USRE43840E1 - Silicon carbide semiconductor device - Google Patents

Silicon carbide semiconductor device Download PDF

Info

Publication number
USRE43840E1
USRE43840E1 US12/926,030 US92603010A USRE43840E US RE43840 E1 USRE43840 E1 US RE43840E1 US 92603010 A US92603010 A US 92603010A US RE43840 E USRE43840 E US RE43840E
Authority
US
United States
Prior art keywords
trench
silicon carbide
angle
plane
semiconductor device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US12/926,030
Inventor
Mitsuhiro Kataoka
Yuuichi Takeuchi
Masami Naito
Rajesh Kumar
Hiroyuki Matsunami
Tsunenobu Kimoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Denso Corp
Original Assignee
Denso Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Denso Corp filed Critical Denso Corp
Priority to US12/926,030 priority Critical patent/USRE43840E1/en
Application granted granted Critical
Publication of USRE43840E1 publication Critical patent/USRE43840E1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66053—Multistep manufacturing processes of devices having a semiconductor body comprising crystalline silicon carbide
    • 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
    • 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
    • H01L29/04—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes
    • H01L29/045—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes by their particular orientation of crystalline planes
    • 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
    • H01L29/80—Field effect transistors with field effect produced by a PN or other rectifying junction gate, i.e. potential-jump barrier
    • H01L29/808—Field effect transistors with field effect produced by a PN or other rectifying junction gate, i.e. potential-jump barrier with a PN junction gate, e.g. PN homojunction gate
    • H01L29/8083—Vertical transistors
    • 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

