Semiconductor element

Abstract

A Schottky diode includes a substrate, a channel layer formed on the substrate and made of nitride-based compound semiconductor, an anode electrode and a cathode electrode which constitute an end portion of the current path of the semiconductor element, and a dummy electrode electrically connected to the substrate. The anode electrode is formed to have a Schottky barrier junction with the channel layer. The cathode layer is formed to have a low-resistance contact with the channel layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

These objects and other objects and advantages of the present invention will become more apparent upon reading of the following detailed description and the accompanying drawings in which:

FIG. 1 is a cross sectional diagram showing a structure of a Schottky diode as the first embodiment of the present invention;

FIG. 2 is a plan view of the Schottky diode of FIG. 1, as seen from the top;

FIG. 3 is a cross sectional diagram showing a state that a reverse bias is applied to the Schottky diode of FIG. 1;

FIG. 4 is a cross sectional diagram of the Schottky diode of FIG. 1, which is provided with a filter;

FIG. 5 is a cross sectional diagram showing a structure of a MESFET as the second embodiment of the present invention;

FIG. 6 is a cross sectional diagram showing a state that a reverse bias is applied to the MESFET of FIG. 5;

FIG. 7 is a diagram showing a modified example of the Schottky diode of the first embodiment; and

FIG. 8 is a diagram showing a modified example of the Schottky diode of the first embodiment.

Claims

1. A semiconductor element, comprising: a substrate;a channel layer formed on one principal surface of said substrate, and made of nitride-based compound semiconductor;first and second electrodes formed on said channel layer and constituting an end portion of a current path of said semiconductor element; anda dummy electrode formed on said channel layer and electrically connected to said substrate,wherein said first electrode is formed to have a Schottky barrier junction with said channel layer, andsaid second electrode is formed to have a low-resistance contact with said channel layer.

2. The semiconductor element according to claim 1, wherein said dummy electrode is formed to have a Schottky barrier junction with said channel layer or to have a MIS structure with said channel layer.

3. The semiconductor element according to claim 1, wherein said dummy electrode is formed between said first electrode and said second electrode.

4. The semiconductor element according to claim 1, wherein said dummy electrode is formed to surround either one of said first electrode and said second electrode, when it is seen from above the one principal surface of said substrate.

5. The semiconductor element according to claim 1, wherein said substrate is an insulating substrate.

6. The semiconductor element according to claim 1, further comprising a frame having conductivity, formed on the other principal surface of said substrate or on an exposed portion of the one principal surface of said substrate on which said channel layer is not formed,wherein said frame and said dummy electrode are electrically connected to each other.

7. A semiconductor element, comprising: a substrate;a channel layer formed on one principal surface of said substrate and made of nitride-based compound semiconductor;a first electrode formed on said channel layer, for controlling a current path of said semiconductor element;a second electrode formed on said channel layer, for functioning as a drain electrode;a third electrode formed on said channel layer, for functioning as a source electrode; anda dummy electrode formed on said channel layer and electrically connected to said substrate.

8. The semiconductor element according to claim 7, wherein said first electrode is formed to have a Schottky barrier junction with said channel layer or to have a MIS structure with said channel layer, and said second electrode is formed to have a low-resistance contact with said channel layer.

9. The semiconductor element according to claim 7, wherein said dummy electrode is formed to have a Schottky barrier junction with said channel layer or to have a MIS structure with said channel layer.

10. The semiconductor element according to claim 7, wherein said dummy electrode is formed between said first electrode and said second electrode.

11. The semiconductor element according to claim 7, wherein said dummy electrode is formed to surround either one of said first electrode and said second electrode, when it is seen from above the one principal surface of said substrate.

12. The semiconductor element according to claim 7, wherein said substrate is an insulating substrate.

13. The semiconductor element according to claim 7, further comprising a frame having conductivity, formed on the other principal surface of said substrate or on an exposed portion of the one principal surface of said substrate on which said channel layer is not formed,wherein said frame and said dummy electrode are electrically connected to each other.