WO2016009736A1 - スイッチング素子 - Google Patents
スイッチング素子 Download PDFInfo
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- WO2016009736A1 WO2016009736A1 PCT/JP2015/066113 JP2015066113W WO2016009736A1 WO 2016009736 A1 WO2016009736 A1 WO 2016009736A1 JP 2015066113 W JP2015066113 W JP 2015066113W WO 2016009736 A1 WO2016009736 A1 WO 2016009736A1
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- 239000004065 semiconductor Substances 0.000 claims abstract description 39
- 239000000758 substrate Substances 0.000 claims abstract description 37
- 230000015556 catabolic process Effects 0.000 abstract description 8
- 239000010410 layer Substances 0.000 description 55
- 210000000746 body region Anatomy 0.000 description 40
- 239000012535 impurity Substances 0.000 description 26
- 230000005684 electric field Effects 0.000 description 12
- 238000009792 diffusion process Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 238000009826 distribution Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 2
- 238000002513 implantation Methods 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
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- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/7801—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
- H01L29/7802—Vertical DMOS transistors, i.e. VDMOS transistors
- H01L29/7813—Vertical DMOS transistors, i.e. VDMOS transistors with trench gate electrode, e.g. UMOS transistors
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- H01L29/0619—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 for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse biased devices by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE] with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
- H01L29/0623—Buried supplementary region, e.g. buried guard ring
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- H01L29/1095—Body region, i.e. base region, of DMOS transistors or IGBTs
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- H01L29/42312—Gate electrodes for field effect devices
- H01L29/42316—Gate electrodes for field effect devices for field-effect transistors
- H01L29/4232—Gate electrodes for field effect devices for field-effect transistors with insulated gate
- H01L29/42356—Disposition, e.g. buried gate electrode
- H01L29/4236—Disposition, e.g. buried gate electrode within a trench, e.g. trench gate electrode, groove gate electrode
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- H01L29/42312—Gate electrodes for field effect devices
- H01L29/42316—Gate electrodes for field effect devices for field-effect transistors
- H01L29/4232—Gate electrodes for field effect devices for field-effect transistors with insulated gate
- H01L29/42364—Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the insulating layer, e.g. thickness or uniformity
- H01L29/42368—Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the insulating layer, e.g. thickness or uniformity the thickness being non-uniform
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- H01L29/66068—Multistep manufacturing processes of devices having a semiconductor body comprising crystalline silicon carbide the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
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- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66674—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
- H01L29/66712—Vertical DMOS transistors, i.e. VDMOS transistors
- H01L29/66734—Vertical DMOS transistors, i.e. VDMOS transistors with a step of recessing the gate electrode, e.g. to form a trench gate electrode
Definitions
- the technology disclosed in this specification relates to a switching element.
- Patent Document 1 discloses a MOSFET having a trench-type gate electrode.
- a bottom insulating layer is formed below the gate electrode in the trench.
- a p-type floating region is formed at a position in contact with the lower end of the bottom insulating layer.
- the floating region is separated from the p-type body region by an n-type drift region.
- a depletion layer extends from both the body region and the floating region to the drift region between the body region and the floating region.
- the drift region between the body region and the floating region is depleted, and the electric field applied to the gate insulating film is relaxed. Thereby, the high breakdown voltage of the MOSFET is realized.
- the floating region described above is formed by implanting p-type impurities into the bottom surface of the trench and then diffusing the p-type impurities. If the diffusion distance of the p-type impurity at this time is long, a floating region extending widely to the upper side of the lower end portion of the bottom insulating layer (that is, the lower end portion of the trench) can be formed as in Patent Document 1. However, depending on the material of the semiconductor substrate and the material of the p-type impurity, the p-type impurity is difficult to diffuse in the semiconductor substrate, and the diffusion distance of the p-type impurity may be shortened.
- the present specification provides a technique for realizing high breakdown voltage characteristics even in the case where the upper portion is short in a switching element having a p-type region at the lower end of the trench.
- the technology disclosed in this specification includes a semiconductor substrate having a front surface and a back surface, in which a trench is formed on the front surface, a bottom insulating layer disposed at a bottom in the trench, and more than the bottom insulating layer.
