystalline silicon layer 41 and the gate electrode pad 32 .
- the interlayer insulating layer 20 is provided between the first polycrystalline silicon layer 41 and the gate wiring layer 34 .
- the interlayer insulating layer 20 has a first contact hole 20 a and a second contact hole 20 b .
- the first contact hole 20 a and the second contact hole 20 b have hole patterns provided in the interlayer insulating layer 20 .
- a first opening area of the first contact hole 20 a is larger than a second opening area of the second contact hole 20 b .
- the first opening area is, for example, twice or more and ten times or less of the second opening area.
- the first opening area of the first contact hole 20 a denotes an area of a region surrounded by a wall surface of the first contact hole 20 a among the surfaces parallel to the first face P 1 .
- the first opening area of the first contact hole 20 a is, for example, the area of a square illustrated the first contact hole 20 a in FIG. 3 .
- the second opening area of the second contact hole 20 b denotes an area of a region surrounded by a wall surface of the second contact hole 20 b among the surfaces parallel to the first face P 1 .
- the second opening area of the second contact hole 20 b is, for example, the area of a square illustrated the second contact hole 20 b in FIG. 3 .
- the gate electrode pad 32 and the first polycrystalline silicon layer 41 are electrically connected via the first contact hole 20 a .
- the gate electrode pad 32 entering the first contact hole 20 a is in contact with the first polycrystalline silicon layer 41 at the bottom of the first contact hole 20 a , the gate electrode pad 32 and the first polycrystalline silicon layer 41 are electrically connected.
- the gate wiring layer 34 and the first polycrystalline silicon layer 41 are electrically connected via the second contact hole 20 b .
- the gate wiring layer 34 entering the second contact hole 20 b is in contact with the first polycrystalline silicon layer 41 at the bottom of the second contact hole 20 b , the gate wiring layer 34 and the first polycrystalline silicon layer 41 are electrically connected.
- a distance (d in FIG. 3 ) between the first contact hole 20 a and the second contact hole 20 b is, for example, 100 ⁇ m or more and 300 ⁇ m or less.
- a gate resistance component may be connected to the gate electrode pad of each transistor chip. By connecting the gate resistance component, for example, suppression of resonance between the transistor chips and uniform current in the power module are implemented.
- the gate resistance component In a case where the gate resistance component is connected outside the transistor chip, problems such as an increase in size of the power module and a loss of the degree of freedom in arrangement of the transistor chips in the power module occur. For this reason, in some cases, the gate resistor may be embedded in the transistor chip.
- the resistance value of the gate resistor changes by the temperature rise due to the heat generation of the gate resistor, and thus, the fluctuation in characteristics of the transistor occurs.
- the gate resistor is melted and cut, and thus, the transistor is destructed.
- the first opening area of the first contact hole 20 a for connecting the gate electrode pad 32 and the first polycrystalline silicon layer 41 is larger than the second opening area of the second contact hole 20 b for connecting the gate wiring layer 34 and the first polycrystalline silicon layer 41 .
- the heat generated in the first polycrystalline silicon layer 41 easily flows to the gate electrode pad 32 .
- the gate electrode pad 32 has a larger area than the gate wiring layer 34 . For this reason, the gate electrode pad 32 has a higher heat dissipation efficiency than the gate wiring layer 34 .
- a bonding wire is connected to the gate electrode pad 32 . For this reason, the gate electrode pad 32 can be expected to dissipate heat through the bonding wire.
- a protective film is not formed. Therefore, the heat dissipation efficiency is higher than that of the gate wiring layer 34 on which the protective film is formed.
- the heat generated in the first polycrystalline silicon layer 41 more easily flows to the gate electrode pad 32 than the gate wiring layer 34 , so that the temperature rise of the first polycrystalline silicon layer 41 is suppressed. Therefore, the fluctuation in characteristics and destruction of the MOSFET 100 are suppressed.
- the first opening area is preferably twice or more, more preferably four times or more of the second opening area.
- the first embodiment it is possible to provide a semiconductor device in which the temperature rise of the embedded gate resistor is suppressed.
- a semiconductor device according to a second embodiment is different from the semiconductor device according to the first embodiment in that the number of at least one first opening is larger than the number of at least one second opening.
- the semiconductor device according to the second embodiment is a MOSFET 200 .
- FIG. 5 is a schematic top view of a portion of the semiconductor device according to the second embodiment.
- FIG. 5 is a diagram corresponding to FIG. 3 of the first embodiment.
- the number of first contact holes 20 a is larger than the number of second contact holes 20 b .
- the number of first contact holes 20 a corresponding to one first polycrystalline silicon layer 41 is four, and the number of second contact holes 20 b is one.
- a first opening area of the first contact holes 20 a is the sum of the opening areas of the individual first contact holes 20 a .
- a second opening area of the second contact holes 20 b is the sum of the opening areas of the individual second contact holes 20 b.
- the first opening area of the first contact hole 20 a is four times of the second opening area of the second contact hole 20 b.
- the semiconductor device in which a temperature rise of an embedded gate resistor is suppressed.
- a semiconductor device is different from the semiconductor device according to the first embodiment in that the semiconductor device according to the third embodiment further includes a second polycrystalline silicon layer provided on a side of a first face of a semiconductor layer, the second polycrystalline silicon layer electrically connected to an electrode pad, the second polycrystalline silicon layer electrically separated from a wiring layer, and the second polycrystalline silicon layer extending in a first direction.
- the semiconductor device according to the third embodiment further includes a second polycrystalline silicon layer provided on a side of a first face of a semiconductor layer, the second polycrystalline silicon layer electrically connected to an electrode pad, the second polycrystalline silicon layer electrically separated from a wiring layer, and the second polycrystalline silicon layer extending in a first direction.
- the semiconductor device according to the third embodiment is a MOSFET 300 .
- FIG. 6 is a schematic top view of a portion of the semiconductor device according to the third embodiment.
- FIG. 6 is a diagram corresponding to FIG. 3 of the first embodiment.
- FIG. 7 is a schematic cross-sectional view of a portion of the semiconductor device according to the third embodiment.
- FIG. 7 is a cross-sectional view taken along line CC′ of FIG. 6 .
- the MOSFET 300 includes a second polycrystalline silicon layer 42 in addition to a first polycrystalline silicon layer 41 .
- the second polycrystalline silicon layer 42 is provided on the side of a first face P 1 of a silicon carbide layer 10 .
- the second polycrystalline silicon layer 42 extends in the first direction.
- the second polycrystalline silicon layer 42 is electrically connected to a gate electrode pad 32 .
- the second polycrystalline silicon layer 42 is electrically separated from a gate wiring layer 34 .
- a contact hole for electrically connecting the gate wiring layer 34 and the second polycrystalline silicon layer 42 is not provided to an interlayer insulating layer 20 .
- the MOSFET 300 according to the third embodiment includes the second polycrystalline silicon layer 42 which is electrically separated from a gate wiring layer 34 , it is possible to set a gate resistor to have a higher resistance value than that of the MOSFET 100 according to the first embodiment.
- the semiconductor device in which a temperature rise of the embedded gate resistor is suppressed.
- a semiconductor device includes: a semiconductor layer having a first face and a second face facing the first face; a first electrode being provided on a side of the first face of the semiconductor layer; a second electrode being provided on a side of the second face of the semiconductor layer; a gate electrode being provided on the side of the first face of the semiconductor layer; an electrode pad being provided on the side of the first face of the semiconductor layer; a wiring layer being provided on the side of the first face of the semiconductor layer and being electrically connected to the gate electrode; a first polycrystalline silicon layer being provided on the side of the first face of the semiconductor layer, being electrically connected to the electrode pad and the wiring layer, extending in a first direction parallel to the first face, and including a first p-type region and a first n-type region; a second polycrystalline silicon layer being provided on the side of the first face of the semiconductor layer, being electrically connected to the electrode pad and the wiring layer, extending in the first direction, including a second n-type region and a second p-type
- the semiconductor device according to the fourth embodiment is a MOSFET 400 .
