Power MOSFET

• US 5,438,215 A
• Filed: 03/25/1994
• Issued: 08/01/1995
• Est. Priority Date: 03/25/1993
• Status: Expired due to Term

• Current Assignee: Infineon Technologies AG
• Original Assignee: Siemens AG
• Inventors: Tihanyi, Jenoe
• Primary Examiner(s): Limanek, Robert P.
• Assistant Examiner(s): Fahmy, Wael M.
• Application Number:
  US08/218,372
• Time in Patent Office: 494 Days
• Field of Search: 257/401, 257/139, 257/133, 257/149, 257/147, 257/155, 257/341, 257/138, 257/342, 257/355, 257/135
• US Class Current: 257/401
• CPC Class Codes: H01L 29/0634 Multiple reduced surface field (multi-RESURF) structures, e.g. double RESURF, charge compensation, cool, superjunction (SJ), 3D-RESURF, composite buffer (CB) structures
• CPC Class Codes: H01L 29/0878 Impurity concentration or distribution
• CPC Class Codes: H01L 29/1045 the doping structure being parallel to the channel length, e.g. DMOS like
• CPC Class Codes: H01L 29/7802 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7835 with asymmetrical source and drain regions, e.g. lateral high-voltage MISFETs with drain offset region, extended drain MISFETs

Abstract

A power MOSFET includes a semiconductor body having first and second surfaces. An inner zone of a first conduction type has a given dopant concentration. At least one base zone of a second conduction type is adjacent the inner zone and the first surface. At least one source zone is embedded in the at least one base zone. At least one drain zone is adjacent one of the surfaces. Additional zones of the second conduction type are disposed in the inner zone inside a space charge zone developing when a blocking voltage is present. At least one additional zone of the first conduction type is disposed between the additional zones of the second conduction type and is doped higher than the inner zone. The additional zones have a dopant level and the additional zones of the second conduction type are mutually spaced apart, for depleting charge carriers when a blocking voltage is applied.

Claims

1. A power MOSFET, comprising a semiconductor body having:

first and second surfaces;

an inner zone of a first conduction type and a given dopant concentration;

at least one base zone of a second conduction type being adjacent said inner zone and said first surface;

at least one source zone being embedded in said at least one base zone;

at least one drain zone adjacent one of said surfaces;

additional zones of the second conduction type being disposed in said inner zone inside a space charge zone developing when a blocking voltage is present; and

at least one additional zone of the first conduction type being disposed between said additional zones of the second conduction type and being doped higher than said inner zone;

said additional zones having a dopant level and said additional zones of the second conduction type being mutually spaced apart, for depleting charge carriers when a blocking voltage is applied.

2. The power MOSFET according to claim 1, wherein said at least one base zone and said drain zone are spaced apart by a shortest connecting line, and said additional zones have a flat shape and are disposed parallel to said shortest connecting line.

3. The power MOSFET according to claim 1, wherein said at least one base zone and said drain zone are spaced apart by a shortest connecting line, and said additional zones have a rod-like shape and are disposed parallel to said shortest connecting line.

4. The power MOSFET according to claim 3, wherein said drain zone adjoins said second surface, and said additional zones are disposed perpendicular to said surface.

5. The power MOSFET according to claim 3, wherein said drain zone adjoins said second surface, and said additional zones are disposed perpendicular to said surface.

6. The power MOSFET according to claim 2, wherein said drain zone and said additional zones are adjacent said first surface and are disposed parallel to said surface.

7. The power MOSFET according to claim 3, wherein said drain zone and said additional zones are adjacent said first surface and are disposed parallel to said surface.

8. The power MOSFET according to claim 1, wherein said additional zones of the second conductivity type are electrically connected to said at least one base zone.

9. The power MOSFET according to claim 1, wherein said at least one base zone is a plurality of base zones, and said at least one source zone is a plurality of source zones each being embedded in a respective one of said base zones.