- a gate insulating film covering a side surface of the trench on the front surface side, and disposed in the trench on the surface side of the bottom insulating layer from the semiconductor substrate by the bottom insulating layer and the gate insulating film. It has an insulated gate electrode.
- the semiconductor substrate includes a first n-type region in contact with the gate insulating film, a first p-type region in contact with the gate insulating film on the back surface side of the first n-type region, and an end portion on the back surface side of the bottom insulating layer.
- a second p-type region that is in contact with the first p-type region, and is separated from the first n-type region by the first p-type region, and the gate insulating film and the bottom insulating layer A second n-type region in contact with the layer, extending to a position closer to the back side than the second p-type region, and separating the second p-type region from the first p-type region; A distance A from an end of the first p-type region on the back surface side to an end of the second p-type region on the surface side; and from the end of the bottom insulating layer on the back surface side of the second p-type region.
- the distance B to the end on the back surface side satisfies the relationship of A ⁇ 4B.
- the distance C from the end portion on the front surface side of the second p-type region to the end portion on the back surface side of the bottom insulating layer is from the end portion on the back surface side of the first p-type region to the gate electrode. It is smaller than the distance D to the end on the back side.
- the distances A, B, C, and D mean distances measured along the thickness direction of the semiconductor substrate.
- the depletion layer extends from the first p-type region and the second p-type region to the second n-type region between them (that is, the second n-type region at a distance A), so that it is applied to the gate insulating film. Suppresses the electric field.
- the distance C is smaller than the distance D.
- the distance B is set long (that is, A ⁇ 4B is satisfied)
- the depletion layer can be extended widely from the second p-type region to the first p-type region side. Since the distance D can be adjusted by the depth of impurity implantation into the bottom surface of the trench, the distance D can be increased even when it is difficult for the p-type impurity to diffuse in the semiconductor substrate. When the relationship of A ⁇ 4B is satisfied, high breakdown voltage characteristics can be obtained. Therefore, this switching element has high withstand voltage characteristics.
- the longitudinal cross-sectional view of MOSFET10. The graph which shows the electric field distribution in the area
- the MOSFET 10 includes a semiconductor substrate 12, a front electrode 14, and a back electrode 16.
- the semiconductor substrate 12 is made of SiC.
- the semiconductor substrate 12 has a front surface (front surface) 12a and a back surface 12b located on the back side of the front surface 12a.
- the surface electrode 14 is formed on the surface 12a.
- the back electrode 16 is formed on the back surface 12b.
- a plurality of trenches 18 are formed on the surface 12 a of the semiconductor substrate 12. Each trench 18 extends in a direction perpendicular to the surface 12a (the thickness direction of the semiconductor substrate 12). Each trench 18 extends long in a direction perpendicular to the paper surface of FIG. Inside each trench 18, a bottom insulating layer 20, a gate insulating film 22 and a gate electrode 24 are formed.
- the bottom insulating layer 20 is disposed at the bottom of the trench 18.
- the bottom insulating layer 20 is embedded in the bottom of the trench 18 without a gap.
- the gate insulating film 22 covers the side surface of the trench 18 on the upper side (surface 12a side) than the bottom insulating layer 20.
- the gate electrode 24 is disposed in the trench 18 above the bottom insulating layer 20. That is, the bottom insulating layer 20 is disposed between the gate electrode 24 and the bottom surface of the trench 18. A gate insulating film 22 is disposed between the gate electrode 24 and the side surface of the trench 18. The gate electrode 24 is insulated from the semiconductor substrate 12 by the bottom insulating layer 20 and the gate insulating film 22. The upper surface of the gate electrode 24 is covered with an interlayer insulating film 26. The gate electrode 24 is insulated from the surface electrode 14 by the interlayer insulating film 26.
- a source region 30, a body region 32, a bottom p-type region 34, a drift region 36, and a drain region 38 are formed.
- the source region 30 is an n-type region.
- the source region 30 is exposed on the surface 12 a of the semiconductor substrate 12.
