PROGRAMMABLE ELECTRONIC FUSE

• US 20090179302A1
• Filed: 01/16/2009
• Published: 07/16/2009
• Est. Priority Date: 10/21/2004
• Status: Abandoned Application

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kothandaraman, Chandrasekharan, Iyer, Subramanian
• Application Number:
  US12/355,056
• Publication Number:
  US 20090179302A1
• Time in Patent Office: Days
• US Class Current: 257/529
• CPC Class Codes: H01L 23/5256 comprising fuses, i.e. connections having their state changed from conductive to non-conductive
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A programmable device (eFuse), includes: a substrate (10); an insulator (13) on the substrate; an elongated semiconductor material (12) on the insulator, the elongated semiconductor material having a first end (12a), a second end (12b), a fuse link (11) between the ends, and an upper surface S. The semiconductor material includes a dopant having a concentration of at least 10*17/cc. The first end (12a) is wider than the second end (12b), and a metallic material is disposed on the upper surface. The metallic material is physically migratable along the upper surface responsive to an electrical current I flowable through the semiconductor material and through the metallic material.

Claims

1. A programmable device, comprising:

a substrate;

an insulator on said substrate;

an elongated semiconductor material on said insulator, said elongated semiconductor material having a first end, a second end, a fuse link between the ends, and an upper surface.

wherein said semiconductor material includes a dopant having a concentration of at least 10*17/cc,

said first end is wider than said second end, and

a metallic material is disposed on said upper surface, said metallic material being physically migratable along said upper surface responsive to an electrical current I flowable through said semiconductor material and through said metallic material.

2. The programmable device of claim 1, wherein the dopant is “

n”

or “

p”

type and the semiconductor material is doped in the range of approximately 10*17/cc to approximately 10*21/cc.

3. A programmable device of claim 1, further comprising an insulating layer overlying the silicide layer, the insulating layer being non-reactive with the metallic layer during a programming of the device.

4. The programmable device as claimed in claim 1, further comprising an energy source connected to said elongated semiconductor material, for causing an electrical current to flow through said elongated semiconductor material and through said metallic material for a predetermined time, and for causing said metallic material to migrate along said upper surface.

5. The programmable device as claimed in claim 1, wherein said elongated semiconductor material is selected to have a thickness of about 120 nm

6. The programmable device as claimed in claim 1, where said semiconductor material is selected to have a substantially uniform thickness in the range of approximately 60 nm to approximately 250 nm

7. The programmable device as claimed in claim 1, wherein said fuse link has a length greater than five times the fuse link width.

8. The programmable device of claim 1, wherein said fuse link has a length that is less than 15 times the fuse link width.

9. The programmable device as claimed in claim 1, wherein said metallic material is a metallic silicide selected from the group consisting of Nickel silicide and Cobalt silicide.

10. The programmable device of claim 1, wherein the elongated semiconductor material is a polysilicon and the metallic material is a metallic alloy, and the ratio of resistivities of the polysilicon and metallic alloy ranges between 20 to 50, and preferably 30.

11. The programmable device of claim 1, wherein a thickness ratio of the semiconductor material and metallic material ranges between 3 to 8, and preferably about 6.

12. The programmable device of claim 1, wherein a non-reactive insulating layer of SiN is disposed above the metallic material.

13. The programmable device of claim 12, wherein the SiN has a thickness greater than 3000 angstroms.

14. The programmable device of claim 1, wherein the insulator has a substantially uniform thickness of approximately 3000 angstroms.

15. A programmable device for reliably achieving a post-programming resistance greater than 5 Kohms, said programmable device comprising:

a substrate;

an insulator on said substrate;

an elongated semiconductor material having a constant first thickness and disposed on said insulator, said elongated semiconductor material having a first end, a second end, a fuse link between the ends, and an upper surface;

a metallic material having a constant second thickness and disposed on said upper surface; and

at least one programming transistor configured to supply an electrical current, I, having a magnitude between a first value and a second value through said elongated semiconductor material and through said metallic material;

wherein said semiconductor material includes a dopant of one conductivity type at a concentration of at least 10¹⁷ dopants/cc, while not including any dopant of an opposite conductivity type;

said first end is wider than said second end, and said metallic material being physically migratable along said upper surface responsive to said electrical current;

wherein said first value is set between a first range of current level that causes a post-program resistance distribution that is wide and on a low side of approximately 5 Kohms and a second range of current level that causes said post-program resistance to be greater than 5 Kohms and tightly distributed without any rupture in said elongated semiconductor material; and

wherein said second value is set between said second range of current level and a third range of current level that ruptures said elongated semiconductor material and said post-program resistance shows a two mode distribution.