- the MOSFET 400 has a transistor structure similar to the structure illustrated in FIG. 1 of the first embodiment.
- FIG. 8 is a schematic top view of a portion of the semiconductor device according to the fourth embodiment.
- FIG. 8 is a diagram corresponding to FIG. 3 of the first embodiment.
- FIG. 9 is a schematic cross-sectional view of a portion of the semiconductor device according to the fourth embodiment.
- FIG. 9 is a cross-sectional view taken along line DD′ of FIG. 8 .
- FIG. 10 is a schematic cross-sectional view of a portion of the semiconductor device according to the fourth embodiment.
- FIG. 10 is a cross-sectional view taken along line EE′ of FIG. 8 .
- the MOSFET 400 includes a silicon carbide layer 10 (semiconductor layer), a source electrode 12 (first electrode), an interlayer insulating layer 20 (insulating layer), a gate electrode pad 32 (electrode pad), a gate wiring layer 34 (wiring layer), a plurality of first polycrystalline silicon layers 51 , a plurality of second polycrystalline silicon layers 52 , and a field insulating layer 44 .
- the interlayer insulating layer 20 includes a first contact hole 20 a (first opening), a second contact hole 20 b (second opening), a third contact hole 20 c (third opening), and a fourth contact hole 20 d (fourth opening).
- the field insulating layer 44 is provided on the silicon carbide layer 10 .
- the field insulating layer 44 is, for example, a silicon oxide film.
- the first polycrystalline silicon layer 51 and the second polycrystalline silicon layer 52 are provided on the silicon carbide layer 10 .
- the first polycrystalline silicon layer 51 and the second polycrystalline silicon layer 52 are provided on the field insulating layer 44 .
- the first polycrystalline silicon layer 51 and the second polycrystalline silicon layer 52 are electrically connected to the gate electrode pad 32 and the gate wiring layer 34 .
- the gate electrode pad 32 , the first polycrystalline silicon layer 51 , the gate wiring layer 34 , and the gate electrode 16 are connected in series.
- the gate electrode pad 32 , the second polycrystalline silicon layer 52 , the gate wiring layer 34 , and the gate electrode 16 are connected in series.
- the first polycrystalline silicon layer 51 and the second polycrystalline silicon layer 52 function as gate resistors embedded in the MOSFET 400 .
- the first polycrystalline silicon layer 51 extends in the first direction.
- a length of the first polycrystalline silicon layer 51 in the first direction is, for example, 200 ⁇ m or more and 500 ⁇ m or less.
- a width of the first polycrystalline silicon layer 51 in the second direction is, for example, 20 ⁇ m or more and 50 ⁇ m or less.
- the first polycrystalline silicon layer 51 includes a first p-type region 51 a and a first n-type region 51 b .
- the first polycrystalline silicon layer 51 functions as a gate resistor with a pn diode.
- the first p-type region 51 a contains p-type impurities.
- the p-type impurity is, for example, boron (B).
- the first n-type region 51 b contains n-type impurities.
- the n-type impurity is, for example, phosphorus (P) or arsenic (As).
- the second polycrystalline silicon layer 52 extends in the first direction.
- the second polycrystalline silicon layer 52 is separated from the first polycrystalline silicon layer 51 .
- a length of the second polycrystalline silicon layer 52 in the first direction is, for example, 200 ⁇ m or more and 500 ⁇ m or less.
- a width of the second polycrystalline silicon layer 52 in the second direction is, for example, 20 ⁇ m or more and 50 ⁇ m or less.
- the second polycrystalline silicon layer 52 includes a second n-type region 52 a and a second p-type region 52 b .
- the second polycrystalline silicon layer 52 functions as a gate resistor with a pn diode.
- the second n-type region 52 a contains n-type impurities.
- the n-type impurity is, for example, phosphorus (P) or arsenic (As).
- the second p-type region 52 b contains p-type impurities.
- the p-type impurity is, for example, boron (B).
- the interlayer insulating layer 20 is provided between the first polycrystalline silicon layer 51 and the gate electrode pad 32 and between the second polycrystalline silicon layer 52 and the gate electrode pad 32 .
- the interlayer insulating layer 20 is provided between the first polycrystalline silicon layer 51 and the gate wiring layer 34 and between the second polycrystalline silicon layer 52 and the gate wiring layer 34 .
- the interlayer insulating layer 20 has a first contact hole 20 a , a second contact hole 20 b , a third contact hole 20 c , and a fourth contact hole 20 d .
- the first contact hole 20 a , the second contact hole 20 b , the third contact hole 20 c , and the fourth contact hole 20 d are hole patterns provided in the interlayer insulating layer 20 .
- the gate electrode pad 32 and the first p-type region 51 a are electrically connected via the first contact hole 20 a .
- the gate electrode pad 32 entering the first contact hole 20 a is in contact with the first p-type region 51 a at the bottom of the first contact hole 20 a , the gate electrode pad 32 and the first p-type region 51 a are electrically connected.
- the gate wiring layer 34 and the first n-type region 51 b are electrically connected via the second contact hole 20 b .
- the gate wiring layer 34 entering the second contact hole 20 b is in contact with the first n-type region 51 b at the bottom of the second contact hole 20 b , the gate wiring layer 34 and the first n-type region 51 b are electrically connected.
- a distance between the first contact hole 20 a and the second contact hole 20 b is, for example, 100 ⁇ m or more and 300 ⁇ m or less.
- a boundary between the first p-type region 51 a and the first n-type region 51 b is a first junction plane 51 x .
- the first junction plane 51 x is a pn junction.
- a first distance (d 1 in FIG. 8 ) between the first junction plane 51 x and the first contact hole 20 a is smaller than a second distance (d 2 in FIG. 8 ) between the first junction plane 51 x and the second contact hole 20 b .
- the first distance d 1 is, for example, one-half or less of the second distance d 2 .
- the gate electrode pad 32 and the second n-type region 52 a are electrically connected via the third contact hole 20 c .
- the gate electrode pad 32 entering the third contact hole 20 c is in contact with the second n-type region 52 a at the bottom of the third contact hole 20 c , the gate electrode pad 32 and the second n-type region 52 a are electrically connected.
- the gate wiring layer 34 and the second p-type region 52 b are electrically connected via the fourth contact hole 20 d .
- the gate wiring layer 34 entering the fourth contact hole 20 d is in contact with the second p-type region 52 b at the bottom of the fourth contact hole 20 d , the gate wiring layer 34 and the second p-type region 52 b are electrically connected.
- a distance between the third contact hole 20 c and the fourth contact hole 20 d is, for example, 100 ⁇ m or more and 300 ⁇ m or less.
- a boundary between the second n-type region 52 a and the second p-type region 52 b is a second junction plane 52 x .
- the second junction plane 52 x is a pn junction.
- a third distance (d 3 in FIG. 8 ) between the second junction plane 52 x and the third contact hole 20 c is smaller than a fourth distance (d 4 in FIG. 8 ) between the second junction plane 52 x and the fourth contact hole 20 d .
- the third distance d 3 is, for example, one-half or less of the fourth distance d 4 .
- FIG. 11 is an explanatory diagram of functions and effects of the semiconductor device according to the fourth embodiment.
- FIG. 11 illustrates an equivalent circuit diagram including the gate resistors of the MOSFET 400 .
- different resistance values of the gate resistor can be applied at the time of the turn-on operation of the transistor and at the time of the turn-off operation of the transistor.
- an optimum resistance value of the gate resistor can be applied at the time of the turn-on operation of the transistor and at the time of the turn-off operation of the transistor.
- the number of first polycrystalline silicon layers 51 connected in parallel is two, and the number of second polycrystalline silicon layers 52 connected in parallel is four.
