Non-activated guard ring for semiconductor devices

• US 7,229,866 B2
• Filed: 09/07/2004
• Issued: 06/12/2007
• Est. Priority Date: 03/15/2004
• Status: Expired due to Fees

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Velox Semiconductor Corporation (Power Integrations Incorporated)
• Inventors: Shelton, Bryan S., Murphy, Michael, Liu, Linlin, Zhu, Ting Gang, Pophristic, Milan, Ceruzzi, Alex D.
• Primary Examiner(s): Lee; Calvin
• Application Number:
  US10/935,000
• Publication Number:
  US 20050202661A1
• Time in Patent Office: 1,008 Days
• Field of Search: 257/280, 257/484, 438/167, 438/570
• US Class Current: 438/167
• 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 29/0619 with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
• 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 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/207 further characterised by the doping material H01L29/2006 takes precedence
• CPC Class Codes: H01L 29/32 the imperfections being within the semiconductor body
• CPC Class Codes: H01L 29/452 on AIII-BV compounds
• CPC Class Codes: H01L 29/475 on AIII-BV compounds
• CPC Class Codes: H01L 29/66143 Schottky diodes
• CPC Class Codes: H01L 29/66212 Schottky diodes
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A guard ring is formed in a semiconductor region that is part of a Schottky junction or Schottky diode. The guard ring is formed by ion implantation into the semiconductor contact layer without completely annealing the semiconductor contact layer to form a high resistance region. The guard ring may be located at the edge of the layer or, alternatively, at a distance away from the edge of the layer. A Schottky metal contact is formed atop the layer, and the edges of the Schottky contact are disposed atop the guard ring.

Claims

1. A method of forming a guard ring in a semiconductor structure, said method comprising:

providing a semiconductor body including a contact layer;

implanting at least one ion species into at least one portion of said contact layer to form at least one implanted region therein, said at least one implanted region being disposed at least adjacent to a portion of a surface of said contact layer upon which an edge of a Schottky metallic contact is disposed or is to be disposed; and

subsequently processing said semiconductor body without annealing said implanted region.

2. A Schottky diode formed by a method including forming a guard ring as claimed in claim 1, wherein said step of providing a semiconductor body includes the step of forming at least one semiconductor layer on a surface of a substrate, said semiconductor layer at least including said contact layer, whereby said semiconductor body includes said substrate and said at least one semiconductor layer;

said method further comprising

forming the Schottky metallic contact atop at least part of said contact layer to form a Schottky junction therewith.

3. A Schottky diode formed by a method as claimed in claim 2 further comprising forming at least one further metallic contact on said contact layer in substantially ohmic contact therewith.

4. A Schottky diode formed by a method as claimed in claim 2 further comprising patterning and etching at least one region of said semiconductor layer prior to forming said metallic contact to define at least one further surface in said semiconductor body and at lease one mesa, said mesa projecting upwardly from said further surface and at least including said contact layer, said Schottky junction being disposed atop said mesa.

5. A Schottky diode formed by a method as claimed in claim 4 wherein said patterning and etching step is carried out prior to implanting said ion species.

6. A Schottky diode formed by a method as claimed in claim 4 wherein said further surface of said semiconductor body is a lower contact surface, and said method includes forming at least one further metallic contact on said lower contact surface in substantially ohmic contact therewith.

7. A Schottky diode formed by a method as claimed in claim 4 wherein said patterning and etching step included patterning and etching one or more regions of said semiconductor body to define a plurality of mesas projecting upwardly from said further surface, at least some of said plurality of mesas each including at least one or said one or more guard rings.

8. A Schottky diode formed by a method as claimed in claim 2 wherein said substrate is an electrically insulating material.

9. A Schottky diode formed by a method as claimed in claim 2 wherein said substrate is a semiconductor, said method further including forming at least one further metallic contact on another surface of said substrate in substantially ohmic contact therewith.

10. A Schottky diode formed by a method including forming a guard ring as claimed in claim 1, wherein said step of providing a semiconductor body includes the step of forming at least one semiconductor layer on a surface of a substrate, said semiconductor layer at least including said contact layer, whereby said semiconductor body includes said substrate and said at least one semiconductor layer;

said method further comprising forming a metallic contact atop at least part of said contact layer to form a Schottky junction therewith prior to implanting said at least one ion species, said metallic contact masking said implanting of said at least one ion species such that said implanted region is self aligned to said metallic contact.

11. A Schottky diode formed by a method as claimed in claim 10 further comprising forming at least one further metallic contact on said semiconductor layer in substantially ohmic contact therewith prior to implanting said at least one ion species, said ohmic contact further masking said implanting of said at least one ion species.

12. A Schottky diode formed by a method as claimed in claim 10 further comprising patterning and etching at least one region of said semiconductor layer prior to forming said metallic contact to define at least one lower contact surface in said semiconductor body and at least one mesa, said mesa projecting upwardly from said further surface and at least including said doped region, said Schottky metallic contact being formed atop said mesa, and forming at least one further metallic contact on said lower contact surface in substantially ohmic contact therewith prior to implanting said at least one ion species, said ohmic contact further masking said implanting of said at least one ion species.