# US 8,785,970 B2 · HF-controlled bidirectional switch

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- Number: US 8,785,970 B2
- Document ID: US8785970B2
- Status: Granted
- Kind: B2
- Application number: 13/104,254
- Filed: 2011-05-10
- Published: 2011-11-24
- Granted: 2014-07-22
- Earliest claimed: 2010-05-18
- Assignees: STMicroelectronics (Tours) SAS
- Applicants: Samuel Menard
- Inventors: Samuel Menard
- Web page: https://patentgrep.com/patent/US8785970B2

## CPC

- H10D 18/80: Bidirectional devices, e.g. triacs
- H10D 8/60: Schottky-barrier diodes
- H10D 18/021: {of bidirectional devices, e.g. triacs}
- H10D 62/192: {Base regions of thyristors}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A bidirectional switch controllable by a voltage between its gate and rear electrode and including an N-type semiconductor substrate surrounded with a P-type well; on the front surface side, a P-type well in which is formed a first N-type region; on the rear surface side, a P-type layer in which is formed a second N-type region. The well is doped to less than 1016 at./cm3, the exposed surfaces of this well being heavily P-type doped. At least a third P-type region, of same doping level as the well, is formed on the front surface side in the substrate, and contains at least a fourth N-type region of a doping level lower than 1017 at./cm3, on which is formed a Schottky contact.

## Claims

### Claim 1

A bidirectional switch comprising, on its rear surface, a first main electrode (A1 ) and, on its front surface, a second main electrode (A2 ) and a gate electrode (G), this switch being controllable by a voltage between the gate and the first electrode, and comprising:
a semiconductor substrate of a first conductivity type surrounded with a wall of the second conductivity type;
on the front surface side, a well of the second conductivity type in substantially half of which is formed a first region of the first conductivity type;
on the rear surface side, a layer of the second conductivity type in which is formed a second region of the first conductivity type substantially in front of a portion of said well which is not taken up by the first region;
wherein said well and said layer are doped with a doping level lower than 1016 at./cm3, the exposed external surfaces of said well and of said layer being heavily doped of the second conductivity type; and
wherein at least a third region of the second conductivity type, of same doping level as said well and said layer, is formed on the front surface side in the substrate, the third region containing at least one fourth region of the first conductivity type of a doping level lower than 1017 at./cm3, on which is formed a Schottky contact.

### Claim 2 (depends on 1)

The bidirectional switch of claim 1, wherein each fourth region further includes at least one heavily-doped contact area of the first conductivity type.

### Claim 3 (depends on 1)

The bidirectional switch of claim 1, wherein a gate region of the first conductivity type is formed in a portion of the third region arranged in contact with said wall.

### Claim 4 (depends on 3)

The bidirectional switch of claim 3, comprising, on the rear surface side, under the gate area, means for channeling the gate current towards the center of the component.

### Claim 5 (depends on 3)

The bidirectional switch of claim 3, wherein a metallization connects the Schottky contact areas and the gate contact area.

### Claim 6 (depends on 5)

The bidirectional switch of claim 5, wherein said metallization extends above the wall and/or a region of the second conductivity type in contact with the wall to form a capacitor.

### Claim 7 (depends on 1)

The bidirectional switch of claim 1, wherein the first conductivity type is type N.