Definitions

  • the present invention relates to silicon carbide (SiC) semiconductor device where a facet is hindered from occurring.
  • JP-A-H9-172187 discloses a structure of a silicon carbide (SiC) substrate 200 having a trench 201 , wherein a silicon carbide epitaxial layer 202 is formed on an inside surface of the trench 200 .
  • the substrate 200 has a main surface of a (0001) plane and the trench 201 has side walls of a (1-100) plane, as shown in FIG. 28 .
  • FIGS. 29A , 29 B when the epitaxial layer 202 grows from the (1-100) planes within the trench 201 , a facet is formed in a vicinity of the surface. A defect cannot thereby be prevented. Namely, imbedded epitaxial growth on a wafer having an off-axis of a ⁇ 1-100> direction develops the (0001) facet downstream of the ⁇ 1-100> direction. This exhibits an asymmetric cross sectional shape of the epitaxial layer 202 that is deposited within the trench 201 , and causes the facet to have a rugged surface, resulting in being apt to develop a defect on the facet.
  • a facet is formed on a channel layer. This increases on-resistance due to lowered mobility and leak electric current, or varies a threshold value.
  • (1-100) or ⁇ 1-100> is equivalent to (0 1 00) or ⁇ 0 1 00> that is usually described in an expression method for a crystallographic plane or direction. Namely, “ ⁇ n” in an index reads “ n .”
  • a silicon carbide semiconductor device is provided with the following.
  • a silicon carbide substrate is provided as having an off-oriented ⁇ 0001 ⁇ surface whose off-axis direction is ⁇ 11-20> or ⁇ 1-100> and a trench is provided as having a stripe structure extending toward a ⁇ 11-20> or ⁇ 1-100> direction, respectively.
  • This structure restricts formation of a facet when an epitaxial layer grows on an inside surface of the trench.
  • Another silicon carbide semiconductor device is provided with a silicon carbide substrate that has an off-oriented ⁇ 0001 ⁇ surface whose off-axis direction is ⁇ 11-20> or ⁇ 1-100> and a trench that has a side wall of a ⁇ 1-100 ⁇ or ⁇ 11-20 ⁇ surface, respectively.
  • Another silicon carbide semiconductor device is provided with a silicon carbide substrate that has an off-oriented surface having a certain off-axis direction and a planar structure of a trench has sides, each of which is at an angle of 80 degrees or less, favorably at 75 degrees or less, with respect to the certain off-axis direction.
  • Another silicon carbide semiconductor device is provided with a silicon carbide substrate that has an off-oriented ⁇ 0001 ⁇ surface whose off-axis direction is ⁇ 11-20> or ⁇ 1-100> and a trench that has a side wall of ⁇ 11-20 ⁇ or ⁇ 1-100 ⁇ surface that is not perpendicular to the off-axis, respectively.
  • Yet another silicon carbide semiconductor device is provided with a silicon carbide substrate that is a hexagonal crystal silicon carbide substrate having a ⁇ 11-20 ⁇ or ⁇ 1-100 ⁇ main surface and a trench that has a side wall being slant at an angle of one degree or more with respect to a ⁇ 0001 ⁇ plane in a sectional structure.
  • FIG. 1A is a plan view for explaining an SiC semiconductor device according to a first embodiment of the present invention
  • FIG. 1B is a longitudinal sectional view taken along line 1 B- 1 B;
  • FIG. 2 is a longitudinal sectional view of the SiC semiconductor device according to the first embodiment
  • FIG. 3 is a longitudinal sectional view of a trench JFET
  • FIG. 4 is a longitudinal sectional view of the SiC semiconductor device according to the first embodiment
  • FIG. 5A is a plan view for explaining an SiC semiconductor device according to a second embodiment
  • FIG. 5B is a longitudinal sectional view taken along line 5 B- 5 B;
  • FIG. 6 is a longitudinal sectional view of the SiC semiconductor device according to the second embodiment.
  • FIG. 7 is a longitudinal sectional view of the SiC semiconductor device according to the second embodiment.
  • FIG. 8A is a plan view for explaining an SiC semiconductor device according to a third embodiment
  • FIG. 8B is a longitudinal sectional view taken along line 8 B- 8 B;
  • FIG. 9 is a longitudinal sectional view of the SiC semiconductor device according to the third embodiment.
  • FIG. 10A is a plan view for explaining a first modification of the SiC semiconductor device according to the third embodiment.
  • FIG. 10B is a longitudinal sectional view taken along line 10 B- 10 B;
  • FIG. 11A is a plan view for explaining a second modification of the SiC semiconductor device according to the third embodiment.
  • FIG. 11B is a longitudinal sectional view taken along line 11 B- 11 B;
  • FIG. 12 is a longitudinal sectional view of the second modification of the SiC semiconductor device according to the third embodiment.
  • FIG. 13A is a plan view for explaining another modification of the SiC semiconductor device according to the third embodiment.
  • FIG. 13B is a longitudinal sectional view taken along line 13 B- 13 B;
  • FIG. 14A is a plan view for explaining an SiC semiconductor device according to a fourth embodiment
  • FIG. 14B is a longitudinal sectional view taken along line 14 B- 14 B;
  • FIG. 15 is a longitudinal sectional view of the SiC semiconductor device according to the fourth embodiment.
  • FIG. 16A is a plan view for explaining a modification of the SiC semiconductor device according to the fourth embodiment.
  • FIG. 16B is a longitudinal sectional view taken along line 16 B- 16 B;
  • FIG. 17A is a plan view for explaining an SiC semiconductor device according to a fifth embodiment
  • FIG. 17B is a longitudinal sectional view taken along line 17 B- 17 B;
  • FIG. 18 is a longitudinal sectional view of the SiC semiconductor device according to the fifth embodiment.
  • FIG. 19 is a graph showing occurrence probability of a facet
  • FIG. 20A is a plan view for explaining an SiC semiconductor device according to a sixth embodiment
  • FIG. 20B is a longitudinal sectional view taken along line 20 B- 20 B;
  • FIG. 21 is a plan view for explaining a modification of the SiC semiconductor device according to the sixth embodiment.
  • FIG. 22A is a plan view for explaining an SiC semiconductor device according to a seventh embodiment
  • FIG. 22B is a longitudinal sectional view taken along line 22 B- 22 B;
  • FIG. 23 is a plan view for explaining a modification of the SiC semiconductor device according to the seventh embodiment.
  • FIG. 24A is a plan view for explaining an SiC semiconductor device according to an eighth embodiment.
  • FIG. 24B is a longitudinal sectional view taken along line 24 B- 24 B;
  • FIG. 25 is a longitudinal sectional view of the SiC semiconductor device according to the eighth embodiment.
  • FIG. 26A is a plan view for explaining an SiC semiconductor device according to a ninth embodiment.
  • FIG. 26B is a longitudinal sectional view taken along line 26 B- 26 B;
  • FIG. 27 is a longitudinal sectional view of the SiC semiconductor device according to the ninth embodiment.
  • FIG. 28 is a longitudinal sectional view of an SiC semiconductor device of a related art
  • FIG. 29A is a plan view for explaining the SiC semiconductor device of the related art.
  • FIG. 29B is a longitudinal sectional view taken along line 29 B- 29 B.
  • a silicon carbide (SiC) substrate (or wafer) 10 has a trench 11 on it.
  • the SiC substrate 10 has a ⁇ 11-20> off-oriented ⁇ 0001 ⁇ surface, which is a ⁇ 0001 ⁇ surface having an off angle and an off-axis direction of ⁇ 11-20>.
  • the trench 11 has a stripe structure extending toward a ⁇ 11-20> direction.
  • an SiC epitaxial layer 12 is formed within an inside surface of the trench 11 .
  • the SiC epitaxial layer 12 is formed on the SiC substrate 10 including the inside surface of the trench 11 .
  • the trench 11 is thus formed as having the stripe structure extending towards the ⁇ 11-20> direction, and the SiC layer 12 is formed on the SiC substrate 10 including the inside of the trench 11 .
  • an n + SiC substrate 13 an n ⁇ epitaxial layer 14 , a gate p + epitaxial layer 15 , a source n + epitaxial layer 16 are previously formed in order, and a trench 19 is then formed on the upper surface of the preceding layers.
  • the trench 19 penetrates through the source n + epitaxial layer 16 and the gate p + epitaxial layer 15 to reach the n ⁇ epitaxial layer 14 .
  • a channel n ⁇ epitaxial layer 17 and a gate p + epitaxial layer 18 are formed.
  • a drain electrode 13 a is formed as a back electrode. The first gate voltage is applied to the gate p + epitaxial layer 18 , while the second gate voltage is applied to the gate p + epitaxial layer 15 .
  • Adjusting a voltage between the gate p + epitaxial layer 18 and the gate p + epitaxial layer 15 leads to controlling expansion of a depletion layer in the channel n ⁇ epitaxial layer 17 between the gate p + epitaxial layer 18 and the gate p + epitaxial layer 15 .
  • the (1-100) plane can be the channel layer.
  • the trench 11 can be imbedded with an epitaxial layer 12 (imbedded epitaxial layer 12 ) as substitution of the epitaxial layer 12 shown in FIG. 2 .
  • a trench 11 has a stripe structure extending toward an off-axis direction along a line L 1 of FIG. 1 , and an epitaxial layer 12 is then formed on the surface of the wafer 10 including inside surfaces of the trench 11 . Since no facet is thereby formed when an epitaxial layer 12 grows, side walls of the trench 11 can be base surfaces for a channel layer.
  • a second embodiment is different from the first embodiment in an off-axis direction and an extending direction of a trench. Referring to FIGS. 5A , 5 B, 6 , the second embodiment will be explained below.
  • An SiC substrate 20 has a ⁇ 1-100> off-oriented ⁇ 0001 ⁇ surface.
  • a trench 21 has a stripe structure extending toward a ⁇ 1-100> direction.
  • the trench 21 is thus formed as having the stripe structure extending towards the ⁇ 1-100> direction, and an SiC layer 22 is formed on the SiC substrate 20 including the inside of the trench 21 .
  • the epitaxial layer 22 grows within the trench 21 , no facet is formed on (11-20) side walls of the trench 21 . Preventing formation of the facet enables the (11-20) plane to be a channel layer.
