Method for forming trench semiconductor device having Schottky barrier structure

• US 10,593,760 B2
• Filed: 08/02/2018
• Issued: 03/17/2020
• Est. Priority Date: 08/02/2018
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Inventors: Thomason, Michael, Quddus, Mohammed T., Mudholkar, Mihir
• Primary Examiner(s): Payen, Marvin
• Application Number:
  US16/053,400
• Publication Number:
  US 20200044027A1
• Time in Patent Office: 593 Days
• CPC Class Codes: H01L 21/0435 Schottky electrodes
• CPC Class Codes: H01L 21/28537 Deposition of Schottky electrodes
• 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 29/0891 of field-effect transistors with Schottky gate
• CPC Class Codes: H01L 29/47 Schottky barrier electrodes H01L29/435 takes precedence
• CPC Class Codes: H01L 29/66143 Schottky diodes
• CPC Class Codes: H01L 29/872 Schottky diodes
• CPC Class Codes: H01L 29/8725 of the trench MOS barrier type [TMBS]

Abstract

A method for forming a semiconductor device includes providing a region of semiconductor material. The method includes providing a trench structure having a trench extending into the region of semiconductor material from a first major surface, and a conductive material disposed within the trench and separated from the region of semiconductor material by a dielectric region. The method includes providing a Schottky contact region disposed adjacent to the first major surface and adjacent to the trench structure. In one example, providing the Schottky contact region comprises forming a first layer of material consisting essentially of titanium and having a first thickness; forming a second layer of material disposed adjacent to the first layer of material consisting essentially of nickel-platinum and having a second thickness; annealing the first layer of material and the second layer of material; and after the step of annealing, removing any unreacted portions of the first layer of material and the second layer of material. In another example, providing the Schottky contact region comprises providing a layer of material consisting essentially of nickel-chrome.

Claims

1. A method of forming a semiconductor device, comprising:

providing a region of semiconductor material comprising a first major surface and a second major surface opposite to the first major surface;

providing a trench structure comprising;

a trench extending into the region of semiconductor material from the first major surface; and

a conductive material disposed within the trench and separated from the region of semiconductor material by a dielectric region; and

providing a Schottky contact region disposed adjacent to the first major surface and adjacent to the trench structure, wherein providing the Schottky contact region comprises;

forming a first layer of material disposed adjacent to the first major surface, the first layer of material comprising titanium and having a first thickness;

forming a second layer of material disposed adjacent to the first layer of material, the second layer of material comprising nickel-platinum and having a second thickness;

exposing the first layer of material and the second layer of material to a temperature in a range from about 650 degrees Celsius through about 700 degrees Celsius; and

after the step of exposing, removing any unreacted portions of the first layer of material and the second layer of material.

2. The method of claim 1, wherein:

forming the first layer of material comprises forming the first layer of material consisting essentially of titanium.

3. The method of claim 1, wherein:

forming the first layer of material comprises forming the first layer of material consisting of titanium.

4. The method of claim 1, wherein:

forming the first layer of material comprises providing the first thickness in a range from about 300 Angstroms through about 800 Angstroms.

5. The method of claim 1, wherein:

forming the second layer of material comprises forming the second layer of material consisting essentially of nickel-platinum.

6. The method of claim 1, wherein:

forming the second layer of material comprises forming the second layer of material consisting of nickel-platinum.

7. The method of claim 1, wherein:

forming the second layer of material comprises providing the second thickness in a range from about 100 Angstroms through about 350 Angstroms.

8. The method of claim 1, further comprising:

forming a conductive layer overlying the Schottky contact region.

9. The method of claim 1, wherein:

providing the trench structure comprises providing an active trench structure.

10. The method of claim 1, wherein:

exposing the first layer of material and the second layer of material to the temperature comprises exposing for a time period of about 30 seconds to about 45 seconds.

11. The method of claim 1, wherein:

providing the Schottky contact region comprises providing a first thickness to second thickness ratio greater than or equal to 2;

1.

12. A method of forming a semiconductor device, comprising:

providing a region of semiconductor material comprising a first major surface and a second major surface opposite to the first major surface;

providing a trench structure comprising;

a trench extending into the region of semiconductor material from the first major surface; and

a conductive material disposed within the trench and separated from the region of semiconductor material by a dielectric region, wherein;

the dielectric region is disposed along opposing sidewall surfaces of the trench and disposed along a lower surface of the trench; and

the dielectric region comprises a first uppermost surface; and

providing a Schottky contact region disposed adjacent to the first major surface and adjacent to the trench structure, wherein providing the Schottky contact region comprises;

forming a first layer of material disposed adjacent to the first major surface, the first layer of material consisting essentially of titanium and having a first thickness;

forming a second layer of material disposed adjacent to the first layer of material, the second layer of material consisting essentially of nickel-platinum and having a second thickness;

exposing the first layer of material and the second layer of material to a temperature in a range from about 650 degrees Celsius through about 700 degrees Celsius; and

after the step of exposing, removing any unreacted portions of the first layer of material and the second layer of material.

13. The method of claim 12, wherein:

providing the Schottky contact region comprises providing a first thickness to second thickness ratio greater than or equal to 1.33;

1.

14. The method of claim 12, wherein:

providing the Schottky contact region comprises providing a first thickness to second thickness ratio of about 6;

1.

15. The method of claim 12, wherein:

providing the trench structure comprises providing the first uppermost surface of the dielectric region extending above an upper surface of the Schottky region in a cross-sectional view.

16. The method of claim 12, further comprising:

forming a conductive layer overlying the Schottky contact region, wherein;

providing the trench structure comprises providing an active trench structure; and

exposing the first layer of material and the second layer of material to the temperature comprises exposing for a time period of about 30 seconds to about 45 seconds in nitrogen.

17. The method of claim 12, wherein:

providing the region of semiconductor material comprises;

providing a semiconductor substrate; and

providing a semiconductor layer overlying the substrate;

the semiconductor layer includes the first major surface; and

the semiconductor layer comprises a non-uniform dopant profile over its thickness.

18. A method of forming a semiconductor device, comprising:

providing a region of semiconductor material comprising a first major surface and a second major surface opposite to the first major surface;

providing a trench structure comprising;

a trench extending into the region of semiconductor material from the first major surface; and

a conductive material disposed within the trench and separated from the region of semiconductor material by a dielectric region, wherein;

the dielectric region is disposed along opposing sidewall surfaces of the trench and disposed along a lower surface of the trench; and

the dielectric region comprises a first uppermost surface; and

providing a Schottky contact region disposed adjacent to the first major surface and adjacent to the trench structure, wherein providing the Schottky contact region comprises;

forming a conductive structure comprising;

a first layer of material consisting essentially of titanium disposed adjacent to the first major surface and a second layer of material disposed adjacent to the first layer of material and consisting essentially of nickel-platinum;

exposing the conductive structure to an elevated temperature to form a silicide structure;

after the step of exposing, removing any unreacted portions of the conductive structure,

and wherein;

forming the conductive structure comprises;

forming the first layer of material consisting essentially of titanium having a first thickness;

forming the second layer of material consisting essentially of nickel-platinum having a second thickness; and

providing a first thickness to second thickness ratio greater than or equal to 1.33;

1; and

exposing comprises exposing the first layer of material and the second layer of material to a temperature in a range from about 650 degrees Celsius through about 700 degrees Celsius.