Programmable fuse/non-volatile memory structures using externally heated phase change material

• US 7,411,818 B1
• Filed: 02/07/2007
• Issued: 08/12/2008
• Est. Priority Date: 02/07/2007
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Park, Byeongju, Kim, Deok-kee, Krusin-Elbaum, Lia, Iyer, Subramanian S., Newns, Dennis M., Elmegreen, Bruce G.
• Primary Examiner(s): NGUYEN, TAN
• Application Number:
  US11/672,110
• Publication Number:
  US 20080186760A1
• Time in Patent Office: 552 Days
• Field of Search: 365/113, 257/4
• US Class Current: 365/163
• CPC Class Codes: G11C 11/5678 using amorphous/crystalline phase transition storage elements
• CPC Class Codes: G11C 13/0004 comprising amorphous/crystalline phase transition cells
• CPC Class Codes: G11C 13/0069 Writing or programming circuits or methods
• CPC Class Codes: G11C 2013/008 Write by generating heat in the surroundings of the memory material, e.g. thermowrite
• CPC Class Codes: H10B 63/30 comprising selection components having three or more electrodes, e.g. transistors
• CPC Class Codes: H10N 70/063 by etching of pre-deposited switching material layers, e.g. lithography
• CPC Class Codes: H10N 70/231 based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect
• CPC Class Codes: H10N 70/253 having three or more terminals, e.g. transistor-like devices
• CPC Class Codes: H10N 70/821 Device geometry
• CPC Class Codes: H10N 70/8613 Heating or cooling means other than resistive heating electrodes, e.g. heater in parallel
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe
• CPC Class Codes: H10N 70/884 Other compounds of groups 13-15, e.g. elemental or compound semiconductors

Abstract

A programmable phase change material (PCM) structure includes a heater element formed at a transistor gate level of a semiconductor device, the heater element further including a pair of electrodes connected by a thin wire structure with respect to the electrodes, the heater element configured to receive programming current passed therethrough, a layer of phase change material disposed on top of a portion of the thin wire structure, and sensing circuitry configured to sense the resistance of the phase change material.

Claims

1. A method of forming a programmable phase change material (PCM) structure, the method comprising:

forming a polysilicon layer over a semiconductor substrate, at a location corresponding to a transistor gate level of a semiconductor device;

patterning the polysilicon layer so as to define a pair of electrodes and a thin wire structure connecting the electrodes;

forming a silicide metal layer over the patterned polysilicon layer so as to define a heater element; and

forming a layer of phase change material disposed on top of a portion of the thin wire structure of the heater element;

wherein the portions of the silicide metal layer corresponding to the thin wire structure in contact with a portion of the phase change material are configured to selectively heat the portion of phase change material in a manner that programs the phase change material into one of a low resistance crystalline state and a high resistance amorphous state.

2. The method of claim 1, wherein the phase change material further comprises one of a Ge—

Sb—

Te (GST) alloy material and a GeSb₄ material.

3. The method of claim 1, wherein the silicide metal comprises one of:

titanium silicide, cobalt silicide, nickel silicide, platinum silicide, tungsten silicide, tantalum silicide, erbium silicide and ytterbium silicide.

4. The method of claim 1, wherein a portion of the polysilicon layer is patterned as a gate electrode for a programming transistor connected in series with the heater element.

5. The method of 4, further comprising forming one or more contact vias on an extended portion of the phase change material not in direct contact with the thin wire structure, the one or more contact vias configured to provide a connection to sense circuitry configured to sense the resistance of the phase change material.