  • selecting a ⁇ 1-100> direction as an off-axis prevents a facet from being formed on a (11-20) plane having high mobility. This results in being favorable in forming a channel layer for an FET.
  • the trench 21 can be imbedded with an epitaxial layer 22 (imbedded epitaxial layer 22 ) as substitution of the epitaxial layer 22 shown in FIG. 6 .
  • a third embodiment is different from the first embodiment in a planar structure of a trench. Referring to FIGS. 8A , 8 B, 9 , the third embodiment will be explained below.
  • An SiC substrate 30 has a ⁇ 11-20> off-oriented ⁇ 0001 ⁇ surface.
  • a trench 31 has a regular hexagonal planar structure and side walls of a (1-100) plane, as shown in FIG. 8A .
  • An SiC layer 32 is formed on the SiC substrate 30 including the inside of the trench 31 , as shown in FIG. 9 .
  • the epitaxial layer 32 grows within the trench 31 , no facet is formed on (1-100) side walls of the trench 31 . Preventing formation of the facet enables the (1-100) plane to be a channel layer.
  • a trench 31 can be formed as having a long hexagonal planar structure instead of the regular hexagonal planar structure, like a stripe structure.
  • the stripe structure has a pair of two longitudinal sides that parallelly face to each other and two pairs of two short sides that form two triangular terminal ends.
  • each triangular terminal end is formed of two (1-100) planes that intersect to each other with an angle of 120 degrees. No facet is thereby formed also in the terminal ends of the trench 31 . This enables the terminal ends of the trench 31 , along with the longitudinal sides of the trench 31 , to be also used as a channel layer.
  • An SiC substrate 30 has a ⁇ 11-20> off-oriented ⁇ 0001 ⁇ surface.
  • a trench 33 has a regular triangular planar structure and side walls of a (1-100) plane, as shown in FIGS. 10A , 10 B.
  • An SiC layer (not shown) is formed on the SiC substrate 30 including the inside of the trench 33 .
  • the epitaxial layer grows within the trench 33 , no facet is formed on (1-100) side walls of the trench 31 . Preventing formation of the facet enables the (1-100) plane to be a channel layer.
  • FIGS. 11A , 11 B, 12 A second modification of the third embodiment will be explained with reference to FIGS. 11A , 11 B, 12 .
  • an SiC substrate 30 has a ⁇ 11-20> off-oriented ⁇ 0001 ⁇ surface and a trench 34 having side walls of a (1-100) plane is formed between regular triangles, as shown in FIGS. 11A , 11 B.
  • An SiC layer 35 is formed on the SiC substrate 30 including the inside of the trench 34 .
  • the epitaxial layer 35 grows within the trench 34 , no facet is formed on (1-100) side walls of the trench 34 . Preventing formation of the facet enables the (1-100) plane to be a channel layer.
  • FIGS. 13A , 13 B Furthermore, relationship, shown in FIG. 8A , between the substrate 30 and trench 31 is reversed in FIGS. 13A , 13 B. Namely, a trench 36 having side walls of a (1-100) plane is formed between hexagons, as shown in FIGS. 13A , 13 B.
  • a fourth embodiment is different from the third embodiment shown in FIG. 8A in an off-axis direction of a substrate and a plane index of side walls of a trench. Referring to FIGS. 14A , 14 B, 15 , the fourth embodiment will be explained below.
  • An SiC substrate 40 has a ⁇ 1-100> off-oriented ⁇ 0001 ⁇ surface.
  • a trench 41 has a regular hexagonal planar structure and side walls of a (11-20) plane, as shown in FIG. 14A .
  • An SiC layer 42 is formed on the SiC substrate 40 including the inside of the trench 41 , as shown in FIG. 15 .
  • the epitaxial layer 42 grows within the trench 41 , no facet is formed on (11-20) side walls of the trench 41 . Preventing formation of the facet enables the (11-20) plane to be a channel layer.
  • a trench 41 can be formed as having a long hexagonal planar structure instead of the regular hexagonal planar structure, like a stripe structure.
  • the stripe structure has a pair of two longitudinal sides that parallelly face to each other and two pairs of two short sides that form two triangular terminal ends.
  • each triangular terminal end is formed of two (11-20) planes that intersect to each other with an angle of 120 degrees. No facet is thereby formed also in the terminal ends of the trench 41 . This enables the terminal ends of the trench 41 , along with the longitudinal sides of the trench 41 , to be also used as a channel layer.
  • An SiC substrate 40 has a ⁇ 1-100> off-oriented ⁇ 0001 ⁇ surface.
  • a trench 43 has a regular triangular planar structure and side walls of a (11-20) plane.
  • An SiC layer (not shown) is formed on the SiC substrate 40 including the inside of the trench 43 .
  • no facet is formed on (11-20) side walls of the trench 43 . Preventing formation of the facet enables the (11-20) plane to be a channel layer.
  • a fifth embodiment will be explained mainly in difference from the first embodiment shown in FIGS. 1A , 1 B, with reference to FIGS. 17A , 17 B, 18 , 19 .
  • An SiC substrate 50 has a ⁇ 11-20> off-oriented ⁇ 0001 ⁇ surface, which is a ⁇ 0001 ⁇ surface having an off angle and an off-axis direction of ⁇ 11-20>.
  • a trench 51 has a planar structure of a rectangle. Each side of the rectangle is at an angle of 80 degrees or less, favorably 75 degrees or less, with respect to the off-axis direction.
  • both the angles ⁇ 1 , ⁇ 2 are 80 degrees or less, favorably 75 degrees or less.
  • the trench 51 is thus formed as having the sides at an angle of 80 degrees or less, favorably 75 degrees or less, with respect to the off-axis direction.
  • An SiC layer 52 is then formed on the SiC substrate 50 including the inside of the trench 51 , as shown in FIG. 18 .
  • whether a facet is formed on the side walls of the trench 51 when an epitaxial layer grows within the trench 51 depends on an angle ⁇ between the off-axis and each of the sides of the trench 51 . If the angle ⁇ is 75 degrees or less, no facet is formed.
  • FIG. 19 shows a measured result of formation probability of the facet based on the angle ⁇ .
  • formation probability of the facet is 100%.
  • formation probability of the facet is 0%.
  • a sixth embodiment will be explained mainly in difference from the first embodiment shown in FIGS. 1A , 1 B, with reference to FIGS. 20A , 20 B.
  • An SiC substrate 70 has a ⁇ 0001 ⁇ surface having an off angle and an off-axis direction of ⁇ 11-20>.
  • a trench 71 has side walls, each of which is a (11-20) plane and not perpendicular to the off-axis of the SiC substrate 70 , as shown in FIG. 20A . Pairs of mutually facing side walls come alternately near and away along an extending direction of the trench 71 .
  • the trench 71 is thus formed as having the side walls of (11-20) that include no (11-20) planes perpendicular to the off-axis of the substrate 70 . Therefore, when an epitaxial layer (not shown) grows within the trench 71 , no facet is formed.
  • the (11-20) planes of the side walls become the channel layer, which enables obtaining high channel mobility.
  • the trench 71 of this embodiment enables a greater channel width to thereby circulate a large electric current.
  • a trench 72 shown in FIG. 21 can be formed.
  • the trench 72 which also have side walls of a (11-20) plane, has a constant width along an extending direction of itself.
  • a seventh embodiment is different from the sixth embodiment in an off-axis direction of an SiC substrate and a plane index of side walls of a trench. Referring to FIGS. 22A , 22 B, the second embodiment will be explained below.
  • An SiC substrate 80 has a ⁇ 0001 ⁇ surface having an off angle and an off-axis direction of ⁇ 1-100>.
  • a trench 81 has side walls, each of which is a (1-100) plane and not perpendicular to the off-axis of the SiC substrate 80 , as shown in FIG. 22A . Pairs of mutually facing side walls come alternately near and away along an extending direction of the trench 81 .
  • the trench 81 is thus formed as having the side walls of (1-100) that include no (1-100) planes perpendicular to the off-axis of the substrate 80 . Therefore, when an epitaxial layer (not shown) grows within the trench 81 , no facet is formed.
  • this structure is applied to a device where the side walls of the trench is used as a channel layer, the (1-100) planes of the side walls become the channel layer, which enables obtaining high channel mobility.
  • the trench 81 of this embodiment enables a greater channel width to thereby circulate a large electric current.
  • a trench 82 shown in FIG. 23 can be formed.
  • the trench 82 which also have side walls of a (1-100) plane, has a constant width along an extending direction of itself.
  • An eight embodiment is different from the preceding embodiments in using an SiC substrate having no off angle.
  • an SiC substrate 90 is a hexagonal crystal SiC substrate having a ⁇ 11-20 ⁇ main surface without an off angle.
  • a trench 91 has side walls that are slant with being at an angle of one degree or more with respect to a (0001) plane in a sectional shape.
  • an epitaxial layer 92 grows within the trench 91 , no facet is formed.
  • this structure is applied to a device where the side walls of the trench is used as a channel layer, the (0001) planes of the side walls become the channel layers, which enables obtaining high channel mobility.
  • a ninth embodiment is different from the eighth embodiment in a plane index of a main surface of an SiC substrate. Referring to FIGS. 26A , 27 B, the ninth embodiment will be explained below.
  • An SiC substrate 100 is a hexagonal crystal SiC substrate having a ⁇ 1-100 ⁇ main surface without an off angle.
  • a trench 101 has side walls that are slant with being at an angle of one degree or more with respect to a (0001) plane in a sectional shape.
  • an epitaxial layer 102 grows within the trench 101 , no facet is formed.
  • this structure is applied to a device where the side walls of the trench is used as a channel layer, the (0001) planes of the side walls become the channel layers, which enables obtaining high channel mobility.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Physics & Mathematics (AREA)
  • Ceramic Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Junction Field-Effect Transistors (AREA)
  • Recrystallisation Techniques (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Abstract

