1. A semiconductor apparatus comprising:
a substrate;
a buffer layer formed on the substrate;
a strained layer superlattice buffer layer formed on the buffer layer;
an electron transit layer formed of a semiconductor material on the strained layer superlattice buffer layer; and
an electron supply layer formed of a semiconductor material on the electron transit layer;
the strained layer superlattice buffer layer being an alternate stack of first lattice layers including AlN and second lattice layers including GaN;
the strained layer superlattice buffer layer being doped with one, or two or more impurities selected from Fe, Mg and C.
2. A semiconductor apparatus comprising:
a substrate;
a buffer layer formed on the substrate;
a strained layer superlattice buffer layer formed on the buffer layer;
an electron transit layer formed of a semiconductor material on the strained layer superlattice buffer layer; and
an electron supply layer formed of a semiconductor material on the electron transit layer;
the strained layer superlattice buffer layer being an alternate stack of first lattice layers including AlN and second lattice layers including GaN;
either the first lattice layers or the second lattice layers being doped with one, or two or more impurities selected from Fe, Mg and C.
3. The semiconductor apparatus according to claim 2,
wherein the second lattice layers are doped with the impurity or impurities.
4. The semiconductor apparatus according to claim 1,
wherein a concentration of the impurity or impurities is 1\xd71018 cm\u22123 to 1\xd71020 cm\u22123.
5. The semiconductor apparatus according to claim 1,
wherein a relationship R>S is satisfied provided that a composition of the first lattice layers is AlRGa1-RN and a composition of the second lattice layers is AlSGa1-SN.
6. The semiconductor apparatus according to claim 1,
wherein the first lattice layers are formed of AlN, and the second lattice layers are formed of GaN.
7. The semiconductor apparatus according to claim 1,
wherein a thickness of the first lattice layer is not less than 0.5 nm and not more than 10 nm, and
a thickness of the second lattice layer is not less than 10 nm and not more than 40 nm.
8. The semiconductor apparatus according to claim 1,
wherein a ratio of a thickness of the second lattice layer to a thickness of the first lattice layer is not less than 4 and not more than 20.
9. The semiconductor apparatus according to claim 1,
wherein a thickness of the strained layer superlattice buffer layer is not less than 1000 nm and not more than 3000 nm.
10. The semiconductor apparatus according to claim 1,
wherein the buffer layer is formed of AlGaN.
11. The semiconductor apparatus according to claim 10,
wherein an Al composition in the buffer layer is not less than an effective Al composition in the strained layer superlattice buffer layer.
12. The semiconductor apparatus according to claim 1,
wherein the semiconductor apparatus further comprises a nucleation layer formed between the substrate and the buffer layer; and
the nucleation layer is formed of AlN.
13. The semiconductor apparatus according to claim 1,
wherein the substrate is a silicon substrate.
14. The semiconductor apparatus according to claim 1,
wherein the buffer layer, the strained layer superlattice buffer layer, the electron transit layer and the electron supply layer are layers formed by metal organic vapor phase epitaxy (MOVPE).
15. The semiconductor apparatus according to claim 1,
wherein the electron transit layer is formed of a material including GaN.
16. The semiconductor apparatus according to claim 1,
wherein the electron supply layer is formed of a material including AlGaN.
17. The semiconductor apparatus according to claim 1,
wherein the semiconductor apparatus further comprises a gate electrode, a source electrode and a drain electrode, the gate electrode, the source electrode and the drain electrode being formed on the electron supply layer.
18. The semiconductor apparatus according to claim 1,
wherein the semiconductor apparatus further comprises a cap layer formed on the electron supply layer; and
the cap layer is formed of a material including n-GaN.
19. A power supply unit comprising the semiconductor apparatus described in claim 1.
20. An amplifier comprising the semiconductor apparatus described in claim 1.
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 tee marker comprising:
a body including a display surface having a top end and a bottom end;
a bottom prehension member connected to the bottom end of the display surface, the display surface being in a generally vertical direction; and
a top prehension member connected to the top end of the display surface and movable relative to the bottom prehension member in the generally vertical direction, the top prehension member being telescopically mounted to the body for movement towards and away from the bottom prehension member in the generally vertical direction thereby providing for holding of display panels of variable height on the display surface of the tee marker between the top end and bottom prehension members.
