Monolithic MOSFET and Schottky diode device

• US 20080224211A1
• Filed: 03/12/2007
• Published: 09/18/2008
• Est. Priority Date: 03/12/2007
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Kinzer, Daniel M., He, Donald
• Granted Patent: US 7,564,099 B2
• Time in Patent Office: Days
• US Class Current: 257/341
• CPC Class Codes: H01L 27/0705 comprising components of the field effect type
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/7806 the other device being a Schottky barrier diode
• 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 29/7827 Vertical transistors H01L29/7802, H01L29/78642 take precedence
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A Schottky diode is integrated into a planar or trench topology MOSFET having parallel spaced source regions diffused into spaced base stripes. The diffusions forming the source and base stripes are interrupted to permit the drift region to extend to the top of the die and receive a Schottky barrier metal and the source contact. The MOSFET and Schottky share the same drift region, and the pitch between base and source stripes is not changed to receive the Schottky structure.

Claims

1. An integrated MOSFET and Schottky diode comprising a silicon die having top and bottom surfaces, a body portion of one conductivity type extending toward said top surface, a plurality of parallel base strips of another conductivity type extending into said body portion from said top surface;

a plurality of source region strips extending into respective ones of said base strips to define invertible channel regions; and

a gate structure extending along a same direction as said parallel base strips for each of said invertible channel regions;

at least selected ones of said source and base strips having interruption areas to serve as schottky regions along their lengths and oriented transverse to the longitudinal axis thereof and the longitudinal axis of at least one gate structure;

said body portion extending to said top surface at said interruption areas;

a source contact connected to said source regions and a Schottky contact connected to said body portion at said interruption areas.

2. The device of claim 1, further comprising a conductive silicide connected directly to said interruption areas.

3. The device of claim 1, wherein said body portion is N type conductivity.

4. The device of claim 1, wherein said device is a planar device and said invertible channel regions are parallel to said top surface.

5. The device of claim 1, wherein said device is a trench type device and said invertible channel regions are perpendicular to said top surface.

6. The device of claim 5, wherein said device has plural spaced trenches defining mesas between adjacent pairs of trenches;

said source region strips being disposed along the top edges of said mesas, and conductive polysilicon gate masses filling at least selective ones of said trenches.

7. The device of claim 6, which further includes a termination trench in the outer periphery of said die and containing a conductive polysilicon mass;

and a conductive gate bus disposed on said top surface and contacting each of said polysilicon gate masses.

8. The device of claim 1, wherein said source contact and said Schottky contact are insulated segments of a common conductive layer.

9. The device of claim 6, which further includes a conductive silicide connected directly to said interruption areas.

12. The device of claim 6, wherein said source contact and said Schottky contact are insulated segments of a common conductive layer.

10-11. -11. (canceled)