- the resistance value at the time of the turn-on operation of the transistor is larger than the resistance value at the time of the turn-off operation.
- the resonance between the transistor chips can be suppressed.
- a turn-off loss can be reduced by decreasing the resistance value at the time of the turn-off operation of the transistor.
- the temperature of the first polycrystalline silicon layer 51 or the second polycrystalline silicon layer 52 rises due to the heat generated by the diode, and thus, there is a concern that a fluctuation in characteristics of the transistor occurs or the transistor is destructed.
- the first distance (d 1 in FIG. 8 ) between the first junction plane 51 x and the first contact hole 20 a is smaller than the second distance (d 2 in FIG. 8 ) between the first junction plane 51 x and the second contact hole 20 b .
- the first contact hole 20 a connected to the gate electrode pad 32 is provided at a location close to the pn junction of the diode.
- the heat generated by the diode of the first polycrystalline silicon layer 51 easily flows to the gate electrode pad 32 .
- the third distance (d 3 in FIG. 8 ) between the second junction plane 52 x and the third contact hole 20 c is smaller than the fourth distance (d 4 in FIG. 8 ) between the second junction plane 52 x and the fourth contact hole 20 d .
- the third contact hole 20 c connected to the gate electrode pad 32 is provided at a location close to the pn junction of the diode.
- the heat generated by the diode of the second polycrystalline silicon layer 52 easily flows to the gate electrode pad 32 .
- the gate electrode pad 32 has a larger area than the gate wiring layer 34 . For this reason, the gate electrode pad 32 has a higher heat dissipation efficiency than the gate wiring layer 34 .
- a bonding wire is connected to the gate electrode pad 32 .
- the gate electrode pad 32 can be expected to dissipate heat through the bonding wire.
- a protective film is not formed on the gate electrode pad 32 for performing bonding. Therefore, the heat dissipation efficiency is higher than that of the gate wiring layer 34 on which the protective film is formed.
- the heat generated by the diodes of the first polycrystalline silicon layer 51 and the second polycrystalline silicon layer 52 easily flows to the gate electrode pad 32 , so that a temperature rise of the first polycrystalline silicon layer 51 and the second polycrystalline silicon layer 52 is suppressed. Therefore, the fluctuation in characteristics and the of the MOSFET 400 are suppressed.
- the first distance d 1 is preferably one-half or less of the second distance d 2 , more preferably one-fourth or less of the second distance d 2 .
- the third distance d 3 is preferably one-half or less of the fourth distance d 4 , more preferably one-fourth or less of the fourth distance d 4 .
- the case of changing the resistance value at the time of the turn-on operation of the transistor and the resistance value at the time of the turn-off operation of the transistor by changing the number of the first polycrystalline silicon layers 51 and the number of the second polycrystalline silicon layers 52 connected in parallel has been described as an example.
- the resistance value at the time of the turn-on operation of the transistor and the resistance value at the time of the turn-off operation of the transistor may be allowed to be changed by changing the resistance value of each of the first polycrystalline silicon layer 51 and the second polycrystalline silicon layer 52 .
- the resistance value at the time of the turn-on operation of the transistor is allowed to be larger than the resistance value at the time of the turn-off operation is described as an example, but the resistance value at the time of the turn-on operation of the transistor may be allowed to be smaller than the resistance value at the time of the turn-off operation.
- the fourth embodiment it is possible to provide a semiconductor device in which the temperature rise of the embedded gate resistor is suppressed.
- a semiconductor device is different from the semiconductor device according to the fourth embodiment in that a first opening area of at least one first opening is larger than a second opening area of at least one second opening, and a third opening area of at least one third opening is larger than a fourth opening area of at least one fourth opening.
- a first opening area of at least one first opening is larger than a second opening area of at least one second opening
- a third opening area of at least one third opening is larger than a fourth opening area of at least one fourth opening.
- the semiconductor device according to the fifth embodiment is a MOSFET 500 .
- FIG. 12 is a schematic top view of a portion of the semiconductor device according to the fifth embodiment.
- FIG. 12 is a diagram corresponding to FIG. 8 of the fourth embodiment.
- a first opening area of a first contact hole 20 a is larger than a second opening area of a second contact hole 20 b . Since the first opening area of the first contact hole 20 a is large, the heat generated in a first polycrystalline silicon layer 51 easily flows to a gate electrode pad 32 .
- a third opening area of a third contact hole 20 c is larger than a fourth opening area of a fourth contact hole 20 d . Since the third opening area of the third contact hole 20 c is large, the heat generated in a second polycrystalline silicon layer 52 easily flows to a gate electrode pad 32 .
- the MOSFET 500 according to the fifth embodiment can further suppress a temperature rise of the first polycrystalline silicon layer 51 and the second polycrystalline silicon layer 52 as compared with the MOSFET 400 according to the fourth embodiment.
- the semiconductor device in which a temperature rise of an embedded gate resistor is suppressed.
- the n-channel MOSFETs are described as examples, but the embodiments can also be applied to p-channel MOSFETs.
- the MOSFETs having a planar gate structure in which a gate electrode is provided on a first face of a semiconductor layer are described as examples, but the embodiments can also be applied to MOSFETs having a trench gate structure in which the gate electrode is provided in a trench formed in the semiconductor layer.
- the embodiments can also be applied to an insulated gate bipolar transistor (IGBT).
- IGBT insulated gate bipolar transistor
- the semiconductor layer may be another semiconductor such as silicon.
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Abstract
According to an embodiment, provided is a semiconductor device includes a semiconductor layer; a first electrode; a second electrode; an electrode pad; a wiring layer electrically connected to the gate electrode; a first polycrystalline silicon layer electrically connected to the electrode pad and the wiring layer; and an insulating layer provided between the first polycrystalline silicon layer and the electrode pad and between the first polycrystalline silicon layer and the wiring layer and having a first opening and a second opening. The electrode pad and the first polycrystalline silicon layer are electrically connected via an inside of the first opening. The wiring layer and the first polycrystalline silicon layer are electrically connected via an inside of the second opening, A first opening area of the first opening is larger than a second opening area of the second opening.
Description
- This application is a continuation of U.S. patent application Ser. No. 17/193,765, filed on Mar. 5, 2021, which is based upon and claims the benefit of priority from Japanese Patent Application No. 2020-157962, filed on Sep. 18, 2020, the entire contents of which are incorporated herein by reference.
- Embodiments described herein relate generally to semiconductor devices.
- In a power module in which a plurality of transistor chips are mounted on a substrate, a gate resistance component may be connected to a gate electrode pad of each transistor chip. By connecting the gate resistance component, for example, suppression of resonance between the transistor chips and uniform current flow in the power module are implemented.
- In a case where the gate resistance component is connected outside the transistor chip, problems such as an increase in size of the power module and a loss of degree of the freedom in arrangement of the transistor chips in the power module occur. For this reason, in some cases, a gate resistor may be embedded in the transistor chip.