A silicon carbide (SiC) substrate is provided with an off-oriented {0001} surface whose off-axis direction is <11-20>. A trench is formed on the SiC to have a stripe structure extending toward a <11-20> direction. An SiC epitaxial layer is formed on an inside surface of the trench.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
This application is based on and incorporates herein by reference Japanese Patent Application No. 2002-233722 filed on Aug. 9, 2002.
FIELD OF THE INVENTION
The present invention relates to silicon carbide (SiC) semiconductor device where a facet is hindered from occurring.
BACKGROUND OF THE INVENTION
In JP-A-H9-172187 discloses a structure of a silicon carbide (SiC) substrate 200 having a trench 201, wherein a silicon carbide epitaxial layer 202 is formed on an inside surface of the trench 200. Here, in order that electric field is inhibited from being concentrated on side walls of the trench 201, the substrate 200 has a main surface of a (0001) plane and the trench 201 has side walls of a (1-100) plane, as shown in FIG. 28.
In actual manufacturing, as shown in FIGS. 29A, 29B, when the epitaxial layer 202 grows from the (1-100) planes within the trench 201, a facet is formed in a vicinity of the surface. A defect cannot thereby be prevented. Namely, imbedded epitaxial growth on a wafer having an off-axis of a <1-100> direction develops the (0001) facet downstream of the <1-100> direction. This exhibits an asymmetric cross sectional shape of the epitaxial layer 202 that is deposited within the trench 201, and causes the facet to have a rugged surface, resulting in being apt to develop a defect on the facet.
When the above substrate is applied to a trench JFET, or a trench MOSFET, a facet is formed on a channel layer. This increases on-resistance due to lowered mobility and leak electric current, or varies a threshold value.
Incidentally, (1-100) or <1-100> is equivalent to (0 1 00) or <0 1 00> that is usually described in an expression method for a crystallographic plane or direction. Namely, “−n” in an index reads “ n.”
SUMMARY OF THE INVENTION
It is an object of the present invention to restrict formation of a facet when an epitaxial layer grows on an inside surface of a trench of a silicon carbide substrate.
To achieve the above object, a silicon carbide semiconductor device is provided with the following.
A silicon carbide substrate is provided as having an off-oriented {0001} surface whose off-axis direction is <11-20> or <1-100> and a trench is provided as having a stripe structure extending toward a <11-20> or <1-100> direction, respectively.
This structure restricts formation of a facet when an epitaxial layer grows on an inside surface of the trench.
Furthermore, to achieve the same object to thereby enable the same effect, other silicon carbide semiconductor devices are differently provided as follows.
Another silicon carbide semiconductor device is provided with a silicon carbide substrate that has an off-oriented {0001} surface whose off-axis direction is <11-20> or <1-100> and a trench that has a side wall of a {1-100} or {11-20} surface, respectively.
Another silicon carbide semiconductor device is provided with a silicon carbide substrate that has an off-oriented surface having a certain off-axis direction and a planar structure of a trench has sides, each of which is at an angle of 80 degrees or less, favorably at 75 degrees or less, with respect to the certain off-axis direction.
Another silicon carbide semiconductor device is provided with a silicon carbide substrate that has an off-oriented {0001} surface whose off-axis direction is <11-20> or <1-100> and a trench that has a side wall of {11-20} or {1-100} surface that is not perpendicular to the off-axis, respectively.
Yet another silicon carbide semiconductor device is provided with a silicon carbide substrate that is a hexagonal crystal silicon carbide substrate having a {11-20} or {1-100} main surface and a trench that has a side wall being slant at an angle of one degree or more with respect to a {0001} plane in a sectional structure.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
FIG. 1A is a plan view for explaining an SiC semiconductor device according to a first embodiment of the present invention;
FIG. 1B is a longitudinal sectional view taken along line 1B-1B;
FIG. 2 is a longitudinal sectional view of the SiC semiconductor device according to the first embodiment;
FIG. 3 is a longitudinal sectional view of a trench JFET;
FIG. 4 is a longitudinal sectional view of the SiC semiconductor device according to the first embodiment;
FIG. 5A is a plan view for explaining an SiC semiconductor device according to a second embodiment;
FIG. 5B is a longitudinal sectional view taken along line 5B-5B;
FIG. 6 is a longitudinal sectional view of the SiC semiconductor device according to the second embodiment;
FIG. 7 is a longitudinal sectional view of the SiC semiconductor device according to the second embodiment;
FIG. 8A is a plan view for explaining an SiC semiconductor device according to a third embodiment;
FIG. 8B is a longitudinal sectional view taken along line 8B-8B;
FIG. 9 is a longitudinal sectional view of the SiC semiconductor device according to the third embodiment;
FIG. 10A is a plan view for explaining a first modification of the SiC semiconductor device according to the third embodiment;
FIG. 10B is a longitudinal sectional view taken along line 10B-10B;
FIG. 11A is a plan view for explaining a second modification of the SiC semiconductor device according to the third embodiment;
FIG. 11B is a longitudinal sectional view taken along line 11B-11B;
FIG. 12 is a longitudinal sectional view of the second modification of the SiC semiconductor device according to the third embodiment;
FIG. 13A is a plan view for explaining another modification of the SiC semiconductor device according to the third embodiment;
FIG. 13B is a longitudinal sectional view taken along line 13B-13B;
FIG. 14A is a plan view for explaining an SiC semiconductor device according to a fourth embodiment;
FIG. 14B is a longitudinal sectional view taken along line 14B-14B;
FIG. 15 is a longitudinal sectional view of the SiC semiconductor device according to the fourth embodiment;
FIG. 16A is a plan view for explaining a modification of the SiC semiconductor device according to the fourth embodiment;
FIG. 16B is a longitudinal sectional view taken along line 16B-16B;
FIG. 17A is a plan view for explaining an SiC semiconductor device according to a fifth embodiment;
FIG. 17B is a longitudinal sectional view taken along line 17B-17B;
FIG. 18 is a longitudinal sectional view of the SiC semiconductor device according to the fifth embodiment;
FIG. 19 is a graph showing occurrence probability of a facet;
FIG. 20A is a plan view for explaining an SiC semiconductor device according to a sixth embodiment;
FIG. 20B is a longitudinal sectional view taken along line 20B-20B;
FIG. 21 is a plan view for explaining a modification of the SiC semiconductor device according to the sixth embodiment;
FIG. 22A is a plan view for explaining an SiC semiconductor device according to a seventh embodiment;
FIG. 22B is a longitudinal sectional view taken along line 22B-22B;
FIG. 23 is a plan view for explaining a modification of the SiC semiconductor device according to the seventh embodiment;
FIG. 24A is a plan view for explaining an SiC semiconductor device according to an eighth embodiment;
FIG. 24B is a longitudinal sectional view taken along line 24B-24B;
FIG. 25 is a longitudinal sectional view of the SiC semiconductor device according to the eighth embodiment;
FIG. 26A is a plan view for explaining an SiC semiconductor device according to a ninth embodiment;
FIG. 26B is a longitudinal sectional view taken along line 26B-26B;
FIG. 27 is a longitudinal sectional view of the SiC semiconductor device according to the ninth embodiment;
FIG. 28 is a longitudinal sectional view of an SiC semiconductor device of a related art;
FIG. 29A is a plan view for explaining the SiC semiconductor device of the related art; and
FIG. 29B is a longitudinal sectional view taken along line 29B-29B.
 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(First Embodiment)
A first embodiment will be explained with reference to FIGS. 1A to 1B. A silicon carbide (SiC) substrate (or wafer) 10 has a trench 11 on it. The SiC substrate 10 has a <11-20> off-oriented {0001} surface, which is a {0001} surface having an off angle and an off-axis direction of <11-20>. The trench 11 has a stripe structure extending toward a <11-20> direction. As shown in FIG. 2, within an inside surface of the trench 11, an SiC epitaxial layer 12 is formed. In detail, the SiC epitaxial layer 12 is formed on the SiC substrate 10 including the inside surface of the trench 11.
On the <11-20> off-oriented SiC wafer 10, the trench 11 is thus formed as having the stripe structure extending towards the <11-20> direction, and the SiC layer 12 is formed on the SiC substrate 10 including the inside of the trench 11.
Therefore, when the epitaxial layer 12 grows within the trench 11, no facet is formed on the (1-100) side wall of the trench 11. Preventing formation of the facet enables the (1-100) plane to be a channel layer. This is favorable for being applied to a trench JFET shown in FIG. 3. In detail, on an n+ SiC substrate 13, an n− epitaxial layer 14, a gate p+ epitaxial layer 15, a source n+ epitaxial layer 16 are previously formed in order, and a trench 19 is then formed on the upper surface of the preceding layers. The trench 19 penetrates through the source n+ epitaxial layer 16 and the gate p+ epitaxial layer 15 to reach the n− epitaxial layer 14. Within the trench 19, a channel n− epitaxial layer 17 and a gate p+ epitaxial layer 18 are formed. On the n+ SiC substrate 13, a drain electrode 13a is formed as a back electrode. The first gate voltage is applied to the gate p+ epitaxial layer 18, while the second gate voltage is applied to the gate p+ epitaxial layer 15. Adjusting a voltage between the gate p+ epitaxial layer 18 and the gate p+ epitaxial layer 15 leads to controlling expansion of a depletion layer in the channel n− epitaxial layer 17 between the gate p+ epitaxial layer 18 and the gate p+ epitaxial layer 15. This results in enabling controlling an electric current that flows between the source and the drain (between the source n+ epitaxial layer 16 and the n+ SiC substrate 13). Here, as explained in FIGS. 1A, 1B, 2, the (1-100) plane can be the channel layer.
In addition, as shown in FIG. 4, the trench 11 can be imbedded with an epitaxial layer 12 (imbedded epitaxial layer 12) as substitution of the epitaxial layer 12 shown in FIG. 2.
As described above, using an off-oriented wafer 10, a trench 11 has a stripe structure extending toward an off-axis direction along a line L1 of FIG. 1, and an epitaxial layer 12 is then formed on the surface of the wafer 10 including inside surfaces of the trench 11. Since no facet is thereby formed when an epitaxial layer 12 grows, side walls of the trench 11 can be base surfaces for a channel layer.
(Second Embodiment)
A second embodiment is different from the first embodiment in an off-axis direction and an extending direction of a trench. Referring to FIGS. 5A, 5B, 6, the second embodiment will be explained below.
An SiC substrate 20 has a <1-100> off-oriented {0001} surface. A trench 21 has a stripe structure extending toward a <1-100> direction.
On the <1-100> off-oriented SiC wafer 20, the trench 21 is thus formed as having the stripe structure extending towards the <1-100> direction, and an SiC layer 22 is formed on the SiC substrate 20 including the inside of the trench 21.
