1. A semiconductor device, comprising:
a first nitride semiconductor layer;
a second nitride semiconductor layer provided on the first nitride semiconductor layer, a bandgap of the second nitride semiconductor layer being not less than a bandgap of the first nitride semiconductor layer;
a first electrode provided on the second nitride semiconductor layer;
a second electrode provided on the second nitride semiconductor layer and separated from the first electrode;
a first insulating film provided on the second nitride semiconductor layer;
a first control electrode provided on the first insulating film between the first electrode and the second electrode, the first control electrode including
a first edge, and
a second edge separated from the first edge,
a distance between the first control electrode and the first electrode being shorter than a distance between the first control electrode and the second electrode,
the first edge being provided between the second edge and the first electrode in a first direction from the first electrode toward the second electrode;
a second insulating film provided between the first control electrode and the first electrode and between the first control electrode and the second electrode; and
a conductor provided on the second insulating film, the conductor including
a first portion having a first length in the first direction, and
a third edge positioned between the first portion and the first electrode in the first direction,
an electric field strength at a first region being substantially equal to an electric field strength at a second region, the first region overlapping the first edge when projected onto a plane perpendicular to a second direction from the first nitride semiconductor layer toward the second nitride semiconductor layer, the second region overlapping the third edge when projected onto the plane.
2. The device according to claim 1, wherein
a first capacitance is formed between the first control electrode and the second nitride semiconductor layer,
a second capacitance is formed between the conductor and the second nitride semiconductor layer, and
a total of the first capacitance and the second capacitance is not less than 1.1 times and not more than 1.4 times the first capacitance.
3. A semiconductor device, comprising:
a first nitride semiconductor layer;
a second nitride semiconductor layer provided on the first nitride semiconductor layer, a bandgap of the second nitride semiconductor layer being not less than a bandgap of the first nitride semiconductor layer;
a first electrode provided on the second nitride semiconductor layer;
a second electrode provided on the second nitride semiconductor layer and separated from the first electrode;
a first insulating film provided on the second nitride semiconductor layer;
a first control electrode provided on the first insulating film between the first electrode and the second electrode, the first control electrode including
a first edge, and
a second edge separated from the first edge,
a first capacitance being formed between the first control electrode and the second nitride semiconductor layer,
a distance between the first control electrode and the first electrode being shorter than a distance between the first control electrode and the second electrode,
the first edge being provided between the second edge and the first electrode in a first direction from the first electrode toward the second electrode;
a second insulating film provided between the first control electrode and the first electrode and between the first control electrode and the second electrode; and,
a conductor provided on the second insulating film, the conductor including a first portion having a first length in the first direction, a second capacitance being formed between the conductor and the second nitride semiconductor layer, a total of the first capacitance and the second capacitance being not less than 1.1 times and not more than 1.4 times the first capacitance.
4. The device according to claim 1, wherein the conductor includes a second portion having a second length in a direction from the first control electrode toward the second electrode.
5. The device according to claim 1, wherein a film thickness of the second insulating film is 100 nanometers or more.
6. The device according to claim 1, wherein the first length is 2 micrometers or less.
7. The device according to claim 4, wherein the first length is shorter than the second length.
8. The device according to claim 1, wherein
the first nitride semiconductor layer includes AlwGa1-w-xInxN (0\u2266w<1, 0\u2266x\u22661, and 0\u2266w+x\u22661), and
the second nitride semiconductor layer includes AlyGa1-y-zInzN (0<y\u22661, 0\u2266z<1, and 0\u2266y+z\u22661).
9. The device according to claim 1, wherein the first insulating film further includes a portion provided between the first control electrode and the second insulating film.
10. The device according to claim 1, wherein the first insulating film includes one selected from the group consisting of SiO2, Si3N4, and Al2O3.
11. The device according to claim 1, wherein the second insulating film includes one selected from the group consisting of SiN, SiON, and SiO2.
12. The device according to claim 1, further comprising a substrate,
the first nitride semiconductor layer being provided on the substrate.
13. The device according to claim 12, wherein the substrate includes one selected from the group consisting of silicon, sapphire, silicon carbide, gallium nitride, aluminum nitride, and gallium oxide.
