Field effect-controllable semiconductor component

• US 5,973,360 A
• Filed: 09/21/1998
• Issued: 10/26/1999
• Est. Priority Date: 03/20/1996
• Status: Expired due to Term

• Current Assignee: Infineon Technologies AG
• Original Assignee: Siemens AG
• Inventors: Tihanyi, Jenoe
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): Nadav, Ori
• Application Number:
  US09/157,704
• Time in Patent Office: 400 Days
• Field of Search: 257/329-334, 257/401, 438/268-274
• US Class Current: 257/330
• 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 29/0653 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 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41766 with at least part of the source or drain electrode having contact below the semiconductor surface, e.g. the source or drain electrode formed at least partially in a groove or with inclusions of conductor inside the semiconductor H01L29/41733 - H01L29/41758 take precedence
• 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 29/7802 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

Abstract

The field effect-controllable semiconductor component has a drain zone of the first conductivity type and also at least one gate electrode which is composed of polycrystalline silicon and is insulated from the drain zone. A source region of the second conductivity type is introduced in the drain zone. In addition, there is formed in the drain zone a trench structure, which reach from the surface of the epitaxial layer down into the substrate layer. An additional field plate made of polysilicon and embedded in an oxide layer is introduced in the trench structure. The thickness of the oxide surrounding the field plate increases down in a direction towards the drain.

Claims

1. A field effect-controllable semiconductor component, comprising:

a semiconductor body having a surface;

a drain zone of a first conductivity type in said semiconductor body;

a gate electrode composed of polycrystalline silicon in said semiconductor body, said gate electrode being insulated from said drain zone;

a source region of a second conductivity type introduced in said drain zone;

said drain zone having a trench structure formed therein reaching from said surface of said semiconductor body into said drain zone; and

a field plate in said trench structure and an oxide layer surrounding said field plate, said oxide layer having a thickness increasing gradually and continuously from said surface in a direction towards said drain zone.

2. The semiconductor component according to claim 1, which further comprises a further layer surrounding said oxide layer, said further layer being doped more heavily with the first conductivity type than said drain zone.

3. The semiconductor component according to claim 2, which further comprises at least one additional layer of the second conductivity type introduced into said oxide layer surrounding said field plate.

4. The semiconductor component according to claim 1, wherein said trench structure is one of a multiplicity of trench structures arranged in grid form in said semiconductor body.

5. The semiconductor component according to claim 1, wherein said trench structure is one of a multiplicity of trench structures arranged in strip form in said semiconductor body.

6. The semiconductor component according to claim 1, wherein said field plate is electrically connected to a source terminal of said source region.

7. The semiconductor component according to claim 1, wherein said field plate is electrically connected to said gate electrode.

8. The semiconductor component according to claim 7, wherein said field plate is a vertical field plate serving as a gate.

9. The semiconductor component according to claim 1, wherein said field plate is composed of polysilicon.

10. The semiconductor component according to claim 1, wherein said field plate is composed of polysilicon.