Therefore, when the epitaxial layer 22 grows within the trench 21, no facet is formed on (11-20) side walls of the trench 21. Preventing formation of the facet enables the (11-20) plane to be a channel layer.
In other words, selecting a <1-100> direction as an off-axis prevents a facet from being formed on a (11-20) plane having high mobility. This results in being favorable in forming a channel layer for an FET.
In addition, as shown in FIG. 7, the trench 21 can be imbedded with an epitaxial layer 22 (imbedded epitaxial layer 22) as substitution of the epitaxial layer 22 shown in FIG. 6.
(Third Embodiment)
A third embodiment is different from the first embodiment in a planar structure of a trench. Referring to FIGS. 8A, 8B, 9, the third embodiment will be explained below.
An SiC substrate 30 has a <11-20> off-oriented {0001} surface. A trench 31 has a regular hexagonal planar structure and side walls of a (1-100) plane, as shown in FIG. 8A. An SiC layer 32 is formed on the SiC substrate 30 including the inside of the trench 31, as shown in FIG. 9.
Therefore, when the epitaxial layer 32 grows within the trench 31, no facet is formed on (1-100) side walls of the trench 31. Preventing formation of the facet enables the (1-100) plane to be a channel layer.
Furthermore, a trench 31 can be formed as having a long hexagonal planar structure instead of the regular hexagonal planar structure, like a stripe structure. The stripe structure has a pair of two longitudinal sides that parallelly face to each other and two pairs of two short sides that form two triangular terminal ends. Here, each triangular terminal end is formed of two (1-100) planes that intersect to each other with an angle of 120 degrees. No facet is thereby formed also in the terminal ends of the trench 31. This enables the terminal ends of the trench 31, along with the longitudinal sides of the trench 31, to be also used as a channel layer.
A first modification of the third embodiment will be explained with reference to FIGS. 10A, 10B.
An SiC substrate 30 has a <11-20> off-oriented {0001} surface. A trench 33 has a regular triangular planar structure and side walls of a (1-100) plane, as shown in FIGS. 10A, 10B. An SiC layer (not shown) is formed on the SiC substrate 30 including the inside of the trench 33. When the epitaxial layer grows within the trench 33, no facet is formed on (1-100) side walls of the trench 31. Preventing formation of the facet enables the (1-100) plane to be a channel layer.
A second modification of the third embodiment will be explained with reference to FIGS. 11A, 11B, 12.
Relationship, shown in FIG. 10A, between the substrate 30 and trench 33 is reversed in FIGS. 11A, 11B. Namely, an SiC substrate 30 has a <11-20> off-oriented {0001} surface and a trench 34 having side walls of a (1-100) plane is formed between regular triangles, as shown in FIGS. 11A, 11B. An SiC layer 35 is formed on the SiC substrate 30 including the inside of the trench 34. When the epitaxial layer 35 grows within the trench 34, no facet is formed on (1-100) side walls of the trench 34. Preventing formation of the facet enables the (1-100) plane to be a channel layer.
Furthermore, relationship, shown in FIG. 8A, between the substrate 30 and trench 31 is reversed in FIGS. 13A, 13B. Namely, a trench 36 having side walls of a (1-100) plane is formed between hexagons, as shown in FIGS. 13A, 13B.
(Fourth Embodiment)
A fourth embodiment is different from the third embodiment shown in FIG. 8A in an off-axis direction of a substrate and a plane index of side walls of a trench. Referring to FIGS. 14A, 14B, 15, the fourth embodiment will be explained below.
An SiC substrate 40 has a <1-100> off-oriented {0001} surface. A trench 41 has a regular hexagonal planar structure and side walls of a (11-20) plane, as shown in FIG. 14A. An SiC layer 42 is formed on the SiC substrate 40 including the inside of the trench 41, as shown in FIG. 15.
Therefore, when the epitaxial layer 42 grows within the trench 41, no facet is formed on (11-20) side walls of the trench 41. Preventing formation of the facet enables the (11-20) plane to be a channel layer.
Furthermore, a trench 41 can be formed as having a long hexagonal planar structure instead of the regular hexagonal planar structure, like a stripe structure. The stripe structure has a pair of two longitudinal sides that parallelly face to each other and two pairs of two short sides that form two triangular terminal ends. Here, each triangular terminal end is formed of two (11-20) planes that intersect to each other with an angle of 120 degrees. No facet is thereby formed also in the terminal ends of the trench 41. This enables the terminal ends of the trench 41, along with the longitudinal sides of the trench 41, to be also used as a channel layer.
A modification of the fourth embodiment will be explained with reference to FIGS. 16A, 16B.
An SiC substrate 40 has a <1-100> off-oriented {0001} surface. A trench 43 has a regular triangular planar structure and side walls of a (11-20) plane. An SiC layer (not shown) is formed on the SiC substrate 40 including the inside of the trench 43. When the epitaxial layer grows within the trench 43, no facet is formed on (11-20) side walls of the trench 43. Preventing formation of the facet enables the (11-20) plane to be a channel layer.
(Fifth Embodiment)
A fifth embodiment will be explained mainly in difference from the first embodiment shown in FIGS. 1A, 1B, with reference to FIGS. 17A, 17B, 18, 19.
An SiC substrate 50 has a <11-20> off-oriented {0001} surface, which is a {0001} surface having an off angle and an off-axis direction of <11-20>. A trench 51 has a planar structure of a rectangle. Each side of the rectangle is at an angle of 80 degrees or less, favorably 75 degrees or less, with respect to the off-axis direction. In detail, the longitudinal sides of the rectangle are at an angle θ1 with respect to the off-axis direction, while the lateral sides are at an angle θ2 (acute angle: θ2=90−θ1) with respect to the off-axis direction. Here, both the angles θ1, θ2 are 80 degrees or less, favorably 75 degrees or less.
On the off-oriented SiC wafer 50, the trench 51 is thus formed as having the sides at an angle of 80 degrees or less, favorably 75 degrees or less, with respect to the off-axis direction. An SiC layer 52 is then formed on the SiC substrate 50 including the inside of the trench 51, as shown in FIG. 18.
Here, whether a facet is formed on the side walls of the trench 51 when an epitaxial layer grows within the trench 51 depends on an angle θ between the off-axis and each of the sides of the trench 51. If the angle θ is 75 degrees or less, no facet is formed.
FIG. 19 shows a measured result of formation probability of the facet based on the angle θ. When the angle θ is 90 degrees, formation probability of the facet is 100%. By contrast, when the angle θ is 75 degrees or less, formation probability of the facet is 0%.
This indicates that all the sides of the planar structure of the trench 51 should be at an angle of 80 degrees or less, favorably 75 degrees or less, with respect to the off-axis of the SiC substrate 50.
(Sixth Embodiment)
A sixth embodiment will be explained mainly in difference from the first embodiment shown in FIGS. 1A, 1B, with reference to FIGS. 20A, 20B.
An SiC substrate 70 has a {0001} surface having an off angle and an off-axis direction of <11-20>. A trench 71 has side walls, each of which is a (11-20) plane and not perpendicular to the off-axis of the SiC substrate 70, as shown in FIG. 20A. Pairs of mutually facing side walls come alternately near and away along an extending direction of the trench 71.
On the <11-20> off-oriented SiC wafer 70, the trench 71 is thus formed as having the side walls of (11-20) that include no (11-20) planes perpendicular to the off-axis of the substrate 70. Therefore, when an epitaxial layer (not shown) grows within the trench 71, no facet is formed. When this structure is applied to a device where the side walls of the trench is used as a channel layer, the (11-20) planes of the side walls become the channel layer, which enables obtaining high channel mobility.
Furthermore, in comparison with the trench having the stripe structure linearly extending as shown in FIG. 1A, the trench 71 of this embodiment enables a greater channel width to thereby circulate a large electric current.
As a modification of the sixth embodiment, a trench 72 shown in FIG. 21 can be formed. The trench 72, which also have side walls of a (11-20) plane, has a constant width along an extending direction of itself.
(Seventh Embodiment)
A seventh embodiment is different from the sixth embodiment in an off-axis direction of an SiC substrate and a plane index of side walls of a trench. Referring to FIGS. 22A, 22B, the second embodiment will be explained below.
An SiC substrate 80 has a {0001} surface having an off angle and an off-axis direction of <1-100>. A trench 81 has side walls, each of which is a (1-100) plane and not perpendicular to the off-axis of the SiC substrate 80, as shown in FIG. 22A. Pairs of mutually facing side walls come alternately near and away along an extending direction of the trench 81.
On the <1-100> off-oriented SiC wafer 80, the trench 81 is thus formed as having the side walls of (1-100) that include no (1-100) planes perpendicular to the off-axis of the substrate 80. Therefore, when an epitaxial layer (not shown) grows within the trench 81, no facet is formed. When this structure is applied to a device where the side walls of the trench is used as a channel layer, the (1-100) planes of the side walls become the channel layer, which enables obtaining high channel mobility.
Furthermore, in comparison with the trench having the stripe structure linearly extending as shown in FIG. 1A, the trench 81 of this embodiment enables a greater channel width to thereby circulate a large electric current.
As a modification of the sixth embodiment, a trench 82 shown in FIG. 23 can be formed. The trench 82, which also have side walls of a (1-100) plane, has a constant width along an extending direction of itself.
(Eighth Embodiment)
An eight embodiment is different from the preceding embodiments in using an SiC substrate having no off angle.
As shown in FIGS. 24A, 24B, an SiC substrate 90 is a hexagonal crystal SiC substrate having a {11-20} main surface without an off angle. A trench 91 has side walls that are slant with being at an angle of one degree or more with respect to a (0001) plane in a sectional shape. Here, in this structure, when an epitaxial layer 92 grows within the trench 91, no facet is formed. Furthermore, when this structure is applied to a device where the side walls of the trench is used as a channel layer, the (0001) planes of the side walls become the channel layers, which enables obtaining high channel mobility.
(Ninth Embodiment)
A ninth embodiment is different from the eighth embodiment in a plane index of a main surface of an SiC substrate. Referring to FIGS. 26A, 27B, the ninth embodiment will be explained below.
An SiC substrate 100 is a hexagonal crystal SiC substrate having a {1-100} main surface without an off angle. A trench 101 has side walls that are slant with being at an angle of one degree or more with respect to a (0001) plane in a sectional shape. Here, in the above structure, when an epitaxial layer 102 grows within the trench 101, no facet is formed. Furthermore, when this structure is applied to a device where the side walls of the trench is used as a channel layer, the (0001) planes of the side walls become the channel layers, which enables obtaining high channel mobility.
It will be obvious to those skilled in the art that various changes may be made in the above-described embodiments of the present invention. However, the scope of the present invention should be determined by the following claims.