14. The device according to claim 12, further comprising an intermediate layer provided between the substrate and the first nitride semiconductor layer.
15. The device according to claim 1, wherein a thickness of the first nitride semiconductor layer is not less than 0.1 micrometers and not more than 10 micrometers.
16. The device according to claim 1, wherein a thickness of the second nitride semiconductor layer is not less than 1 nanometer and not more than 50 nanometers.
17. A semiconductor device, comprising:
a first semiconductor device; and
a second semiconductor device,
the first semiconductor device including a first nitride semiconductor layer, a second nitride semiconductor layer provided on the first nitride semiconductor layer, a first electrode provided on the second nitride semiconductor layer, a second electrode provided on the second nitride semiconductor layer and separated from the first electrode, a first insulating film provided on the second nitride semiconductor layer, a first control electrode provided on the first insulating film between the first electrode and the second electrode, a second insulating film provided between the first control electrode and the first electrode and between the first control electrode and the second electrode, and a conductor provided on the second insulating film, a bandgap of the second nitride semiconductor layer being not less than a bandgap of the first nitride semiconductor layer, the first control electrode including a first edge and a second edge, the second edge being separated from the first edge, a distance between the first control electrode and the first electrode being shorter than a distance between the first control electrode and the second electrode, the first edge being provided between the second edge and the first electrode in a first direction from the first electrode toward the second electrode, the conductor including a first portion and a third edge, the first portion having a first length in the first direction, the third edge being positioned between the first portion and the first electrode in the first direction, an electric field strength at a first region being substantially equal to an electric field strength at a second region, the first region overlapping the first edge when projected onto a plane perpendicular to a second direction from the first nitride semiconductor layer toward the second nitride semiconductor layer, the second region overlapping the third edge when projected onto the plane,
the second semiconductor device including a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type, a third semiconductor region of the second conductivity type, a third electrode, a fourth electrode, a third insulating film provided on the first semiconductor region, and a second control electrode provided on the third insulating film, the second semiconductor region being provided at the first semiconductor region, the third semiconductor region being provided at the first semiconductor region and separated from the second semiconductor region, the third electrode being electrically connected to the second semiconductor region and electrically connected to the first control electrode, the fourth electrode being electrically connected to the third semiconductor region and electrically connected to the first electrode.
18. The semiconductor device according to claim 17, wherein
a first capacitance is formed between the first control electrode and the second nitride semiconductor layer,
a second capacitance is formed between the conductor and the second nitride semiconductor layer, and
a total of a first capacitance and a second capacitance is not less than 1.1 times and not more than 1.4 times the first capacitance.
19. The semiconductor device according to claim 17, wherein
the first semiconductor region includes silicon,
the second semiconductor region includes silicon; and
the third semiconductor region includes silicon.
20. A semiconductor device, comprising:
a first semiconductor device; and
a second semiconductor device,
the first semiconductor device including a first nitride semiconductor layer, a second nitride semiconductor layer provided on the first nitride semiconductor layer, a first electrode provided on the second nitride semiconductor layer, a second electrode provided on the second nitride semiconductor layer and separated from the first electrode, a first insulating film provided on the second nitride semiconductor layer, a first control electrode provided on the first insulating film between the first electrode and the second electrode, a second insulating film provided between the first control electrode and the first electrode and between the first control electrode and the second electrode, and a conductor provided on the second insulating film, a bandgap of the second nitride semiconductor layer being not less than a bandgap of the first nitride semiconductor layer, the first control electrode including a first edge and a second edge, the second edge being separated from the first edge, a first capacitance being formed between the first control electrode and the second nitride semiconductor layer, a distance between the first control electrode and the first electrode being shorter than a distance between the first control electrode and the second electrode, the first edge being provided between the second edge and the first electrode in a first direction from the first electrode toward the second electrode, the conductor including a first portion having a first length in the first direction, a second capacitance being formed between the conductor and the second nitride semiconductor layer, a total of the first capacitance and the second capacitance being not less than 1.1 times and not more than 1.4 times the first capacitance,