- the source region 30 is electrically connected to the surface electrode 14. More specifically, the source region 30 is ohmically connected to the surface electrode 14. Further, the source region 30 is in contact with the gate insulating film 22 in the vicinity of the surface 12 a of the semiconductor substrate 12.
- the body region 32 is a p-type region.
- the body region 32 has a high concentration body region 32a and a low concentration body region 32b.
- the high concentration body region 32 a is formed between the two source regions 30.
- the high concentration body region 32 a is exposed on the surface 12 a of the semiconductor substrate 12.
- the high concentration body region 32a is electrically connected to the surface electrode. More specifically, the high concentration body region 32 a is ohmically connected to the surface electrode 14.
- the p-type impurity concentration of the low-concentration body region 32b is lower than the p-type impurity concentration of the high-concentration body region 32a.
- the low concentration body region 32b is in contact with the source region 30 and the high concentration body region 32a.
- the low-concentration body region 32b is in contact with the gate insulating film 22 on the lower side (back surface 12b side) of the source region 30.
- the lower end of the low concentration body region 32 b (that is, the position of the boundary surface between the low concentration body region 32 b and the drift region 36) is located above the lower end of each gate electrode 24.
- the drift region 36 is an n-type region.
- the drift region 36 is formed below the low concentration body region 32b.
- the drift region 36 is in contact with the low-concentration body region 32b.
- the drift region 36 is separated from the source region 30 by the low concentration body region 32b.
- the drift region 36 is in contact with the gate insulating film 22 and the bottom insulating layer 20 below the low-concentration body region 32b.
- the drift region 36 extends below the bottom p-type region 34.
- the bottom p-type region 34 is a p-type region and is formed in contact with the bottom surface of each trench 18. That is, the bottom p-type region 34 is in contact with the lower end of the bottom insulating layer 20. The upper end of the bottom p-type region 34 is located above the lower end of the bottom insulating layer 20. A part of the upper side of the bottom p-type region 34 is in contact with the side surface of the bottom insulating layer 20. The periphery of bottom p-type region 34 is surrounded by drift region 36. Bottom p-type region 34 is separated from low-concentration body region 32 b by drift region 36. The bottom p-type region 34 is separated from other bottom p-type regions 34 by a drift region 36. Bottom p-type region 34 is in contact only with bottom insulating layer 20 and drift region 36. Therefore, the potential of the bottom p-type region 34 is floating.
- the drain region 38 is an n-type region.
- the n-type impurity concentration of the drain region 38 is higher than the n-type impurity concentration of the drift region 36.
- the drain region 38 is formed below the drift region 36.
- the drain region 38 is in contact with the drift region 36.
- the drain region 38 is exposed on the back surface 12 b of the semiconductor substrate 12.
- the drain region 38 is electrically connected to the back electrode 16. More specifically, the drain region 38 is ohmically connected to the back electrode 16.
- a distance A in FIG. 1 is a distance from the lower end of the low-concentration body region 32 b to the upper end of the bottom p-type region 34.
- a distance B in FIG. 1 is a distance from the lower end of the bottom insulating layer 20 to the lower end of the bottom p-type region 34.
- the distances A and B are distances measured along the thickness direction of the semiconductor substrate 12. The distance A is shorter than the distance four times the distance B. That is, the relationship of A ⁇ 4B is satisfied.
- a distance D in FIG. 1 is a distance from the lower end of the low concentration body region 32 b to the lower end of the gate electrode 24.
- the distances C and D are distances measured along the thickness direction of the semiconductor substrate 12. The distance C is smaller than the distance D. That is, the relationship of C ⁇ D is satisfied.
- a voltage at which the back electrode 16 has a high potential is applied between the back electrode 16 and the front electrode 14.
- the voltage applied between the back electrode 16 and the front electrode 14 can be, for example, a voltage of 1200 V or more.
- the MOSFET 10 is turned on, and the voltage between the back electrode 16 and the front electrode 14 is reduced to several volts (for example, 3V). That is, when a potential higher than the threshold is applied to the gate electrode 24, a channel is formed in the low-concentration body region 32b in the range in contact with the gate insulating film 22.