Claims (10)

1. A silicon carbide semiconductor device comprising:
a silicon carbide substrate having a top surface that is a {0001} plane having an off angle, wherein an off-axis direction of the off angle is <11-20>; and
a trench that is formed on the top surface of the silicon carbide substrate and has a stripe structure extending toward a <11-20> direction of the top surface of the silicon carbide substrate,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
2. A silicon carbide semiconductor device comprising:
a silicon carbide substrate having a top surface that is a {0001} plane having an off angle, wherein an off-axis direction of the off angle is <1-100>; and
a trench that is formed on the top surface of the silicon carbide substrate and has a stripe structure extending toward a <1-100> direction of the top surface of the silicon carbide substrate,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
3. A silicon carbide semiconductor device comprising:
a silicon carbide substrate having a top surface that is in a {0001} plane having an off angle, wherein an off-axis direction of the off angle is <11-20>; and
a trench that is formed on the top surface of the silicon carbide substrate, wherein the trench has a side wall having a surface that is in a {1-1001} plane.
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
4. A silicon carbide semiconductor device comprising:
a silicon carbide substrate having a top surface that is in a {0001} plane having an off angle, wherein an off-axis direction of the off angle is <1-100>; and
a trench that is formed on the top surface of the silicon carbide substrate, wherein the trench has a side wall having a surface that is in a {11-20} plane,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
5. A silicon carbide semiconductor device comprising:
a silicon carbide substrate having a top surface that is in a plane having an off angle, wherein an off-axis direction of the off angle is a certain direction; and
a trench that is formed on the top surface of the silicon carbide substrate, wherein the trench has a planar structure, wherein each side of the planar structure is at an angle of 80 degrees or less with respect to the certain direction,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
6. A silicon carbide semiconductor device comprising:
a silicon carbide substrate having a top surface that is in a plane having an off angle, wherein an off-axis direction of the off angle is a certain direction; and
a trench that is formed on the top surface of the silicon carbide substrate, wherein the trench has a planar structure, wherein each side of the planar structure is at an angle of 75 degrees or less with respect to the certain direction,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
7. A silicon carbide semiconductor device comprising:
a silicon carbide substrate having a top surface that is in a {0001} plane having an off angle, wherein an off-axis direction of the off angle is <11-20>; and
a trench that is formed on the top surface of the silicon carbide substrate, wherein the trench has a side wall having a surface that is in a {11-20} plane and is not perpendicular to the off-axis direction,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
8. A silicon carbide semiconductor device comprising:
a silicon carbide substrate having a top surface that is a {0001} plane having an off angle, wherein an off-axis direction of the off angle is <1-100>; and
a trench that is formed on the top surface of the silicon carbide substrate, wherein the trench has a side wall having a surface that is in a {1-100} plane and is not perpendicular to the off-axis direction,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
9. A silicon carbide semiconductor device comprising:
a silicon carbide substrate that is a hexagonal crystal silicon carbide substrate having a top surface that is in a {11-20} plane; and
a trench that is formed on the top surface of the silicon carbide substrate, wherein the trench has a side wall that is inclined at an angle of one degree or more with respect to a {0001} plane in a virtual cross-sectional view that is perpendicular to the top surface of the silicon carbide substrate,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
10. A silicon carbide semiconductor device comprising:
a silicon carbide substrate being a hexagonal crystal silicon carbide substrate having a top surface that is in a {1-100} lane plane; and
a trench that is formed on the top surface of the silicon carbide substrate and has a side wall that is inclined at an angle of one degree or more with respect to a {0001} plane in a virtual cross-sectional view that is perpendicular to the top surface of the silicon carbide substrate,
wherein a silicon carbide epitaxial layer is formed on an inside surface of the trench.
US12/926,030 2002-08-09 2010-10-21 Silicon carbide semiconductor device Expired - Lifetime USRE43840E1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/926,030 USRE43840E1 (en) 2002-08-09 2010-10-21 Silicon carbide semiconductor device