-
FIG. 1 is a schematic cross-sectional view of a portion of a semiconductor device according to a first embodiment; -
FIG. 2 is a schematic top view of the semiconductor device according to the first embodiment; -
FIG. 3 is a schematic top view of a portion of the semiconductor device according to the first embodiment; -
FIG. 4 is a schematic cross-sectional view of a portion of the semiconductor device according to the first embodiment; -
FIG. 5 is a schematic top view of a portion of a semiconductor device according to a second embodiment; -
FIG. 6 is a schematic top view of a portion of a semiconductor device according to a third embodiment; -
FIG. 7 is a schematic cross-sectional view of a portion of the semiconductor device according to the third embodiment; -
FIG. 8 is a schematic top view of a portion of a semiconductor device according to a fourth embodiment; -
FIG. 9 is a schematic cross-sectional view of a portion of the semiconductor device according to the fourth embodiment; -
FIG. 10 is a schematic cross-sectional view of a portion of the semiconductor device according to the fourth embodiment; -
FIG. 11 is an explanatory diagram of functions and effects of the semiconductor device according to the fourth embodiment; and -
FIG. 12 is a schematic top view of a portion of a semiconductor device according to a fifth embodiment. - According to an embodiment, there is provided semiconductor device including: a semiconductor layer having a first face and a second face facing the first face; a first electrode provided on a side of the first face of the semiconductor layer; a second electrode provided on a side of the second face of the semiconductor layer; a gate electrode provided on the side of the first face of the semiconductor layer; an electrode pad being provided on the side of the first face of the semiconductor layer; a wiring layer provided on the side of the first face of the semiconductor layer and electrically connected to the gate electrode; a first polycrystalline silicon layer provided on the side of the first face of the semiconductor layer, the first polycrystalline silicon layer electrically connected to the electrode pad and the wiring layer, and the first polycrystalline silicon layer extending in a first direction parallel to the first face; and an insulating layer provided between the first polycrystalline silicon layer and the electrode pad, the insulating layer provided between the first polycrystalline silicon layer and the wiring layer, and the insulating layer having at least one first opening and at least one second opening, wherein the electrode pad and the first polycrystalline silicon layer are electrically connected via an inside of the at least one first opening, the wiring layer and the first polycrystalline silicon layer are electrically connected via an inside of the at least one second opening, and a first opening area of the at least one first opening is larger than a second opening area of the at least one second opening.
- Hereinafter, embodiments will be described with reference to the drawings. In addition, in the following description, the same or similar components and the like will be denoted by the same reference numerals, and the description of the components and the like once described will be omitted as appropriate.
- A semiconductor device according to a first embodiment includes: a semiconductor layer having a first face and a second face facing the first face; a first electrode provided on a side of the first face of the semiconductor layer; a second electrode provided on a side of the second face of the semiconductor layer; a gate electrode provided on the side of the first face of the semiconductor layer; an electrode pad being provided on the side of the first face of the semiconductor layer; a wiring layer provided on the side of the first face of the semiconductor layer and electrically connected to the gate electrode; a first polycrystalline silicon layer provided on the side of the first face of the semiconductor layer, the first polycrystalline silicon layer electrically connected to the electrode pad and the wiring layer, and the first polycrystalline silicon layer extending in a first direction parallel to the first face; and an insulating layer provided between the first polycrystalline silicon layer and the electrode pad, the insulating layer provided between the first polycrystalline silicon layer and the wiring layer, and the insulating layer having at least one first opening and at least one second opening. The electrode pad and the first polycrystalline silicon layer are electrically connected via an inside of the at least one first opening. The wiring layer and the first polycrystalline silicon layer are electrically connected via an inside of the at least one second opening. And a first opening area of the at least one first opening is larger than a second opening area of the at least one second opening.
- The semiconductor device according to the first embodiment is a
MOSFET 100. TheMOSFET 100 is a double implantation MOSFET (DIMOSFET) in which a base region and a source region are formed by ion implantation. In addition, theMOSFET 100 is an n-channel MOSFET having electrons as carriers. -
FIG. 1 is a schematic cross-sectional view of a portion of the semiconductor device according to the first embodiment.FIG. 2 is a schematic top view of the semiconductor device according to the first embodiment. -
FIG. 1 is a cross-sectional view taken along line AA′ ofFIG. 2 .FIG. 2 illustrates the overall layout on a first face P1 ofFIG. 1 . - As illustrated in
FIG. 1 , theMOSFET 100 includes a silicon carbide layer 10 (semiconductor layer), a source electrode 12 (first electrode), a drain electrode 14 (second electrode), agate electrode 16, agate insulating layer 18, and an interlayer insulating layer 20 (insulating layer). - The
silicon carbide layer 10 includes an n+-type drain region 22, an n−-type drift region 24, a p-type body region 26, an n+-type source region 28, and a p+-type contact region 30. - The
silicon carbide layer 10 is disposed between thesource electrode 12 and thedrain electrode 14. Thesilicon carbide layer 10 includes a first face (“P1” inFIG. 1 ) and a second face (“P2” inFIG. 1 ). - The second face P2 faces the first face P1. The second face P2 is parallel to the first face P1.
- A first direction and a second direction are directions parallel to the first face P1. In addition, the second direction is a direction perpendicular to the first direction.
- The
source electrode 12 is provided on a side of the first face P1 of thesilicon carbide layer 10. Thesource electrode 12 is provided on the first face P1 of thesilicon carbide layer 10. Thesource electrode 12 is in contact with the first face P1. - The
source electrode 12 is made of, for example, a metal. Thesource electrode 12 is electrically connected to thesource region 28 and thecontact region 30. Thesource electrode 12 is in contact with, for example, thesource region 28 and thecontact region 30. - The
drain electrode 14 is disposed on a side of the second face P2 of thesilicon carbide layer 10. Thedrain electrode 14 is provided on the second face P2 of thesilicon carbide layer 10. Thedrain electrode 14 is in contact with the second face P2. - The
drain electrode 14 is made of, for example, a metal or a metal semiconductor compound. Thedrain electrode 14 is electrically connected to thedrain region 22. Thedrain electrode 14 is in contact with, for example, thedrain region 22. - The
gate electrode 16 is disposed on the side of the first face P1 of thesilicon carbide layer 10. Thegate electrode 16 extends in, for example, the second direction. - The
gate electrode 16 is a conductive layer. Thegate electrode 16 is made of, for example, polycrystalline silicon containing p-type impurities or n-type impurities. - The
gate insulating layer 18 is disposed between thegate electrode 16 and thesilicon carbide layer 10. Thegate insulating layer 18 is, for example, a silicon oxide film. - The interlayer insulating
layer 20 is provided on thegate electrode 16. The interlayer insulatinglayer 20 is provided between thegate electrode 16 and thesource electrode 12. The interlayer insulatinglayer 20 electrically separates thegate electrode 16 and thesource electrode 12. The interlayer insulatinglayer 20 is, for example, a silicon oxide film. - As illustrated in
FIG. 2 , theMOSFET 100 includes the source electrode 12 (first electrode), a gate electrode pad 32 (electrode pad), and a gate wiring layer 34 (wiring layer). - The
gate electrode pad 32 is provided on the side of the first face P1 of thesilicon carbide layer 10. A bonding wire can be connected on thegate electrode pad 32. Thegate electrode pad 32 is connected to, for example, a gate driver circuit by using the bonding wire. A gate voltage is applied to thegate electrode pad 32 from the gate driver circuit via the bonding wire. - The
gate electrode pad 32 is made of, for example, the same material as thesource electrode 12. Thegate electrode pad 32 is formed in, for example, the same layer as thesource electrode 12. Thegate electrode pad 32 is made of, for example, a metal. - The
gate wiring layer 34 is provided on the side of the first face P1 of thesilicon carbide layer 10. Thegate wiring layer 34 is made of, for example, the same material as thesource electrode 12 and thegate electrode pad 32. Thegate electrode pad 32 is formed in, for example, the same layer as thesource electrode 12 and thegate electrode pad 32. Thegate electrode pad 32 is made of, for example, a metal. - A portion of the
