Trench MOSFET with trench termination and manufacture thereof

• US 7,750,398 B2
• Filed: 09/26/2007
• Issued: 07/06/2010
• Est. Priority Date: 09/26/2006
• Status: Expired due to Fees

• Current Assignee: Force Mos Technology Co., Ltd.
• Original Assignee: Force-Mos Technology Corporation (Force Mos Technology Co., Ltd.)
• Inventors: Hshieh, Fwu-Iuan
• Primary Examiner(s): Tran; Minh-Loan T
• Assistant Examiner(s): Sengdara; Vongsavanh
• Application Number:
  US11/862,064
• Publication Number:
  US 20090057756A1
• Time in Patent Office: 1,014 Days
• Field of Search: 257/328, 257/329, 257/330, 257/331, 257/491, 257/E29.201, 257/E29.257, 257/E29.26
• US Class Current: 257/330
• CPC Class Codes: H01L 29/0623 Buried supplementary region, e.g. buried guard ring multi-RESURF H01L29/0634
• CPC Class Codes: H01L 29/0661 specially adapted for altering the breakdown voltage by removing semiconductor material at, or in the neighbourhood of, a reverse biased junction, e.g. by bevelling, moat etching, depletion etching
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• 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 29/7811 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 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A trench MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) with a trench termination, including a substrate including a drain region which is strongly doped and a doping epi layer region, which is weekly doped the same type as the drain region, on the drain region; a plurality of source and body regions formed in the epi layer; a metal layer including a plurality of metal layer regions which are connected to respective source and body, and gate regions forming metal connections of the MOSFET; a plurality of metal contact plugs connected to respective metal layer regions; a plurality of gate trenches filled with polysilicon to form a plurality of trenched gates on top of epi layer; an insulating layer deposited on the epi layer formed underneath the metal layer with a plurality of metal contact holes therein for contacting respective source and body regions; a margin terminating gate trench which is around the gate trenches; and a margin terminating active region which is formed underneath the margin terminating gate trench.

Claims

1. A trenched MOSFET with a trench termination, comprising:

a substrate comprising a drain region which is strongly doped and a doping epi layer region, which is weakly doped the same type as the drain region, on the drain region;

a plurality of body regions with opposite type doping of said epi layer region served as channel regions disposed in said epi layer region;

a plurality of source regions with same type doping as said drain region formed in said body regions;

a metal layer comprising a plurality of metal layer regions which are connected to respective said source and body regions, and gate regions forming source metal and gate metal connections of the MOSFET;

a plurality of metal contact plugs connected to respective said source and gate metals;

a plurality of gate trenches filled with polysilicon to form a plurality of trenched gates in top portion of said epi layer;

an insulating layer deposited on said epi layer formed underneath said metal layers with a plurality of metal contact holes therein for contacting respective said source and body regions;

a margin terminating gate trench formed in a termination area;

a margin terminating trench gate formed along trench sidewall of said margin termination trench;

a first margin terminating doping region comprising source and body regions formed along one trench sidewall of said margin terminating trench gate; and

a second margin terminating doping region comprising said source and body regions, formed underneath a portion of trench bottom of said margin terminating gate trench near by bottom of another trench sidewall of said margin terminating trench gate.

2. The trench MOSFET as claimed in claim 1, wherein said second margin terminating doping region has overlap with trench bottom of said margin terminating trench gate.

3. The trench MOSFET as claimed in claim 1, wherein said second margin terminating doping region does not have overlap with trench bottom of said margin terminating trench gate.

4. The trench MOSFET as claimed in claim 1, wherein said gate metal electrically connects with said margin terminating trench gate.

5. The trench MOSFET as claimed in claim 1, wherein said source metal electrically connects with said margin terminating trench gate.