- the source region 30 and the drift region 36 are connected by the channel. Accordingly, electrons flow from the front electrode 14 toward the back electrode 16 via the source region 30, the channel, the drift region 36, and the drain region 38. For this reason, a current flows from the back electrode 16 toward the front electrode 14.
- the channel disappears and the MOSFET 10 is turned off.
- a depletion layer extends from the low concentration body region 32 b into the drift region 36.
- a depletion layer also extends from the bottom p-type region 34 into the drift region 36.
- the drift region 36 is depleted by the depletion layer extending from the low-concentration body region 32 b and the bottom p-type region 34 into the drift region 36.
- the applied voltage (high voltage) between the back electrode 16 and the front electrode 14 is maintained by the depleted drift region 36.
- the drift region 36 between the low-concentration body region 32b and the bottom p-type region 34 (that is, the drift region 36 at the distance A, hereinafter referred to as the interval drift region) is low as shown by the arrow X1 in FIG.
- the entire interval drift region is depleted. It is considered that the electric field applied to the gate insulating film 22 can be effectively relaxed when the gap drift region is depleted.
- the distance C (that is, the thickness of the bottom p-type region 34 protruding above the lower end of the bottom insulating layer 20) is small.
- the distance A becomes long.
- the depletion layer indicated by the arrow X2 is difficult to extend as compared with the case where the distance C is large. For this reason, when the distance C is small, it is disadvantageous when the interval drift region is depleted.
- the distance B also affects the elongation of the depletion layer indicated by the arrow X2.
- the distance C is small, but when the distance B is large, the elongation of the depletion layer indicated by the arrow X2 is promoted.
- the distance C is small, whether or not the entire interval drift region is depleted is considered to be determined by the ratio of the distance A and the distance B. That is, even if the distance A is large, if the distance B is large, it is considered that the entire interval drift region can be depleted.
- FIG. 2 shows the electric field distribution in the region of the straight line Y in FIG. 1 when the MOSFET 10 is off. That is, the distribution of the electric field in the source region 30, the body region 32, the drift region 36, and the bottom p-type region 34 near the trench 18 in the thickness direction of the semiconductor substrate 12 is shown. 2 indicates the depth from the surface 12a of the semiconductor substrate 12 (that is, the position in the thickness direction of the semiconductor substrate 12), and the left side is the surface 12a side.
- the graph in FIG. 2 is calculated by simulation.
- FIG. 2 shows a graph of the electric field distribution in each case where the distance B is constant and the distance A is changed.
- the first peak is formed at a depth of about 1.6 ⁇ m in any graph.
- the position having a depth of about 1.6 ⁇ m is the position of the boundary surface between the low concentration body region 32 b and the drift region 36.
- the second peak P2 is formed at a position deeper than the first peak.
- the position of the second peak P2 is the position of the boundary between the bottom p-type region 34 and the drift region 36 above it. Since the distance A is different for each graph, the position of the second peak P2 is shifted to the deeper side as the distance A is larger.
- the size of the second peak P2 is substantially constant when the distance A is smaller than 4.00B.
- FIG. 3 shows the relationship between the distance A and the electric field at the second peak P2.
- FIG. 3 shows a case where the n-type impurity concentration Nd of the drift region 36 is 1.3 ⁇ 10 16 atoms / cm 3 and a case where it is 1.6 ⁇ 10 16 atoms / cm 3 . .
- the n-type impurity concentration in the drift region 36 is more preferably 1.6 ⁇ 10 16 atoms / cm 3 or less. Further, it is more preferable that A ⁇ 3.4B because the fluctuation range of the second peak P2 becomes smaller.
- the p-type impurity concentration of the bottom p-type region 34 is set to such a concentration that the entire bottom p-type region 34 is not depleted when the MOSFET 10 is turned off. If the p-type impurity concentration of the bottom p-type region 34 is set in this way, the p-type impurity concentration of the bottom p-type region 34 does not affect the extending width of the depletion layer. Therefore, the results of FIGS. 2 and 3 can be obtained regardless of the p-type impurity concentration of the bottom p-type region 34. For example, if the p-type impurity concentration of the bottom p-type region 34 is 1 ⁇ 10 18 atoms / cm 3 or more, the entire bottom p-type region 34 is not depleted.