gate wiring layer 34 is provided adjacent to, for example, thegate electrode pad 32. A portion of thegate wiring layer 34 is provided along, for example, thegate electrode pad 32. - The
gate wiring layer 34 is electrically connected to thegate electrode 16. -
FIG. 3 is a schematic top view of a portion of the semiconductor device according to the first embodiment.FIG. 3 illustrates a pattern layout of a region X surrounded by a broken line inFIG. 2 . -
FIG. 4 is a schematic cross-sectional view of a portion of the semiconductor device according to the first embodiment.FIG. 4 is a cross-sectional view taken along line BB′ ofFIG. 3 . - As illustrated in
FIGS. 1 to 4 , theMOSFET 100 includes a silicon carbide layer 10 (semiconductor layer), a source electrode 12 (first electrode), an interlayer insulating layer 20 (insulating layer), a gate electrode pad 32 (electrode pad), a gate wiring layer 34 (wiring layer), a plurality of first polycrystalline silicon layers 41, and afield insulating layer 44. The interlayer insulatinglayer 20 has afirst contact hole 20 a (first opening) and asecond contact hole 20 b (second opening). - The
field insulating layer 44 is provided on thesilicon carbide layer 10. Thefield insulating layer 44 is, for example, a silicon oxide film. - The first
polycrystalline silicon layer 41 is provided on thesilicon carbide layer 10. The firstpolycrystalline silicon layer 41 is provided on thefield insulating layer 44. - The first
polycrystalline silicon layer 41 is electrically connected to thegate electrode pad 32 and thegate wiring layer 34. Thegate electrode pad 32, the firstpolycrystalline silicon layer 41, thegate wiring layer 34, and thegate electrode 16 are connected in series. The firstpolycrystalline silicon layer 41 functions as a gate resistor embedded in theMOSFET 100. - The first
polycrystalline silicon layer 41 extends in the first direction. A length (L inFIG. 3 ) of the firstpolycrystalline silicon layer 41 in the first direction is, for example, 200 μm or more and 500 μm or less. A width (W inFIG. 3 ) of the firstpolycrystalline silicon layer 41 in the second direction is, for example, 20 μm or more and 50 μm or less. - The first
polycrystalline silicon layer 41 contains p-type impurities or n-type impurities. The p-type impurity is, for example, boron (B). The n-type impurity is, for example, phosphorus (P) or arsenic (As). - The first
polycrystalline silicon layer 41 is made of, for example, the same material as thegate electrode 16. The firstpolycrystalline silicon layer 41 is formed in, for example, the same layer as thegate electrode 16. - The interlayer insulating
layer 20 is provided between the firstpolycrystalline silicon layer 41 and thegate electrode pad 32. The interlayer insulatinglayer 20 is provided between the firstpolycrystalline silicon layer 41 and thegate wiring layer 34. - The interlayer insulating
layer 20 has afirst contact hole 20 a and asecond contact hole 20 b. Thefirst contact hole 20 a and thesecond contact hole 20 b have hole patterns provided in theinterlayer insulating layer 20. - A first opening area of the
first contact hole 20 a is larger than a second opening area of thesecond contact hole 20 b. The first opening area is, for example, twice or more and ten times or less of the second opening area. - The first opening area of the
first contact hole 20 a denotes an area of a region surrounded by a wall surface of thefirst contact hole 20 a among the surfaces parallel to the first face P1. The first opening area of thefirst contact hole 20 a is, for example, the area of a square illustrated thefirst contact hole 20 a inFIG. 3 . - Similarly, the second opening area of the
second contact hole 20 b denotes an area of a region surrounded by a wall surface of thesecond contact hole 20 b among the surfaces parallel to the first face P1. The second opening area of thesecond contact hole 20 b is, for example, the area of a square illustrated thesecond contact hole 20 b inFIG. 3 . - The
gate electrode pad 32 and the firstpolycrystalline silicon layer 41 are electrically connected via thefirst contact hole 20 a. For example, since thegate electrode pad 32 entering thefirst contact hole 20 a is in contact with the firstpolycrystalline silicon layer 41 at the bottom of thefirst contact hole 20 a, thegate electrode pad 32 and the firstpolycrystalline silicon layer 41 are electrically connected. - The
gate wiring layer 34 and the firstpolycrystalline silicon layer 41 are electrically connected via thesecond contact hole 20 b. For example, since thegate wiring layer 34 entering thesecond contact hole 20 b is in contact with the firstpolycrystalline silicon layer 41 at the bottom of thesecond contact hole 20 b, thegate wiring layer 34 and the firstpolycrystalline silicon layer 41 are electrically connected. - A distance (d in
FIG. 3 ) between thefirst contact hole 20 a and thesecond contact hole 20 b is, for example, 100 μm or more and 300 μm or less. - Next, functions and effects of the semiconductor device according to the first embodiment will be described.
- In a power module in which a plurality of transistor chips are mounted on a substrate, a gate resistance component may be connected to the gate electrode pad of each transistor chip. By connecting the gate resistance component, for example, suppression of resonance between the transistor chips and uniform current in the power module are implemented.
- In a case where the gate resistance component is connected outside the transistor chip, problems such as an increase in size of the power module and a loss of the degree of freedom in arrangement of the transistor chips in the power module occur. For this reason, in some cases, the gate resistor may be embedded in the transistor chip.
- However, the temperature rises due to the heat generated by the embedded gate resistor, and thus, there is a concern that a fluctuation in characteristics of the transistor occurs or the transistor is destructed.
- For example, the resistance value of the gate resistor changes by the temperature rise due to the heat generation of the gate resistor, and thus, the fluctuation in characteristics of the transistor occurs. In addition, for example, by the temperature rise due to the heat generation of the gate resistor, the gate resistor is melted and cut, and thus, the transistor is destructed.
- In the
MOSFET 100 according to the first embodiment, the first opening area of thefirst contact hole 20 a for connecting thegate electrode pad 32 and the firstpolycrystalline silicon layer 41 is larger than the second opening area of thesecond contact hole 20 b for connecting thegate wiring layer 34 and the firstpolycrystalline silicon layer 41. - Since the first opening area of the
first contact hole 20 a is large, the heat generated in the firstpolycrystalline silicon layer 41 easily flows to thegate electrode pad 32. - The
gate electrode pad 32 has a larger area than thegate wiring layer 34. For this reason, thegate electrode pad 32 has a higher heat dissipation efficiency than thegate wiring layer 34. In addition, in a state where theMOSFET 100 is mounted on the power module, for example, a bonding wire is connected to thegate electrode pad 32. For this reason, thegate electrode pad 32 can be expected to dissipate heat through the bonding wire. In addition, since it is necessary to perform bonding on thegate electrode pad 32, a protective film is not formed. Therefore, the heat dissipation efficiency is higher than that of thegate wiring layer 34 on which the protective film is formed. - The heat generated in the first
polycrystalline silicon layer 41 more easily flows to thegate electrode pad 32 than thegate wiring layer 34, so that the temperature rise of the firstpolycrystalline silicon layer 41 is suppressed. Therefore, the fluctuation in characteristics and destruction of theMOSFET 100 are suppressed. - From the viewpoint of suppressing the temperature rise of the first
polycrystalline silicon layer 41, the first opening area is preferably twice or more, more preferably four times or more of the second opening area. - As described above, according to the first embodiment, it is possible to provide a semiconductor device in which the temperature rise of the embedded gate resistor is suppressed.
- A semiconductor device according to a second embodiment is different from the semiconductor device according to the first embodiment in that the number of at least one first opening is larger than the number of at least one second opening. Hereinafter, some descriptions of the contents overlapping with the first embodiment will be omitted.
- The semiconductor device according to the second embodiment is a
MOSFET 200. -
FIG. 5 is a schematic top view of a portion of the semiconductor device according to the second embodiment.FIG. 5 is a diagram corresponding toFIG. 3 of the first embodiment. - As illustrated in
FIG. 5 , in theMOSFET 200 according to the second embodiment, the number of first contact holes 20 a is larger than the number of second contact holes 20 b. The number of first contact holes 20 a corresponding to one firstpolycrystalline silicon layer 41 is four, and the number of second contact holes 20 b is one. - When a plurality of the first contact holes 20 a are provided, a first opening area of the first contact holes 20 a is the sum of the opening areas of the individual first contact holes 20 a. Similarly, when a plurality of the second contact holes 20 b are provided, a second opening area of the second contact holes 20 b is the sum of the opening areas of the individual second contact holes 20 b.