2. The tee marker of claim 1, wherein the top prehension member is jaw shaped.
3. The tee marker of claim 1, further comprising a sliding channel fixedly connected to the body, the sliding channel receiving a shaft having the top prehension member at an upper end thereof, the top prehension member of the shaft being movable relative to the bottom prehension member by moving the shaft relative to the sliding channel.
4. The tee marker of claim 3, wherein the shaft and the sliding channel are disposed inside the body.
5. The tee marker of claim 1, wherein the body is hollow.
6. The tee marker of claim 1, wherein a thickness of the bottom end of the body is greater than a thickness of the top end of the body.
7. The tee marker of claim 1, wherein the display surface is a first display surface and the body includes a second display surface disposed on a side of the body opposite to the first display surface.
8. The tee marker of claim 1, further comprising a spike articulated to the bottom end of the body.
9. The tee marker of claim 8, wherein the body is hollow, the bottom end of the body is open, the bottom end of the body has a thickness greater than a thickness of the top end of the body so that the body is stackable onto a similar other tee marker; and
the spike is displaceable between an operational anchoring position in which the spike depends downwardly from the bottom end of the hollow body and a storage position in which the spike clears the open bottom end of the hollow body thereby allowing stacking onto the similar other tee marker.
10. The tee marker of claim 9, wherein the spike is moveably connected to the bottom end of the body between a stored position and an operating position, in the operating condition, the spike is disposed about a center of the bottom end of the body.
11. The tee marker of claim 9, wherein the spike is mounted onto an arm pivotally connected to the bottom end of the body, in the stored position, the arm is adjacent to a side of the bottom end of the body, and in the operating condition, the arm is at an angle with the side of the bottom end of the body.
12. The tee marker of claim 9, further comprising a locking mechanism locking the spike in the operating condition.
13. A tee marker comprising:
a body including a display surface having a top end and an open bottom end, the body being hollow, the bottom end of the body having a thickness greater than a thickness of the top end of the body so that the body is stackable onto a similar other tee marker; and
a spike articulated to the body, the spike being displaceable between an operational anchoring position in which the spike depends downwardly from the bottom end of the hollow body and a storage position in which the spike clears the open bottom end of the hollow body thereby allowing stacking onto the similar other tee marker.
14. The tee marker of claim 13, wherein in the operational anchoring condition, the spike is disposed about a center of the bottom end of the body.
15. The tee marker of claim 13, wherein the spike is mounted onto an arm pivotally connected to the bottom end of the body, in the storage position, the arm is adjacent to a side of the bottom end of the body, and in the operational anchoring condition, the arm is at an angle with the side of the bottom end of the body.
16. The tee marker of claim 13, further comprising a display surface on the body, the display surface having a top end and a bottom end, the display surface being in a generally vertical direction;
a bottom prehension member connected to the bottom end of the display surface; and
a top prehension member connected to the top end of the display surface and movable relative to the bottom prehension member in the generally vertical direction, the top prehension member being telescopically mounted to the body for movement towards and away from the bottom prehension member in the generally vertical direction thereby providing for holding of display panels of variable height on the display surface of the tee marker between the top end and bottom prehension members.
17. The tee marker of claim 16, further comprising a sliding channel fixedly connected to the body, the sliding channel receiving a shaft having the top prehension member at an upper end thereof, the top prehension member of the shaft being movable relative to the bottom prehension member by moving the shaft relative to the sliding channel.
18. The tee marker of claim 17, wherein the shaft and the sliding channel are disposed inside the body.
19. The tee marker of claim 16, wherein the top prehension member is jaw shaped.
20. The tee marker of claim 16, wherein the display surface is a first display surface and the body includes a second display surface disposed on a side of the body opposite to the first display surface.