- the MOSFET 10 of this embodiment since A ⁇ 4B is satisfied, the entire gap drift region can be depleted when the MOSFET 10 is turned off. Therefore, the electric field applied to the gate insulating film 22 is relaxed. For this reason, the MOSFET 10 has high breakdown voltage characteristics.
- the method for manufacturing MOSFET 10 is characterized by the step of forming bottom p-type region 34, and therefore the description of the other steps is omitted.
- the trench 18 is formed in the surface 12a of the n-type semiconductor substrate 12 made of SiC.
- aluminum (Al) is implanted into the bottom surface of the trench 18.
- Al is also implanted into the surface 12 a of the semiconductor substrate 12.
- Al injected into the semiconductor substrate 12 is diffused and activated.
- a bottom p-type region 34 is formed in the vicinity of the bottom surface of the trench 18 as shown in FIG.
- a low concentration body region 32 b is formed in the vicinity of the surface 12 a of the semiconductor substrate 12.
- the diffusion coefficient of Al in SiC is extremely small. Therefore, the distance at which Al implanted into the bottom surface of the trench 18 diffuses during the subsequent heat treatment is short. For this reason, when the bottom p-type region 34 is formed by the above method, the distance C is shortened. If the amount of Al injected into the bottom surface of the trench 18 is increased, the Al diffusion distance becomes slightly longer, so that the distance C can be made slightly longer. However, in this case, the p-type impurity concentration in the low-concentration body region 32b increases, and problems such as an increase in the gate threshold potential of the MOSFET 10 and an increase in leakage current occur. Therefore, in practice, it is difficult to increase the distance C, and the distance C is shorter than the distance D (see FIG. 1).
- the distance B can be controlled by the implantation depth when Al is implanted into the bottom surface of the trench 18. That is, by adjusting the energy at the time of ion implantation, as shown in FIG. 4, Al can be distributed over a wide range from the bottom surface of the trench 18 to a deep position. Thus, if Al is distributed to a deep position by ion implantation, the distance B of the bottom p-type region 34 can be increased even if the Al diffusion distance is short during the subsequent heat treatment. Therefore, the bottom p-type region 34 satisfying A ⁇ 4B can be formed.
- the MOSFET 10 having high breakdown voltage characteristics can be manufactured.
- the bottom p-type region 34 and the low-concentration body region 32b are formed at the same time, but these may be formed in separate steps.
- the potential of the bottom p-type region 34 is floating, but the bottom p-type region 34 may be connected to a predetermined fixed potential.
- the source region of the embodiment is an example of the first n-type region of the claims
- the body region of the embodiment is an example of the first p-type region of the claims
- the bottom p-type region of the embodiment is the first of the claims. It is an example of a 2p type region
- the drift region of the embodiment is an example of a second n type region in the claims.
- MOSFET has been described in the embodiment, the technology disclosed in this specification may be applied to other switching elements such as IGBTs.
- the semiconductor substrate may be made of a SiC-based semiconductor, and the second p-type region may contain Al.
- the material of the semiconductor substrate and the material of the p-type impurity are a combination having a small diffusion coefficient of the p-type impurity, a high breakdown voltage characteristic can be realized by satisfying the relationship of A ⁇ 4B.
- the n-type impurity concentration of the second n-type region may be 1.6 ⁇ 10 16 atoms / cm 3 or less.
- the n-type impurity concentration of the second n-type region may be 1.3 ⁇ 10 16 atoms / cm 3 or more.
- a surface electrode is formed on the surface of the semiconductor substrate, and the first n-type region and the first p-type region are connected to the surface electrode.
- a back electrode is formed on the back surface of the semiconductor substrate, and the second n-type region is connected to the back electrode.