- In the case of
FIG. 5 , the first opening area of thefirst contact hole 20 a is four times of the second opening area of thesecond contact hole 20 b. - As described above, according to the second embodiment, similarly to the first embodiment, it is possible to provide the semiconductor device in which a temperature rise of an embedded gate resistor is suppressed.
- A semiconductor device according to a third embodiment is different from the semiconductor device according to the first embodiment in that the semiconductor device according to the third embodiment further includes a second polycrystalline silicon layer provided on a side of a first face of a semiconductor layer, the second polycrystalline silicon layer electrically connected to an electrode pad, the second polycrystalline silicon layer electrically separated from a wiring layer, and the second polycrystalline silicon layer extending in a first direction. Hereinafter, some descriptions of the contents overlapping with the first embodiment will be omitted.
- The semiconductor device according to the third embodiment is a
MOSFET 300. -
FIG. 6 is a schematic top view of a portion of the semiconductor device according to the third embodiment. -
FIG. 6 is a diagram corresponding toFIG. 3 of the first embodiment. -
FIG. 7 is a schematic cross-sectional view of a portion of the semiconductor device according to the third embodiment.FIG. 7 is a cross-sectional view taken along line CC′ ofFIG. 6 . - As illustrated in
FIGS. 6 and 7 , theMOSFET 300 according to the third embodiment includes a secondpolycrystalline silicon layer 42 in addition to a firstpolycrystalline silicon layer 41. The secondpolycrystalline silicon layer 42 is provided on the side of a first face P1 of asilicon carbide layer 10. The secondpolycrystalline silicon layer 42 extends in the first direction. - The second
polycrystalline silicon layer 42 is electrically connected to agate electrode pad 32. The secondpolycrystalline silicon layer 42 is electrically separated from agate wiring layer 34. - A contact hole for electrically connecting the
gate wiring layer 34 and the secondpolycrystalline silicon layer 42 is not provided to aninterlayer insulating layer 20. - Since the
MOSFET 300 according to the third embodiment includes the secondpolycrystalline silicon layer 42 which is electrically separated from agate wiring layer 34, it is possible to set a gate resistor to have a higher resistance value than that of theMOSFET 100 according to the first embodiment. - As described above, according to the third embodiment, similarly to the first embodiment, it is possible to provide the semiconductor device in which a temperature rise of the embedded gate resistor is suppressed.
- A semiconductor device according to a fourth embodiment includes: a semiconductor layer having a first face and a second face facing the first face; a first electrode being provided on a side of the first face of the semiconductor layer; a second electrode being provided on a side of the second face of the semiconductor layer; a gate electrode being provided on the side of the first face of the semiconductor layer; an electrode pad being provided on the side of the first face of the semiconductor layer; a wiring layer being provided on the side of the first face of the semiconductor layer and being electrically connected to the gate electrode; a first polycrystalline silicon layer being provided on the side of the first face of the semiconductor layer, being electrically connected to the electrode pad and the wiring layer, extending in a first direction parallel to the first face, and including a first p-type region and a first n-type region; a second polycrystalline silicon layer being provided on the side of the first face of the semiconductor layer, being electrically connected to the electrode pad and the wiring layer, extending in the first direction, including a second n-type region and a second p-type region, and being separated from the first polycrystalline silicon layer; and an insulating layer being provided between the first polycrystalline silicon layer and the electrode pad, between the second polycrystalline silicon layer and the electrode pad, between the first polycrystalline silicon layer and the wiring layer, between the second polycrystalline silicon layer and the wiring layer, and including at least one first opening, at least one second opening, at least one third opening, and at least one fourth opening, wherein the electrode pad and the first p-type region are electrically connected via the at least one first opening, wherein the wiring layer and the first n-type region are electrically connected via the at least one second opening, wherein the electrode pad and the second n-type region are electrically connected via the at least one third opening, wherein the wiring layer and the second p-type region are electrically connected via the at least one fourth opening, wherein a first distance between a first junction plane of the first p-type region and the first n-type region and the at least one first opening is smaller than a second distance between the first junction plane and the at least one second opening, and wherein a third distance between a second junction plane of the second n-type region and the second p-type region and the at least one third opening is smaller than a fourth distance between the second junction plane and the at least one fourth opening. Hereinafter, in some cases, some descriptions of the contents overlapping with the first embodiment will be omitted.
- The semiconductor device according to the fourth embodiment is a MOSFET 400. The MOSFET 400 has a transistor structure similar to the structure illustrated in
FIG. 1 of the first embodiment. -
FIG. 8 is a schematic top view of a portion of the semiconductor device according to the fourth embodiment.FIG. 8 is a diagram corresponding toFIG. 3 of the first embodiment. -
FIG. 9 is a schematic cross-sectional view of a portion of the semiconductor device according to the fourth embodiment.FIG. 9 is a cross-sectional view taken along line DD′ ofFIG. 8 . -
FIG. 10 is a schematic cross-sectional view of a portion of the semiconductor device according to the fourth embodiment.FIG. 10 is a cross-sectional view taken along line EE′ ofFIG. 8 . - As illustrated in
FIGS. 8, 9 and 10 , the MOSFET 400 includes a silicon carbide layer 10 (semiconductor layer), a source electrode 12 (first electrode), an interlayer insulating layer 20 (insulating layer), a gate electrode pad 32 (electrode pad), a gate wiring layer 34 (wiring layer), a plurality of first polycrystalline silicon layers 51, a plurality of second polycrystalline silicon layers 52, and afield insulating layer 44. The interlayer insulatinglayer 20 includes afirst contact hole 20 a (first opening), asecond contact hole 20 b (second opening), athird contact hole 20 c (third opening), and afourth contact hole 20 d (fourth opening). - The
field insulating layer 44 is provided on thesilicon carbide layer 10. Thefield insulating layer 44 is, for example, a silicon oxide film. - The first
polycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52 are provided on thesilicon carbide layer 10. The firstpolycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52 are provided on thefield insulating layer 44. - The first
polycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52 are electrically connected to thegate electrode pad 32 and thegate wiring layer 34. Thegate electrode pad 32, the firstpolycrystalline silicon layer 51, thegate wiring layer 34, and thegate electrode 16 are connected in series. Thegate electrode pad 32, the secondpolycrystalline silicon layer 52, thegate wiring layer 34, and thegate electrode 16 are connected in series. The firstpolycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52 function as gate resistors embedded in the MOSFET 400. - The first
polycrystalline silicon layer 51 extends in the first direction. A length of the firstpolycrystalline silicon layer 51 in the first direction is, for example, 200 μm or more and 500 μm or less. A width of the firstpolycrystalline silicon layer 51 in the second direction is, for example, 20 μm or more and 50 μm or less. - The first
polycrystalline silicon layer 51 includes a first p-type region 51 a and a first n-type region 51 b. The firstpolycrystalline silicon layer 51 functions as a gate resistor with a pn diode. - The first p-
type region 51 a contains p-type impurities. The p-type impurity is, for example, boron (B). - The first n-type region 51 b contains n-type impurities. The n-type impurity is, for example, phosphorus (P) or arsenic (As).