the second semiconductor device including a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type, a third semiconductor region of the second conductivity type, a third electrode, a fourth electrode, a third insulating film provided on the first semiconductor region, and a second control electrode provided on the third insulating film, the second semiconductor region being provided at the first semiconductor region, the third semiconductor region being provided at the first semiconductor region and separated from the second semiconductor region, the third electrode being electrically connected to the second semiconductor region and electrically connected to the first control electrode, the fourth electrode being electrically connected to the third semiconductor region and electrically connected to the first electrode.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A shell main body for muffler, wherein the shell main body is made of one rolled flat plate and a joint portion of the plate is welded, the shell main body comprising:
an inner shell formed by a part of the plate to have a cylindrical shape with a cross section that is not a perfect circle but is defined by small arc portions alternating with large arc portions; and
an outer shell formed by another part of the plate that continues from a portion of the inner shell to wrap an outer surface of the inner shell and having a cylindrical shape with a cross section that is not a perfect circle but is defined by small arc portions alternating with large arc portions,
wherein the small arc portions of the inner shell are in close contact with the small arc portions of the outer shell;
wherein the large arc portions of the inner and outer shells form a gap therebetween having an upper gap and a lower gap at an upper side and a lower side thereof, respectively;
wherein at least one of the inner shell and the outer shell is provided with at least one radially projecting bead that extends continuously in a circumferential direction along the small arc portions of the at least one of the inner and outer shells to define a passage inside of the radially projecting bead so that the passage can allow the upper gap and the lower gap to communicate with each other; and
wherein the outer shell is provided on an upper surface side thereof with a communicating path allowing the upper gap and an outside of the outer shell to communicate with each other.
2. The shell main body according to claim 1, wherein the communicating path is formed by a gap that is formed between the inner shell and the outer shell and in places excluding welded portions of the inner shell and the outer shell.
3. The shell main body according to claim 2, wherein the at least one radially projecting bead comprises a plurality of radially projecting beads formed along each of the small arc portions of the at least one of the inner shell and the outer shell, and wherein the plurality of radially projecting beads are arranged in an axial direction of the shell main body at intervals.
4. The shell main body according to claim 1, wherein the at least one radially projecting bead comprises a plurality of radially projecting beads formed along each of the small arc portions of the at least one of the inner shell and the outer shell, and wherein the plurality of radially projecting beads are arranged in an axial direction of the shell main body at intervals.
5. A shell main body for a muffler, wherein the shell main body is made of one rolled flat plate and a joint portion of the plate is welded, the shell main body comprising:
an inner shell formed by a part of the plate to have a cylindrical shape with a cross section that is not a perfect circle but is defined by small arc portions alternating with large arc portions; and
an outer shell formed by another part of the plate that continues from a portion of the inner shell to wrap an outer surface of the inner shell and having a cylindrical shape with a cross section that is not a perfect circle but is defined by small arc portions alternating with large arc portions,
wherein the small arc portions of the inner shell are in close contact with the small arc portions of the outer shell;
wherein the large arc portions of the inner and outer shells form a gap therebetween having an upper gap and a lower gap at an upper side and a lower side thereof, respectively;
wherein at least one of the inner shell and the outer shell is provided with at least one radially projecting bead that extends continuously in a circumferential direction along the small arc portions of the at least one of the inner and outer shells to space the inner shell and the outer shell from each other and define a passage formed on both sides of the radially projecting bead so that the passage can allow the upper gap and the lower gap to communicate with each other; and
wherein the outer shell is provided on an upper surface side thereof with a communicating path allowing the upper gap and an outside of the outer shell to communicate with each other.
6. The shell main body according to claim 5, wherein the communicating path is formed by a gap that is formed between the inner shell and the outer shell and in places excluding welded portions of the inner shell and the outer shell.
7. The shell main body according to claim 6, wherein the at least one radially projecting bead comprises a plurality of radially projecting beads formed along each of the small arc portions of the at least one of the inner shell and the outer shell, and wherein the plurality of radially projecting beads are arranged in an axial direction of the shell main body at intervals.
8. The shell main body according to claim 5, wherein the at least one radially projecting bead comprises a plurality of radially projecting beads formed along each of the small arc portions of the at least one of the inner shell and the outer shell, and wherein the plurality of radially projecting beads are arranged in an axial direction of the shell main body at intervals.