What is claimed is:
1. A semiconductor device including a source electrode and a drain electrode between which a gate electrode is provided, comprising:
a channel layer made of a semiconductor as a current path between the source electrode and the drain electrode and
a first barrier layer formed between the channel layer and the gate electrode and made of a semiconductor whose electron affinity is smaller than that of the semiconductor forming the channel layer, including a p-type low resistivity region with a high concentration of p-type impurity provided in correspondence with the gate electrode and a high resistivity region with a low concentration of impurity.
2. A semiconductor device according to claim 1 wherein the p-type low resistivity region in the first barrier layer is buried in the high resistivity region.
3. A semiconductor device according to claim 1 wherein a p-type impurity concentration in the p-type low resistivity region in the first barrier layer is 11018 cm3 or above.
4. A semiconductor device according to claim 1 wherein an impurity concentration in the high resistivity region in the first barrier layer is 21017 cm3 or below and resistivity of the high resistivity region is 1102 ohm-cm or above.
5. A semiconductor device according to claim 1 wherein the first barrier layer further includes a carrier supply region with n-type impurity.
6. A semiconductor device according to claim 1 wherein the first barrier layer is made of AlGaAs that is a group III-V compound semiconductor and the channel layer is made of InGaAs that is a group III-V compound semiconductor.
7. A semiconductor device according to claim 6 wherein aluminum mole fraction is 0.25 or below in the AlGaAs forming the first barrier layer.
8. A semiconductor device according to claim 6 wherein indium mole fraction is 0.1 or above in the InGaAs forming the channel layer.
9. A semiconductor device according to claim 6 wherein the p-type low resistivity region in the first barrier layer is formed through diffusion of zinc as p-type impurity.
10. A semiconductor device according to claim 1 further comprising a second barrier layer placed on a side of the channel layer opposite to the first barrier layer and made of a semiconductor whose electron affinity is smaller than that of the semiconductor forming the channel layer.
11. A semiconductor device according to claim 10 wherein the second barrier layer includes a carrier supply region with n-type impurity at least in part of the second barrier layer.
12. A semiconductor device according to claim 10 wherein the first and second barrier layers are each made of AlGaAs that is a group III-V compound semiconductor and the channel layer is made of InGaAs that is a group III-V compound semiconductor.
13. A semiconductor device according to claim 1 further comprising a third barrier layer placed between the channel layer and the first barrier layer and made of a semiconductor whose electron affinity is smaller than that of the semiconductor forming the first barrier layer.
14. A semiconductor device according to claim 13 wherein the third barrier layer includes a carrier supply region with n-type impurity at least in part of the third barrier layer.
15. A semiconductor device according to claim 13 wherein the first barrier layer is made of GaAs that is a group III-V compound semiconductor, the channel layer is made of InGaAs that is a group III-V compound semiconductor, and the third barrier layer is made of AlGaAs that is a group III-V compound semiconductor.
16. A semiconductor device according to claim 15 wherein the p-type low resistivity region in the first barrier layer is formed through diffusion of zinc as p-type impurity.
17. A semiconductor device according to claim 1 wherein the channel layer includes n-type impurity.
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 connecting element for a mechanical and electrically conductive connection, comprising:
an operating element having first and second plates which are directed toward one another such that two conically tapering faces are arranged on respective opposite sides of the first and second plates, thereby forming two conically tapering openings with cone openings directed opposite to one another;
first and second wedges respectively inserted in the two cone openings, wherein the first and second wedges can be displaced with respect to each other such that faces of the wedges drive the conical tapering faces of the first and second plates away from one another;
a supporting wall, with at least one of the first and second plates supported against the supporting wall by a tensioning loop; and
the tensioning loop passing through the supporting wall, wherein when the first and second wedges are displaced with respect to each other driving the conical tapering faces of the first and second plates away from one another, the tensioning loop is tensioned.
2. The connecting element of claim 1, wherein the first and second wedges are displaced with respect to each other by a screw.
3. The connecting element of claim 1, wherein the connecting element has at least one first and at least one second spreading element, which each have an associated first and second electrical conductor.
4. A connecting element for a mechanical and electrically conductive connection, comprising:
an electrical conductor, which has a cutout in its outer contour in which at least one spreading element of the connecting element can be inserted;
an operating element having first and second plates which are directed toward one another such that two conically tapering faces are arranged on respective opposite sides of the first and second plates, thereby forming two conically tapering openings with cone openings directed opposite to one another;
first and second wedges respectively inserted in the two cone openings, wherein the first and second wedges can be displaced with respect to each other such that faces of the wedges drive the conical tapering faces of the first and second plates away from one another;
a supporting wall arranged in a central region of the connecting element;
a truncated cone supported against the supporting wall; and
a tensioning loop passing through the truncated cone and the supporting wall, wherein when the first and second wedges are displaced with respect to each other driving the conical tapering faces of the first and second plates away from one another, the tensioning loop is tensioned and the truncated cone is drawn into a conical opening in the at least on spreading element.
5. The connecting element of claim 4, wherein the electrical conductor is an inner conductor of a compressed gas-insulated tubular conductor.