Discrete integrated circuit rectifier device

• US 6,498,367 B1
• Filed: 03/08/2000
• Issued: 12/24/2002
• Est. Priority Date: 04/01/1999
• Status: Expired due to Term

• Current Assignee: Diodes Incorporated
• Original Assignee: APD Semiconductor, Inc. (Diodes Incorporated)
• Inventors: Chern, Geeng-Chuan (aka Michael), Rodov, Vladimir, Chang, Paul, Hsueh, Wayne Y. W.
• Primary Examiner(s): LOKE, STEVEN HO YIN
• Application Number:
  US09/520,546
• Time in Patent Office: 1,021 Days
• Field of Search: 257/341, 257/342, 257/339, 257/330, 257/331, 257/355
• US Class Current: 257/341
• CPC Class Codes: H01L 21/2815 part or whole of the electrode is a sidewall spacer or made by a similar technique, e.g. transformation under mask, plating
• CPC Class Codes: H01L 27/0814 Diodes only
• CPC Class Codes: H01L 27/095 the components being Schottky barrier gate field-effect transistors
• 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 29/1095 Body region, i.e. base region, of DMOS transistors or IGBTs cell layout H01L29/0696
• CPC Class Codes: H01L 29/66712 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7802 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7806 the other device being a Schottky barrier diode
• CPC Class Codes: H01L 29/781 Inverted VDMOS transistors, i.e. Source-Down VDMOS transistors
• 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 29/861 Diodes
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A power rectifier having low on resistance, fast recovery time and low forward voltage drop. In a preferred embodiment, the present invention provides a power rectifier device employing a vertical device structure, i.e., with current flow between the major surfaces of the discrete device. The device employs a large number of parallel connected cells, each comprising a MOSFET structure with a gate to drain short via a common conductive layer. This provides a low V_f path through the channel regions of the MOSFET cells to the contact metallization on the other side of the integrated circuit. A thin gate structure is formed annularly around pedestal regions on the upper surface of the device and a precisely controlled body implant defines the channel region and allows controllable device characteristics, including gate threshold voltage and V_f.

Claims

1. A discrete integrated circuit rectifier device, comprising:

a semiconductor substrate having first and second surfaces and a plurality of pedestals formed on the first surface;

a MOSFET comprising a plurality of parallel connected MOSFET cells formed on the semiconductor substrate, said MOSFET cells controlling current flow between the two surfaces of said substrate;

each MOSFET cell comprising a spacer formed adjacent the side of a pedestal and defining the location of the MOSFET cell relative to the pedestal, a gate, a gate oxide, a contact region of a first conductivity type, a body region of a second conductivity type implant underlying said gate oxide and contact region, and a channel region comprising a portion of said body region underlying substantially all of said gate oxide; and

a common electrically conductive layer shorting the gate and contact regions of the plurality cells.

2. A discrete rectifier device as set out in claim 1, wherein said first conductivity type is N type and said second conductivity type is P type.

3. A discrete rectifier device as set out in claim 1, wherein said spacer is composed of polysilicon.

4. A discrete rectifier device as set out in claim 3, wherein said gate is composed of polysilicon.

5. A rectifier device as set out in claim 1, wherein the current flow through the channel regions operates in an enhancement mode of operation.

6. A rectifier device as set out in claim 1, wherein the current flow through the channel regions operates in a depletion mode of operation.

7. A rectifier device as set out in claim 1, wherein the current flow through the channel regions operates in a zero threshold mode of operation.