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Abstract
Description
本出願は、2014年7月18日に出願された日本特許出願特願2014-147459の関連出願であり、この日本特許出願に基づく優先権を主張するものであり、この日本特許出願に記載された全ての内容を、本明細書を構成するものとして援用する。
本明細書または図面に説明した技術要素は、単独であるいは各種の組み合わせによって技術的有用性を発揮するものであり、出願時請求項記載の組み合わせに限定されるものではない。また、本明細書または図面に例示した技術は複数目的を同時に達成するものであり、そのうちの一つの目的を達成すること自体で技術的有用性を持つものである。
Claims (2)
- 表面と裏面を有し、前記表面にトレンチが形成されている半導体基板と、
前記トレンチ内の底部に配置されている底部絶縁層と、
前記底部絶縁層よりも前記表面側の前記トレンチの側面を覆っているゲート絶縁膜と、
前記底部絶縁層よりも前記表面側の前記トレンチ内に配置されており、前記底部絶縁層及び前記ゲート絶縁膜によって前記半導体基板から絶縁されているゲート電極、
を有しており、
前記半導体基板が、
前記ゲート絶縁膜に接する第1n型領域と、
前記第1n型領域の前記裏面側で前記ゲート絶縁膜に接する第1p型領域と、
前記底部絶縁層の前記裏面側の端部に接している第2p型領域と、
前記第1p型領域の前記裏面側に配置されており、前記第1p型領域によって前記第1n型領域から分離されており、前記ゲート絶縁膜及び前記底部絶縁層に接しており、前記第2p型領域よりも前記裏面側の位置まで伸びており、前記第2p型領域を前記第1p型領域から分離している第2n型領域、
を有しており、
前記第1p型領域の前記裏面側の端部から前記第2p型領域の前記表面側の端部までの距離Aと、前記底部絶縁層の前記裏面側の前記端部から前記第2p型領域の前記裏面側の端部までの距離Bとが、A<4Bの関係を満たし、
前記第2p型領域の前記表面側の前記端部から前記底部絶縁層の前記裏面側の前記端部までの距離Cが、前記第1p型領域の前記裏面側の前記端部から前記ゲート電極の前記裏面側の端部までの距離Dよりも小さい、
スイッチング素子。 - 前記半導体基板が、SiC系半導体により構成されており、
前記第2p型領域が、Alを含有している、
請求項1のスイッチング素子。
Priority Applications (4)
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DE112015003330.0T DE112015003330T5 (de) | 2014-07-18 | 2015-06-03 | Schaltvorrichtung |
US15/313,448 US20170213907A1 (en) | 2014-07-18 | 2015-06-03 | Switching device |
KR1020177004153A KR20170034899A (ko) | 2014-07-18 | 2015-06-03 | 스위칭 소자 |
CN201580039069.8A CN106537602A (zh) | 2014-07-18 | 2015-06-03 | 开关元件 |
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JP2014-147459 | 2014-07-18 | ||
JP2014147459A JP2016025177A (ja) | 2014-07-18 | 2014-07-18 | スイッチング素子 |
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WO2016009736A1 true WO2016009736A1 (ja) | 2016-01-21 |
Family
ID=55078239
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PCT/JP2015/066113 WO2016009736A1 (ja) | 2014-07-18 | 2015-06-03 | スイッチング素子 |
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US (1) | US20170213907A1 (ja) |
JP (1) | JP2016025177A (ja) |
KR (1) | KR20170034899A (ja) |
CN (1) | CN106537602A (ja) |
DE (1) | DE112015003330T5 (ja) |
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Cited By (1)
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CN106601795A (zh) * | 2016-11-25 | 2017-04-26 | 东莞市联洲知识产权运营管理有限公司 | 一种沟槽式场效应晶体管及其制造方法 |
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JP6560142B2 (ja) * | 2016-02-26 | 2019-08-14 | トヨタ自動車株式会社 | スイッチング素子 |
JP6560141B2 (ja) * | 2016-02-26 | 2019-08-14 | トヨタ自動車株式会社 | スイッチング素子 |
JP6299789B2 (ja) * | 2016-03-09 | 2018-03-28 | トヨタ自動車株式会社 | スイッチング素子 |
JP2018046254A (ja) * | 2016-09-16 | 2018-03-22 | トヨタ自動車株式会社 | スイッチング素子 |
JP6669628B2 (ja) * | 2016-10-20 | 2020-03-18 | トヨタ自動車株式会社 | スイッチング素子 |
JP2018085383A (ja) * | 2016-11-21 | 2018-05-31 | トヨタ自動車株式会社 | スイッチング素子 |
