High-voltage vertical transistor with a multi-layered extended drain structure

• US 7,829,944 B2
• Filed: 08/30/2004
• Issued: 11/09/2010
• Est. Priority Date: 09/07/2001
• Status: Expired due to Fees

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Power Integrations Incorporated
• Inventors: Disney, Donald Ray
• Primary Examiner(s): Mondt; Johannes P
• Application Number:
  US10/929,590
• Publication Number:
  US 20050023571A1
• Time in Patent Office: 2,262 Days
• Field of Search: 257328-331, 257339-342
• US Class Current: 257/331
• CPC Class Codes: H01L 29/0653 adjoining the input or output region of a field-effect device, e.g. the source or drain region
• CPC Class Codes: H01L 29/0878 Impurity concentration or distribution
• CPC Class Codes: H01L 29/402 Field plates
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41741 for vertical or pseudo-vertical devices
• CPC Class Codes: H01L 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• CPC Class Codes: H01L 29/7802 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/7824 with a substrate comprising an insulating layer, e.g. SOI-LDMOS transistors
• CPC Class Codes: H01L 29/7825 with trench gate electrode trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/7828 without inversion channel, e.g. vertical ACCUFETs, normally-on vertical MISFETs

Abstract

A high-voltage transistor with a low specific on-state resistance and that supports high voltage in the off-state includes one or more source regions disposed adjacent to a multi-layered extended drain structure which comprises extended drift regions separated from field plate members by one or more dielectric layers. With the field plate members at the lowest circuit potential, the transistor supports high voltages applied to the drain in the off-state. The layered structure may be fabricated in a variety of orientations. A MOSFET structure may be incorporated into the device adjacent to the source region, or, alternatively, the MOSFET structure may be omitted to produce a high-voltage transistor structure having a stand-alone drift region.

Claims

1. A vertical high-voltage transistor comprising:

a substrate of a first conductivity type;

a pair of first trenches in the substrate that define a mesa;

a field plate disposed in each first trench of the pair of first trenches, the field plate being separated from the mesa by a dielectric layer;

a second trench in the dielectric layer;

an insulated gate disposed in the second trench between the mesa and the field plate member.

2. The vertical high-voltage transistor according to claim 1 wherein a drift region of the first conductivity type extends in the mesa in a vertical direction.

3. The vertical high-voltage transistor according to claim 2 further comprising:

a body region of a second conductivity type adjoining the drift region in the mesa.

4. The vertical high-voltage transistor according to claim 1 wherein a width of the mesa is less than a height of the mesa.

5. A vertical high-voltage transistor comprising:

first and second trenches that define a mesa having first and second sidewalls in a semiconductor substrate, the first and second trenches being filled with a dielectric material that covers the first and second sidewalls;

first and second field plates disposed in the dielectric material of the first and second trenches, respectively, the first and second field plates being respectively insulated from the first and second sidewalls of the mesa in a lateral direction, and insulated from the semiconductor substrate in a vertical direction, by the dielectric material;

first and second gate members disposed in the dielectric material between the first and second sidewalls of the mesa, and the first and second field plates, respectively.

6. The vertical high-voltage transistor according to claim 5 wherein the first and second field plates extend from a top surface of the semiconductor substrate.

7. A vertical high-voltage transistor comprising:

first and second trenches that define a mesa having first and second sidewalls in a semiconductor substrate, the mesa having a height and a width, the height being greater than the width, the first and second trenches being filled with a dielectric material that covers the first and second sidewalls;

first and second field plates disposed in the dielectric material of the first and second trenches, respectively, the first and second field plates extending from a top surface of the semiconductor substrate to a vertical depth that is substantially the same as the height of the mesa, each of the first and second field plates being respectively insulated from the first and second sidewalls of the mesa in a lateral direction, and insulated from the semiconductor substrate in a vertical direction, by the dielectric material;

a trench gate structure that includes first and second gate members disposed in the dielectric material between the first and second sidewalls of the mesa, and the first and second field plates, respectively.

8. A vertical high-voltage transistor comprising:

first and second trenches that define a mesa having first and second sidewalls in a semiconductor substrate, the mesa having a height and a width, the height being at least five times greater than the width, the first and second trenches being filled with a dielectric material that covers the first and second sidewalls;

first and second field plates disposed in the dielectric material of the first and second trenches, respectively, the first and second field plates extending from a top surface of the semiconductor substrate to a vertical depth that is substantially the same as the height of the mesa, each of the first and second field plates being respectively insulated from the first and second sidewalls of the mesa in a lateral direction, and insulated from the semiconductor substrate in a vertical direction, by the dielectric material;

a trench gate structure that includes first and second gate members disposed in the dielectric material between the first and second sidewalls of the mesa, and the first and second field plates, respectively.

9. A vertical high-voltage transistor comprising:

a mesa of semiconductor material having first and second sidewalls

a dielectric material that covers the first and second sidewalls;

first and second field plates disposed substantially parallel to the first and second sidewalls, respectively, the first and second field plates being respectively insulated from the first and second sidewalls of the mesa in a lateral direction, and insulated from the semiconductor substrate in a vertical direction, by the dielectric material;

first and second gate members disposed in the dielectric material between the first and second sidewalls of the mesa, and the first and second field plates, respectively.

10. A vertical high-voltage transistor comprising:

first and second trenches that define a mesa having first and second sidewalls in a semiconductor substrate, the mesa having a height and a width, the height being at least five times greater than the width, the first and second sidewalls being covered with a dielectric material having a lateral thickness of at least two microns;

first and second field plates disposed in the first and second trenches, respectively, the first and second field plates extending from a top surface of the semiconductor substrate to a vertical depth that is substantially the same as the height of the mesa, each of the first and second field plates being respectively insulated from the first and second sidewalls of the mesa by the dielectric material, the first and second field plates also being insulated from the substrate;

a trench gate structure that includes first and second gate members disposed in the dielectric material between the first and second sidewalls of the mesa and the first and second field plates, respectively.

11. The vertical high-voltage transistor according to claim 10 wherein a drift region of a first conductivity type extends in the mesa in a vertical direction.

12. The vertical high-voltage transistor according to claim 11 further comprising:

a body region of a second conductivity type adjoining the drift region in the mesa, the body region being disposed adjacent the first and second gate members.