Semiconductor device and manufacturing method thereof

• US 7,701,003 B2
• Filed: 12/14/2007
• Issued: 04/20/2010
• Est. Priority Date: 06/20/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Minato, Tadaharu, Takano, Kazutoyo
• Primary Examiner(s): Purvis; Sue
• Assistant Examiner(s): Tran; Tan N
• Application Number:
  US11/956,904
• Publication Number:
  US 20080315249A1
• Time in Patent Office: 858 Days
• Field of Search: 257/330, 257/331, 257/332, 257/334, 257/E27.091
• US Class Current: 257/330
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• 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 29/41766 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 29/456 on silicon
• CPC Class Codes: H01L 29/66348 with a recessed gate
• 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 29/7393 Insulated gate bipolar mode transistors, i.e. IGBT; IGT; COMFET
• CPC Class Codes: H01L 29/7396 with a non planar surface, e.g. with a non planar gate or with a trench or recess or pillar in the surface of the emitter, base or collector region for improving current density or short circuiting the emitter and base regions H01L29/7398 takes precedence
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT
• CPC Class Codes: H01L 29/7455 produced by an insulated gate structure
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A semiconductor substrate has a trench in a first main surface. An insulated gate field effect part includes a gate electrode formed in the first main surface. A potential fixing electrode fills the trench and has an expanding part expanding on the first main surface so that a width thereof is larger than the width of the trench. An emitter electrode is formed on the first main surface and insulated from the gate electrode electrically and connected to a whole upper surface of the expanding part of the potential fixing electrode. Thus, a semiconductor device capable of enhancing reliability in order to prevent an aluminum spike from generating and a manufacturing method thereof can be provided.

Claims

1. A semiconductor device comprising:

a semiconductor substrate having a first main surface and a trench in said first main surface;

an element having an insulated gate field effect part including a gate electrode formed in said first main surface;

a potential fixing electrode filling said trench and having an expanding part on said first main surface so that a width of the expanding part is larger than that of said trench; and

a first main electrode formed on said first main surface, electrically insulated from said gate electrode, and connected to an upper surface of said expanding part of said potential fixing electrode, said first main electrode comprising first metal films and a second metal film formed on said first metal films, said second metal film having a melting point lower than that of said first metal films, and said second metal film is formed of a material which more readily reacts with a material of said semiconductor substrate than a material of said first metal films.

2. The semiconductor device according to claim 1, wherein

said element is a bipolar transistor having said insulated gate field effect part.

3. The semiconductor device according to claim 1, wherein

said semiconductor substrate has a second main surface opposed to said first main surface,

said semiconductor device further comprises a second main electrode formed on said second main surface, and

said element is a vertical type element in which a main current flows between said first main electrode and said second main electrode.

4. The semiconductor device according to claim 1, wherein said second metal film is not in direct contact with the expanding part of the potential fixing electrode.