Shielded gate trench (SGT) MOSFET devices and manufacturing processes

• US 7,936,011 B2
• Filed: 12/11/2009
• Issued: 05/03/2011
• Est. Priority Date: 02/17/2006
• Status: Active Grant

• Current Assignee: Alpha & Omega Semiconductor, Ltd.
• Original Assignee: Alpha & Omega Semiconductor, Ltd.
• Inventors: Lui, Sik K, Bhalla, Anup
• Primary Examiner(s): Tran; Tan N
• Application Number:
  US12/653,355
• Publication Number:
  US 20100090276A1
• Time in Patent Office: 508 Days
• Field of Search: 257/330, 257/331, 257/332, 257/333, 257/334, 257/E29.201, 257/E29.26
• 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 29/66734 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

Abstract

This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one of the cells constituting an active cell has a source region disposed next to a trenched gate electrically connecting to a gate pad and surrounding the cell. The trenched gate further has a bottom-shielding electrode filled with a gate material disposed below and insulated from the trenched gate. At least one of the cells constituting a source-contacting cell surrounded by the trench with a portion functioning as a source connecting trench is filled with the gate material for electrically connecting between the bottom-shielding electrode and a source metal disposed directly on top of the source connecting trench. The semiconductor power device further includes an insulation protective layer disposed on top of the semiconductor power device having a plurality of source openings on top of the source region and the source connecting trench provided for electrically connecting to the source metal and at least a gate opening provided for electrically connecting the gate pad to the trenched gate.

Claims

1. A semiconductor power device comprising a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate wherein:

at least one of said cells constituting an active cell having a source region disposed next to a trenched gate electrically connecting to a gate pad and surrounding said cell wherein said trenched gate further having a bottom shielding electrode filled with a gate material disposed below and insulated from said trenched gate; and

at least one of said cells constituting a source contacting cell surrounded by said trench with a portion functioning as a source connecting trench filled with said gate material for electrically connecting between said bottom shielding electrode and a source metal disposed directly on top of said source connecting trench wherein said source connecting trench is formed at a location where two trenches intersect;

an insulation protective layer disposed on top of said semiconductor power device having a gate opening provided for electrically connecting said gate pad to said trenched gate;

said gate opening is disposed directly above a gate runner trench in a termination area of said semiconductor power device;

said gate runner trench is wider and deeper than said trench provided for forming said trenched gate therein;

wherein said runner trench further includes a shield gate trench structure with said bottom shielding electrode;

wherein said bottom shielding electrode filled with said gate material having stepwise tapered profiled toward a bottom of said trench with a lining layer surrounded said gate material having a correspondingly stepwise increased thickness.

2. The trenched power semiconductor power device of claim 1 further comprising:

said insulation protective layer disposed on top of said semiconductor power device having a plurality of source openings on top of said source region and said source connecting trench provided for electrically connecting to said source metal.

3. The semiconductor power device of claim 1 further comprising:

a deep body-dopant region in a termination area to function as a guard ring or Junction-termination extension type termination.

4. The semiconductor power device of claim 3 wherein:

said deep body-dopant region is deeper than and encompassing said gate runner trench in said termination area.

5. The semiconductor power device of claim 1 wherein:

said power transistor cells further comprising trenched metal oxide semiconductor field effect transistor (MOSFET) cells.