Planar TMBS rectifier

• US 8,044,461 B2
• Filed: 06/07/2010
• Issued: 10/25/2011
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Inventors: Session, Fred
• Primary Examiner(s): Potter, Roy K
• Application Number:
  US12/795,368
• Publication Number:
  US 20110079845A1
• Time in Patent Office: 505 Days
• Field of Search: 257/334, 257/E27.068, 257/267, 257/280, 257/284, 257/471, 257/E33.051, 438/167, 438/57
• US Class Current: 257/334
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/47 Schottky barrier electrodes H01L29/435 takes precedence
• CPC Class Codes: H01L 29/66727 with a step of recessing the source electrode
• 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 29/7806 the other device being a Schottky barrier diode
• 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 29/872 Schottky diodes
• CPC Class Codes: H01L 29/8725 of the trench MOS barrier type [TMBS]

Abstract

A monolithically integrated trench FET and Schottky diode includes a plurality of trenches extending into a FET region and a Schottky region of a semiconductor layer. A trench in the Schottky region includes a dielectric layer lining the trench sidewalls, and a conductive electrode having a top surface that is substantially coplanar with a top surface of the semiconductor layer adjacent the trench. An interconnect layer electrically contacts the semiconductor layer in the Schottky region so as to form a Schottky contact with the semiconductor layer.

Claims

1. A trench MOS barrier schottky (TMBS) rectifier comprising:

a plurality of trenches extending into a semiconductor layer,

a dielectric layer lining the trench sidewalls;

a conductive electrode having a top surface that is substantially coplanar with a top surface of the semiconductor layer adjacent the trench; and

an interconnect layer comprising a conformal barrier metal layer which contacts the semiconductor layer so as to form a schottky contact with the semiconductor layer.

2. The TMBS rectifier of claim 1 wherein the conformal barrier metal layer directly contacts the conductive electrode in each trench.

3. The TMBS rectifier of claim 1 wherein the conformal barrier metal layer is substantially planar.

4. The TMBS rectifier of claim 1 wherein a top surface of the conductive electrode in each trench is substantially coplanar with a top surface of the semiconductor layer.

5. The TMBS rectifier of claim 1 wherein the interconnect layer comprises a metal layer over and directly in contact with the conformal barrier layer.

7. The TMBS rectifier of claim 1 wherein the interconnect layer comprises a metal layer over and directly in contact with the conformal barrier layer.

6. A trench MOS barrier schottky (TMBS) rectifier comprising:

a plurality of trenches extending into a semiconductor layer,

a dielectric layer lining the trench sidewalls;

a conductive electrode having a top surface that is substantially coplanar with a top surface of the semiconductor layer adjacent the trench; and

an interconnect layer comprising a conformal barrier metal layer contacting the semiconductor layer so as to form a schottky contact with the semiconductor layer, the conformal barrier layer extending over and directly contacting the conductive electrode in each trench, a top surface of the conductive electrode in each trench being substantially coplanar with a top surface of the semiconductor layer such that the conformal barrier metal layer is substantially planar.