Semiconductor device having a polycrystalline silicon IGFET

• US 9,917,160 B2
• Filed: 04/14/2016
• Issued: 03/13/2018
• Est. Priority Date: 08/07/2013
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Wood, Andrew Christopher Graeme, Blank, Oliver, Poelzl, Martin, Vielemeyer, Martin
• Primary Examiner(s): Soward, Ida M
• Application Number:
  US15/098,789
• Publication Number:
  US 20160233308A1
• Time in Patent Office: 698 Days
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/401 Multistep manufacturing processes
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/66666 Vertical transistors H01L29/66712, H01L29/66742 take precedence
• 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 29/7803 structurally associated with at least one other device assemblies H01L25/00; integrated circuits H01L27/00
• CPC Class Codes: H01L 29/7804 the other device being a pn-junction diode
• CPC Class Codes: H01L 29/7811 with an edge termination structure guard regions per se H01L29/0619; field plates per se H01L29/402
• 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 29/7827 Vertical transistors H01L29/7802, H01L29/78642 take precedence
• CPC Class Codes: H01L 29/8605 Resistors with PN junctions
• CPC Class Codes: H01L 29/861 Diodes
• CPC Class Codes: H10B 41/40 characterised by the peripheral circuit region

Abstract

A semiconductor device includes a semiconductor body, having a first surface, a gate electrode structure, which includes polycrystalline silicon, of an IGFET in a first trench extending from the first surface into the semiconductor body. The device also includes a semiconductor element, which is different from the gate electrode structure of the IGFET and includes polycrystalline silicon, in a second trench extending from the first surface into the semiconductor body, wherein the polycrystalline silicon of the IGFET and of the semiconductor element different therefrom ends below a top side of an insulation layer adjoining the first surface of the semiconductor body.

Claims

1. A semiconductor device comprising:

a semiconductor body, having a first surface,

a gate electrode structure, which comprises polycrystalline silicon, of an IGFET in a first trench extending from above the first surface into the semiconductor body, and

a semiconductor element, which is different from the gate electrode structure of the IGFET and comprises polycrystalline silicon, in a second trench extending from above the first surface into the semiconductor body, wherein the semiconductor element comprises a zap structure or an edge termination structure of the IGFET,

wherein the polycrystalline silicon of the IGFET and of the semiconductor element different therefrom ends below a top side of an insulation layer adjoining the first surface of the semiconductor body.

2. The semiconductor device as claimed in claim 1, wherein the first trench extends via a boundary of an active cell array into an edge termination structure of the IGFET.

3. The semiconductor device as claimed in claim 1, wherein any polycrystalline silicon of the semiconductor device ends below the surface of the insulation layer adjoining the first surface of the semiconductor body.

4. The semiconductor device as claimed in claim 1, wherein the polycrystalline silicon of the IGFET and of the semiconductor element different therefrom extends maximally as far as the first surface of the semiconductor body.

5. The semiconductor device as claimed in claim 1, wherein the gate electrode structure comprises a gate electrode and a gate electrode contact-making region, which is in contact with a conductive layer below the top side of the insulation layer adjoining the first surface of the semiconductor body.

6. The semiconductor device as claimed in claim 1, wherein the polycrystalline silicon of the gate electrode structure of the IGFET in the first trench has a planar top side.

7. The semiconductor device as claimed in claim 1, wherein the polycrystalline silicon in the first trench and in the second trench in each case has a planar top side, the horizontal extents of which are offset maximally by 100 nm with respect to one another.

8. The semiconductor device as claimed in claim 7, wherein the planar top sides lie in a common plane.

9. The semiconductor device as claimed in claim 1, wherein the first trench and the second trench have depths which deviate from one another maximally by 250 nm.

10. The semiconductor device as claimed in claim 9, wherein the first trench and the second trench have different widths.

11. The semiconductor device as claimed in claim 1, furthermore comprising a dielectric, which lines the walls of the first trench and of the second trench, in order to electrically insulate the polycrystalline silicon in the first trench and the second trench from the semiconductor body.