- The second
polycrystalline silicon layer 52 extends in the first direction. The secondpolycrystalline silicon layer 52 is separated from the firstpolycrystalline silicon layer 51. A length of the secondpolycrystalline silicon layer 52 in the first direction is, for example, 200 μm or more and 500 μm or less. A width of the secondpolycrystalline silicon layer 52 in the second direction is, for example, 20 μm or more and 50 μm or less. - The second
polycrystalline silicon layer 52 includes a second n-type region 52 a and a second p-type region 52 b. The secondpolycrystalline silicon layer 52 functions as a gate resistor with a pn diode. - The second n-
type region 52 a contains n-type impurities. The n-type impurity is, for example, phosphorus (P) or arsenic (As). - The second p-
type region 52 b contains p-type impurities. The p-type impurity is, for example, boron (B). - The interlayer insulating
layer 20 is provided between the firstpolycrystalline silicon layer 51 and thegate electrode pad 32 and between the secondpolycrystalline silicon layer 52 and thegate electrode pad 32. The interlayer insulatinglayer 20 is provided between the firstpolycrystalline silicon layer 51 and thegate wiring layer 34 and between the secondpolycrystalline silicon layer 52 and thegate wiring layer 34. - The interlayer insulating
layer 20 has afirst contact hole 20 a, asecond contact hole 20 b, athird contact hole 20 c, and afourth contact hole 20 d. Thefirst contact hole 20 a, thesecond contact hole 20 b, thethird contact hole 20 c, and thefourth contact hole 20 d are hole patterns provided in theinterlayer insulating layer 20. - The
gate electrode pad 32 and the first p-type region 51 a are electrically connected via thefirst contact hole 20 a. For example, since thegate electrode pad 32 entering thefirst contact hole 20 a is in contact with the first p-type region 51 a at the bottom of thefirst contact hole 20 a, thegate electrode pad 32 and the first p-type region 51 a are electrically connected. - The
gate wiring layer 34 and the first n-type region 51 b are electrically connected via thesecond contact hole 20 b. For example, since thegate wiring layer 34 entering thesecond contact hole 20 b is in contact with the first n-type region 51 b at the bottom of thesecond contact hole 20 b, thegate wiring layer 34 and the first n-type region 51 b are electrically connected. - A distance between the
first contact hole 20 a and thesecond contact hole 20 b is, for example, 100 μm or more and 300 μm or less. - A boundary between the first p-
type region 51 a and the first n-type region 51 b is afirst junction plane 51 x. Thefirst junction plane 51 x is a pn junction. - A first distance (d1 in
FIG. 8 ) between thefirst junction plane 51 x and thefirst contact hole 20 a is smaller than a second distance (d2 inFIG. 8 ) between thefirst junction plane 51 x and thesecond contact hole 20 b. The first distance d1 is, for example, one-half or less of the second distance d2. - The
gate electrode pad 32 and the second n-type region 52 a are electrically connected via thethird contact hole 20 c. For example, since thegate electrode pad 32 entering thethird contact hole 20 c is in contact with the second n-type region 52 a at the bottom of thethird contact hole 20 c, thegate electrode pad 32 and the second n-type region 52 a are electrically connected. - The
gate wiring layer 34 and the second p-type region 52 b are electrically connected via thefourth contact hole 20 d. For example, since thegate wiring layer 34 entering thefourth contact hole 20 d is in contact with the second p-type region 52 b at the bottom of thefourth contact hole 20 d, thegate wiring layer 34 and the second p-type region 52 b are electrically connected. - A distance between the
third contact hole 20 c and thefourth contact hole 20 d is, for example, 100 μm or more and 300 μm or less. - A boundary between the second n-
type region 52 a and the second p-type region 52 b is asecond junction plane 52 x. Thesecond junction plane 52 x is a pn junction. - A third distance (d3 in
FIG. 8 ) between thesecond junction plane 52 x and thethird contact hole 20 c is smaller than a fourth distance (d4 inFIG. 8 ) between thesecond junction plane 52 x and thefourth contact hole 20 d. The third distance d3 is, for example, one-half or less of the fourth distance d4. - Next, functions and effects of the semiconductor device according to the first embodiment will be described.
-
FIG. 11 is an explanatory diagram of functions and effects of the semiconductor device according to the fourth embodiment.FIG. 11 illustrates an equivalent circuit diagram including the gate resistors of the MOSFET 400. - In the MOSFET 400, different resistance values of the gate resistor can be applied at the time of the turn-on operation of the transistor and at the time of the turn-off operation of the transistor. In other words, an optimum resistance value of the gate resistor can be applied at the time of the turn-on operation of the transistor and at the time of the turn-off operation of the transistor.
- For example, at the time of the turn-on operation in which the gate voltage Vg applied to the
gate electrode pad 32 becomes a positive voltage with respect to thegate electrode 16, only the firstpolycrystalline silicon layer 51 functions as a gate resistor. - On the other hand, for example, at the time of the turn-off operation in which the gate voltage Vg applied to the
gate electrode pad 32 becomes a negative voltage with respect to thegate electrode 16, only the secondpolycrystalline silicon layer 52 functions as a gate resistor. - As illustrated in
FIG. 8 , in the fourth embodiment, the number of first polycrystalline silicon layers 51 connected in parallel is two, and the number of second polycrystalline silicon layers 52 connected in parallel is four. For this reason, in a case where the resistance value of each of the firstpolycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52 is the same, the resistance value at the time of the turn-on operation of the transistor is larger than the resistance value at the time of the turn-off operation. For example, by increasing the resistance value at the time of the turn-on operation of the transistor, the resonance between the transistor chips can be suppressed. For example, a turn-off loss can be reduced by decreasing the resistance value at the time of the turn-off operation of the transistor. - In the MOSFET 400, the temperature of the first
polycrystalline silicon layer 51 or the secondpolycrystalline silicon layer 52 rises due to the heat generated by the diode, and thus, there is a concern that a fluctuation in characteristics of the transistor occurs or the transistor is destructed. - In the MOSFET 400 according to the fourth embodiment, the first distance (d1 in
FIG. 8 ) between thefirst junction plane 51 x and thefirst contact hole 20 a is smaller than the second distance (d2 inFIG. 8 ) between thefirst junction plane 51 x and thesecond contact hole 20 b. For this reason, thefirst contact hole 20 a connected to thegate electrode pad 32 is provided at a location close to the pn junction of the diode. - Since the pn junction of the diode is close to the
first contact hole 20 a, the heat generated by the diode of the firstpolycrystalline silicon layer 51 easily flows to thegate electrode pad 32. - In addition, in the MOSFET 400 according to the fourth embodiment, the third distance (d3 in
FIG. 8 ) between thesecond junction plane 52 x and thethird contact hole 20 c is smaller than the fourth distance (d4 inFIG. 8 ) between thesecond junction plane 52 x and thefourth contact hole 20 d. For this reason, thethird contact hole 20 c connected to thegate electrode pad 32 is provided at a location close to the pn junction of the diode. - Since the pn junction of the diode is close to the
third contact hole 20 c, the heat generated by the diode of the secondpolycrystalline silicon layer 52 easily flows to thegate electrode pad 32. - The
gate electrode pad 32 has a larger area than thegate wiring layer 34. For this reason, thegate electrode pad 32 has a higher heat dissipation efficiency than thegate wiring layer 34. In addition, in a state where the MOSFET 400 is mounted on the power module, for example, a bonding wire is connected to thegate electrode pad 32. Thegate electrode pad 32 can be expected to dissipate heat through the bonding wire. In addition, a protective film is not formed on thegate electrode pad 32 for performing bonding. Therefore, the heat dissipation efficiency is higher than that of thegate wiring layer 34 on which the protective film is formed. - The heat generated by the diodes of the first
polycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52 easily flows to thegate electrode pad 32, so that a temperature rise of the firstpolycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52 is suppressed. Therefore, the fluctuation in characteristics and the of the MOSFET 400 are suppressed. - From the viewpoint of suppressing the temperature rise of the first
polycrystalline silicon layer 51, the first distance d1 is preferably one-half or less of the second distance d2, more preferably one-fourth or less of the second distance d2. In addition, from the viewpoint of suppressing the temperature rise of the secondpolycrystalline silicon layer 52, the third distance d3 is preferably one-half or less of the fourth distance d4, more preferably one-fourth or less of the fourth distance d4. - In addition, in
FIG. 8 , the case of changing the resistance value at the time of the turn-on operation of the transistor and the resistance value at the time of the turn-off operation of the transistor by changing the number of the first polycrystalline silicon layers 51 and the number of the second polycrystalline silicon layers 52 connected in parallel has been described as an example. However, for example, the resistance value at the time of the turn-on operation of the transistor and the resistance value at the time of the turn-off operation of the transistor may be allowed to be changed by changing the resistance value of each of the firstpolycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52. - In addition, the case where the resistance value at the time of the turn-on operation of the transistor is allowed to be larger than the resistance value at the time of the turn-off operation is described as an example, but the resistance value at the time of the turn-on operation of the transistor may be allowed to be smaller than the resistance value at the time of the turn-off operation.