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2002233722A JP4110875B2 (en) 2002-08-09 2002-08-09 Silicon carbide semiconductor device
JP2002-233722 2002-08-09
US10/630,978 US6853006B2 (en) 2002-08-09 2003-07-31 Silicon carbide semiconductor device
US12/926,030 USRE43840E1 (en) 2002-08-09 2010-10-21 Silicon carbide semiconductor device

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US10/630,978 Reissue US6853006B2 (en) 2002-08-09 2003-07-31 Silicon carbide semiconductor device

Publications (1)

Publication Number Publication Date
USRE43840E1 true USRE43840E1 (en) 2012-12-04

Family

ID=31185141

Family Applications (2)

Application Number Title Priority Date Filing Date
US10/630,978 Ceased US6853006B2 (en) 2002-08-09 2003-07-31 Silicon carbide semiconductor device
US12/926,030 Expired - Lifetime USRE43840E1 (en) 2002-08-09 2010-10-21 Silicon carbide semiconductor device

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US10/630,978 Ceased US6853006B2 (en) 2002-08-09 2003-07-31 Silicon carbide semiconductor device

Country Status (4)

Country Link
US (2) US6853006B2 (en)
JP (1) JP4110875B2 (en)
CN (1) CN1327528C (en)
DE (1) DE10334819B4 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9425262B2 (en) 2014-05-29 2016-08-23 Fairchild Semiconductor Corporation Configuration of portions of a power device within a silicon carbide crystal

