Integrated series schottky and FET to allow negative drain voltage

• US 20030102886A1
• Filed: 01/06/2003
• Published: 06/05/2003
• Est. Priority Date: 11/07/2001
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Ranjan, Niraj
• Granted Patent: US 6,707,101 B2
• Time in Patent Office: Days
• US Class Current: 326/19
• CPC Class Codes: H01L 29/0615 by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE] LDD or drain offset regions H01L29/7833
• CPC Class Codes: H01L 29/7393 Insulated gate bipolar mode transistors, i.e. IGBT; IGT; COMFET
• CPC Class Codes: H01L 29/7816 Lateral DMOS transistors, i.e. LDMOS transistors
• CPC Class Codes: H01L 29/782 the other device being a Schottky barrier diode
• CPC Class Codes: H01L 29/7839 with Schottky drain or source contact
• CPC Class Codes: H03K 17/04163 in field-effect transistor switches
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/6871 the output circuit comprising more than one controlled field-effect transistor

Abstract

A high side driver chip for MOSgated devices which controls a non resistive, or non inductive load has a vertical conduction refresh MOSFET integrated into the chip for connecting a V_s node to ground to discharge the load capacitance. A Schottky diode is also integrated with the refresh MOSFET to prevent forward conduction of a parasitic diode of the vertical conduction MOSFET.

Claims

1. A high voltage MOSFET with a large voltage drop body drain diode;

said high voltage MOSFET comprising a silicon body having laterally spaced source and drain diffusions, an invertable lateral channel region operable to permit conduction between said source and drain region when its surface concentration is inverted; and

a MOSgate structure coupled to said lateral channel and operable to invert said channel in response to a gate signal to said MOSgate structure;

metallic source and drain contacts connected to said source and drain regions respectively;

at least one of said source or drain regions having a concentration sufficiently low to define a Schottky diode when contacted by its respective contact.

3. The device of claim 1, wherein said refresh MOSFET is a high voltage MOSFET with a large voltage drop body drain diode;

said refresh MOSFET comprising a silicon body having laterally spaced source and drain diffusion an invertable lateral channel region operable to permit conduction between said source and drain region when its surface concentration is inverted; and

a MOSgate structure coupled to said lateral channel and operable to invert said channel in response to a gate signal to said MOSgate structure;

metallic source and drain contacts connected to said source and drain regions respectively;

at least one of said source or drain regions having a concentration sufficiently low to define a Schottky diode when contacted by its respective contact.

2. The device of claim 5, wherein said high voltage MOSFET has an inherent parasitic diode;

said Schottky diode being poled oppositely to said parasitic diode.

4. The device of claim 7, wherein said refresh MOSFET has an inherent parasitic diode;

said Schottky diode being poled oppositely to said parasitic diode.