- As described above, according to the fourth embodiment, it is possible to provide a semiconductor device in which the temperature rise of the embedded gate resistor is suppressed.
- A semiconductor device according to a fifth embodiment is different from the semiconductor device according to the fourth embodiment in that a first opening area of at least one first opening is larger than a second opening area of at least one second opening, and a third opening area of at least one third opening is larger than a fourth opening area of at least one fourth opening. Hereinafter, in some cases, some descriptions of the contents overlapping with the fourth embodiment will be omitted.
- The semiconductor device according to the fifth embodiment is a
MOSFET 500. -
FIG. 12 is a schematic top view of a portion of the semiconductor device according to the fifth embodiment.FIG. 12 is a diagram corresponding toFIG. 8 of the fourth embodiment. - As illustrated in
FIG. 12 , in theMOSFET 500 according to the fifth embodiment, a first opening area of afirst contact hole 20 a is larger than a second opening area of asecond contact hole 20 b. Since the first opening area of thefirst contact hole 20 a is large, the heat generated in a firstpolycrystalline silicon layer 51 easily flows to agate electrode pad 32. - In addition, a third opening area of a
third contact hole 20 c is larger than a fourth opening area of afourth contact hole 20 d. Since the third opening area of thethird contact hole 20 c is large, the heat generated in a secondpolycrystalline silicon layer 52 easily flows to agate electrode pad 32. - Therefore, the
MOSFET 500 according to the fifth embodiment can further suppress a temperature rise of the firstpolycrystalline silicon layer 51 and the secondpolycrystalline silicon layer 52 as compared with the MOSFET 400 according to the fourth embodiment. - As described above, according to the fifth embodiment, it is possible to provide the semiconductor device in which a temperature rise of an embedded gate resistor is suppressed.
- As described above, in the first to fifth embodiments, the n-channel MOSFETs are described as examples, but the embodiments can also be applied to p-channel MOSFETs.
- In addition, in the first to fifth embodiments, the MOSFETs having a planar gate structure in which a gate electrode is provided on a first face of a semiconductor layer are described as examples, but the embodiments can also be applied to MOSFETs having a trench gate structure in which the gate electrode is provided in a trench formed in the semiconductor layer.
- In addition, the embodiments can also be applied to an insulated gate bipolar transistor (IGBT).
- In addition, in the first to fifth embodiments, the case where silicon carbide is used for the semiconductor layer is described as an example, but the semiconductor layer may be another semiconductor such as silicon.
- While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the semiconductor devices described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the devices and methods described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Claims (12)
1. A semiconductor device comprising:
a semiconductor layer having a first face and a second face facing the first face;
a first electrode provided on a side of the first face of the semiconductor layer;
a second electrode provided on a side of the second face of the semiconductor layer;
a gate electrode provided on the side of the first face of the semiconductor layer;
an electrode pad being provided on the side of the first face of the semiconductor layer;
a wiring layer provided on the side of the first face of the semiconductor layer and electrically connected to the gate electrode;
a first polycrystalline silicon layer provided on the side of the first face of the semiconductor layer, the first polycrystalline silicon layer electrically connected to the electrode pad and the wiring layer, and the first polycrystalline silicon layer extending in a first direction parallel to the first face; and
an insulating layer provided between the first polycrystalline silicon layer and the electrode pad, the insulating layer provided between the first polycrystalline silicon layer and the wiring layer, and the insulating layer having at least one first opening and at least one second opening,
wherein the electrode pad and the first polycrystalline silicon layer are electrically connected via an inside of the at least one first opening,
the wiring layer and the first polycrystalline silicon layer are electrically connected via an inside of the at least one second opening, and
a first opening area of the at least one first opening is larger than a second opening area of the at least one second opening.
2. The semiconductor device according to claim 1 , wherein a length of the first polycrystalline silicon layer in the first direction is 200 μm or more, and a width of the first polycrystalline silicon layer in a second direction parallel to the first face and perpendicular to the first direction is 50 μm or less.
3. The semiconductor device according to claim 1 , wherein the first opening area is twice or more the second opening area.
4. The semiconductor device according to claim 1 , wherein a number of the at least one first opening is larger than a number of the at least one second opening.
5. The semiconductor device according to claim 1 , wherein the electrode pad is in contact with the first polycrystalline silicon layer, and the wiring layer is in contact with the first polycrystalline silicon layer.
6. The semiconductor device according to claim 1 , further comprising a second polycrystalline silicon layer provided on the side of the first face of the semiconductor layer, the second polycrystalline silicon layer electrically connected to the electrode pad, the second polycrystalline silicon layer electrically separated from the wiring layer, and the second polycrystalline silicon layer extending in the first direction.
7. The semiconductor device according to claim 1 , wherein the first polycrystalline silicon layer contains p-type impurities or n-type impurities.
8. The semiconductor device according to claim 1 , wherein the semiconductor layer is a silicon carbide layer.
9. A semiconductor device comprising:
a semiconductor layer having a first face and a second face facing the first face;
a first electrode provided on a side of the first face of the semiconductor layer;
a second electrode provided on a side of the second face of the semiconductor layer;
a gate electrode provided on the side of the first face of the semiconductor layer;
an electrode pad provided on the side of the first face of the semiconductor layer;
a wiring layer provided on the side of the first face of the semiconductor layer and electrically connected to the gate electrode;
a first polycrystalline silicon layer provided on the side of the first face of the semiconductor layer, the first polycrystalline silicon layer electrically connected to the electrode pad and the wiring layer, the first polycrystalline silicon layer extending in a first direction parallel to the first face, and the first polycrystalline silicon layer including a first p-type region and a first n-type region;
a second polycrystalline silicon layer provided on the side of the first face of the semiconductor layer, the second polycrystalline silicon layer electrically connected to the electrode pad and the wiring layer, the second polycrystalline silicon layer extending in the first direction, the second polycrystalline silicon layer including a second n-type region and a second p-type region, and the second polycrystalline silicon layer separated from the first polycrystalline silicon layer; and
an insulating layer provided between the first polycrystalline silicon layer and the electrode pad, the insulating layer provided between the second polycrystalline silicon layer and the electrode pad, the insulating layer provided between the first polycrystalline silicon layer and the wiring layer, the insulating layer provided between the second polycrystalline silicon layer and the wiring layer, and the insulating layer including at least one first opening, the insulating layer including at least one second opening, the insulating layer including at least one third opening, and the insulating layer including at least one fourth opening,
wherein the electrode pad and the first p-type region are electrically connected via the at least one first opening,
the wiring layer and the first n-type region are electrically connected via the at least one second opening,
the electrode pad and the second n-type region are electrically connected via the at least one third opening,
the wiring layer and the second p-type region are electrically connected via the at least one fourth opening,
a first distance between a first junction plane of the first p-type region and the first n-type region and the at least one first opening is smaller than a second distance between the first junction plane and the at least one second opening, and
a third distance between a second junction plane of the second n-type region and the second p-type region and the at least one third opening is smaller than a fourth distance between the second junction plane and the at least one fourth opening.
10. The semiconductor device according to claim 9 ,
wherein a first opening area of the at least one first opening is larger than a second opening area of the at least one second opening, and
a third opening area of the at least one third opening is larger than a fourth opening area of the at least one fourth opening.
11. The semiconductor device according to claim 9 , wherein the first distance is one-half or less of the second distance, and the third distance is one-half or less of the fourth distance.
12. The semiconductor device according to claim 9 , wherein the semiconductor layer is a silicon carbide layer.
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