Families Citing this family (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4179147B2 (en) * 2003-11-28 2008-11-12 株式会社デンソー Silicon carbide semiconductor device
US7173285B2 (en) * 2004-03-18 2007-02-06 Cree, Inc. Lithographic methods to reduce stacking fault nucleation sites
CN100533663C (en) * 2004-03-18 2009-08-26 克里公司 Lithographic methods to reduce stacking fault nucleation sites and structures having reduced stacking fault nucleation sites
US7109521B2 (en) * 2004-03-18 2006-09-19 Cree, Inc. Silicon carbide semiconductor structures including multiple epitaxial layers having sidewalls
SE527205C2 (en) * 2004-04-14 2006-01-17 Denso Corp Process for manufacturing semiconductor device with channel in silicon carbide semiconductor substrate
US7820511B2 (en) 2004-07-08 2010-10-26 Semisouth Laboratories, Inc. Normally-off integrated JFET power switches in wide bandgap semiconductors and methods of making
EP1619276B1 (en) * 2004-07-19 2017-01-11 Norstel AB Homoepitaxial growth of SiC on low off-axis SiC wafers
JP4830285B2 (en) * 2004-11-08 2011-12-07 株式会社デンソー Method for manufacturing silicon carbide semiconductor device
US7834380B2 (en) * 2004-12-09 2010-11-16 Panasonic Corporation Field effect transistor and method for fabricating the same
JP5196513B2 (en) * 2005-03-09 2013-05-15 独立行政法人産業技術総合研究所 Silicon carbide transistor device
JP5017823B2 (en) * 2005-09-12 2012-09-05 富士電機株式会社 Manufacturing method of semiconductor device
JP5068009B2 (en) * 2005-09-14 2012-11-07 三菱電機株式会社 Silicon carbide semiconductor device
US20070152238A1 (en) * 2005-11-18 2007-07-05 General Electric Company Heterostructure field effect transistor and associated method
US7521732B2 (en) * 2005-11-18 2009-04-21 General Electric Company Vertical heterostructure field effect transistor and associated method
US7314799B2 (en) * 2005-12-05 2008-01-01 Semisouth Laboratories, Inc. Self-aligned trench field effect transistors with regrown gates and bipolar junction transistors with regrown base contact regions and methods of making
EP1972008B1 (en) * 2006-01-10 2020-05-13 Cree, Inc. Silicon carbide dimpled substrate
DE102006032636A1 (en) * 2006-07-13 2008-01-17 Schunk Kohlenstofftechnik Gmbh Method for producing a ceramic substrate and ceramic substrate
US7595241B2 (en) * 2006-08-23 2009-09-29 General Electric Company Method for fabricating silicon carbide vertical MOSFET devices
JP2008108844A (en) * 2006-10-24 2008-05-08 Toyota Central R&D Labs Inc Group iii nitride semiconductor device having trench or mesa-structure, and manufacturing method thereof
US7691711B2 (en) * 2008-01-31 2010-04-06 General Electric Company Method for fabricating silicon carbide vertical MOSFET devices
JP5432488B2 (en) * 2008-09-02 2014-03-05 関西電力株式会社 Bipolar semiconductor device
US7906427B2 (en) * 2008-10-14 2011-03-15 General Electric Company Dimension profiling of SiC devices
JP2012146921A (en) * 2011-01-14 2012-08-02 Denso Corp Silicon carbide semiconductor device
JP5668576B2 (en) * 2011-04-01 2015-02-12 住友電気工業株式会社 Silicon carbide semiconductor device
JP5817204B2 (en) * 2011-04-28 2015-11-18 トヨタ自動車株式会社 Silicon carbide semiconductor device
JP5424219B2 (en) * 2011-07-07 2014-02-26 独立行政法人産業技術総合研究所 Method for manufacturing silicon carbide transistor device
WO2013031172A1 (en) * 2011-08-26 2013-03-07 国立大学法人奈良先端科学技術大学院大学 SiC SEMICONDUCTOR ELEMENT AND MANUFACTURING METHOD THEREOF
WO2013042333A1 (en) * 2011-09-22 2013-03-28 パナソニック株式会社 Silicon carbide semiconductor element and method for manufacturing same
JP5995521B2 (en) * 2012-05-18 2016-09-21 キヤノン株式会社 Lens barrel and camera system
US20140191241A1 (en) * 2013-01-07 2014-07-10 Avogy, Inc. Gallium nitride vertical jfet with hexagonal cell structure
JP6107453B2 (en) * 2013-06-13 2017-04-05 住友電気工業株式会社 Method for manufacturing silicon carbide semiconductor device
US9024328B2 (en) * 2013-07-02 2015-05-05 General Electric Company Metal-oxide-semiconductor (MOS) devices with increased channel periphery and methods of manufacture
JP2015159138A (en) * 2014-02-21 2015-09-03 豊田合成株式会社 Semiconductor device and manufacturing method of the same
JP6928336B2 (en) * 2016-12-28 2021-09-01 富士電機株式会社 Silicon Carbide Semiconductor Device and Method for Manufacturing Silicon Carbide Semiconductor Device
JP6762484B2 (en) * 2017-01-10 2020-09-30 昭和電工株式会社 SiC epitaxial wafer and its manufacturing method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06227886A (en) 1993-02-05 1994-08-16 Toshiba Corp Production of semiconductor single crystal
JPH09172187A (en) 1995-12-19 1997-06-30 Hitachi Ltd Junction type field-effect semiconductor device and its manufacture
US5736753A (en) 1994-09-12 1998-04-07 Hitachi, Ltd. Semiconductor device for improved power conversion having a hexagonal-system single-crystal silicon carbide

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992022922A2 (en) * 1991-06-12 1992-12-23 Case Western Reserve University Process for the controlled growth of single-crystal films of silicon carbide polytypes on silicon carbide wafers
EP0676814B1 (en) * 1994-04-06 2006-03-22 Denso Corporation Process of producing trench semiconductor device
JPH10125904A (en) * 1996-10-17 1998-05-15 Denso Corp Silicon carbide semiconductor device
US6121633A (en) * 1997-06-12 2000-09-19 Cree Research, Inc. Latch-up free power MOS-bipolar transistor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06227886A (en) 1993-02-05 1994-08-16 Toshiba Corp Production of semiconductor single crystal
US5736753A (en) 1994-09-12 1998-04-07 Hitachi, Ltd. Semiconductor device for improved power conversion having a hexagonal-system single-crystal silicon carbide
JPH09172187A (en) 1995-12-19 1997-06-30 Hitachi Ltd Junction type field-effect semiconductor device and its manufacture

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
N. Nordell, et al., "Equilibrium crystal shapes for 6H and 4H SiC grown on non-planar substrates," Materials Science and Engineering, B61-62:130-134, 1999.
N. Nordell, et al., "Homoepitaxy of 6H and 4H SiC on nonplanar substrates," Appl. Phys. Lett. 72(2): 197-199, Jan. 12, 1998.
Office Action dated Aug. 31, 2007 from the Japan Patent Office in the corresponding patent application No. 2002-233722 (and English translation).
Office Action dated Aug. 4, 2010 from the German Patent Office in the corresponding patent application No. 103 34 819.0 (and English translation).
Office Action dated Dec. 17, 2004 from the Chinese Patent Office in the corresponding patent application No. 031525903 (and English translation).
Office Action dated Feb. 12, 2010 from the German Patent Office in the corresponding patent application No. 103 34 819.0 (and English translation).
Office Action mailed Feb. 9, 2011 issued from the German Patent Office in corresponding De patent application No. 103 34 819.0-33 (English translation enclosed).

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9425262B2 (en) 2014-05-29 2016-08-23 Fairchild Semiconductor Corporation Configuration of portions of a power device within a silicon carbide crystal

Also Published As

Publication number Publication date
CN1481030A (en) 2004-03-10
CN1327528C (en) 2007-07-18
JP4110875B2 (en) 2008-07-02
DE10334819B4 (en) 2014-08-21
US6853006B2 (en) 2005-02-08
US20040051136A1 (en) 2004-03-18
DE10334819A1 (en) 2004-02-26
JP2004079577A (en) 2004-03-11

Similar Documents

Publication Publication Date Title
USRE43840E1 (en) Silicon carbide semiconductor device
US20210013336A1 (en) High-electron-mobility transistor (hemt) semiconductor devices with reduced dynamic resistance
US7170119B2 (en) Vertical type semiconductor device
US9136372B2 (en) Silicon carbide semiconductor device
US7407837B2 (en) Method of manufacturing silicon carbide semiconductor device
US7364971B2 (en) Method for manufacturing semiconductor device having super junction construction
JP5457017B2 (en) Transistor and MOSFET having A-side conductive channel and well region for trench protection, and method of forming transistor
JP4398185B2 (en) Vertical MOS transistor
JP2019102814A5 (en)
US20070241394A1 (en) Insulated Gate Semiconductor Device
JP2007027266A (en) Semiconductor element and its fabrication process
US10199457B2 (en) Silicon carbide semiconductor device
US20180097102A1 (en) Semiconductor device and method of manufacturing a semiconductor device
EP1936695B1 (en) Silicon carbide semiconductor device
KR102404463B1 (en) Silicon carbide power semiconductor device with folded channel region and manufacturing method thereof
KR20230128022A (en) mosfet device with undulating channel
JP4888341B2 (en) Silicon carbide semiconductor device
US10312362B2 (en) Switching element having inclined body layer surfaces
WO2021256117A1 (en) Semiconductor device
CN117637843A (en) Semiconductor device and method for manufacturing semiconductor device
CN115706167A (en) Semiconductor device and method of manufacturing semiconductor device
JP2019133980A (en) Semiconductor device and method of manufacturing semiconductor device

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

CC Certificate of correction
FPAY Fee payment

Year of fee payment: 12