US10468509B2 (en) | 2017-06-07 | 2019-11-05 | Fuji Electric Co., Ltd. | Semiconductor device and method of manufacturing semiconductor device |
CN113690293B (zh) * | 2020-05-18 | 2024-04-12 | 华润微电子(重庆)有限公司 | Igbt器件及其制备方法 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01310576A (ja) * | 1988-06-08 | 1989-12-14 | Mitsubishi Electric Corp | 半導体装置およびその製造方法 |
JP2003069017A (ja) * | 2001-08-30 | 2003-03-07 | Shindengen Electric Mfg Co Ltd | トランジスタ、ダイオード |
JP2005116822A (ja) * | 2003-10-08 | 2005-04-28 | Toyota Motor Corp | 絶縁ゲート型半導体装置およびその製造方法 |
JP2005340626A (ja) * | 2004-05-28 | 2005-12-08 | Toshiba Corp | 半導体装置 |
JP2007129259A (ja) * | 1996-08-01 | 2007-05-24 | Kansai Electric Power Co Inc:The | 絶縁ゲート半導体装置 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0893830A1 (en) * | 1996-12-11 | 1999-01-27 | The Kansai Electric Power Co., Inc. | Insulated gate semiconductor device |
US6342709B1 (en) * | 1997-12-10 | 2002-01-29 | The Kansai Electric Power Co., Inc. | Insulated gate semiconductor device |
KR100767078B1 (ko) * | 2003-10-08 | 2007-10-15 | 도요다 지도샤 가부시끼가이샤 | 절연 게이트형 반도체 장치 및 그 제조 방법 |
FR2928270B1 (fr) * | 2008-03-10 | 2011-01-21 | Erytech Pharma | Formulation methode pour la prevention ou le traitement des metastases osseuses et autres maladies de l'os |
-
2014
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- 2015-06-03 KR KR1020177004153A patent/KR20170034899A/ko not_active Application Discontinuation
- 2015-06-03 WO PCT/JP2015/066113 patent/WO2016009736A1/ja active Application Filing
- 2015-06-03 US US15/313,448 patent/US20170213907A1/en not_active Abandoned
- 2015-06-03 CN CN201580039069.8A patent/CN106537602A/zh active Pending
- 2015-06-03 DE DE112015003330.0T patent/DE112015003330T5/de not_active Withdrawn
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Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01310576A (ja) * | 1988-06-08 | 1989-12-14 | Mitsubishi Electric Corp | 半導体装置およびその製造方法 |
JP2007129259A (ja) * | 1996-08-01 | 2007-05-24 | Kansai Electric Power Co Inc:The | 絶縁ゲート半導体装置 |
JP2003069017A (ja) * | 2001-08-30 | 2003-03-07 | Shindengen Electric Mfg Co Ltd | トランジスタ、ダイオード |
JP2005116822A (ja) * | 2003-10-08 | 2005-04-28 | Toyota Motor Corp | 絶縁ゲート型半導体装置およびその製造方法 |
JP2005340626A (ja) * | 2004-05-28 | 2005-12-08 | Toshiba Corp | 半導体装置 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106601795A (zh) * | 2016-11-25 | 2017-04-26 | 东莞市联洲知识产权运营管理有限公司 | 一种沟槽式场效应晶体管及其制造方法 |
CN106601795B (zh) * | 2016-11-25 | 2019-05-28 | 贵州芯长征科技有限公司 | 一种沟槽式场效应晶体管及其制造方法 |
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TWI575749B (zh) | 2017-03-21 |
DE112015003330T5 (de) | 2017-04-13 |
US20170213907A1 (en) | 2017-07-27 |
TW201622152A (zh) | 2016-06-16 |
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