# US 7,411,818 B1 · Programmable fuse/non-volatile memory structures using externally heated phase change material

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- Number: US 7,411,818 B1
- Document ID: US7411818B1
- Status: Granted
- Kind: B1
- Application number: 11/672,110
- Filed: 2007-02-07
- Published: 2008-08-07
- Granted: 2008-08-12
- Earliest claimed: 2007-02-07
- Assignees: International Business Machines Corporation
- Inventors: Bruce G. Elmegreen; Subramanian S. Iyer; Deok-kee Kim; Lia Krusin-Elbaum; Dennis M. Newns; Byeongju Park
- Web page: https://patentgrep.com/patent/US7411818B1

## CPC

- H10B 63/30: {comprising selection components having three or more electrodes, e.g. transistors}
- G11C 11/5678: {using amorphous/crystalline phase transition storage elements}
- G11C 13/0004: {comprising amorphous/crystalline phase transition cells}
- G11C 13/0069: {Writing or programming circuits or methods}
- H10N 70/063: {by etching of pre-deposited switching material layers, e.g. lithography}
- H10N 70/231: {based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect}
- H10N 70/253: {having three or more electrodes, e.g. transistor-like devices}
- H10N 70/821: {Device geometry}
- H10N 70/8613: {Heating or cooling means other than resistive heating electrodes, e.g. heater in parallel}
- H10N 70/8828: {Tellurides, e.g. GeSbTe}
- H10N 70/884: {based on at least one element of group IIIA, IVA or VA, e.g. elemental or compound semiconductors (compounds of sulfur, selenium or tellurium, e.g. chalcogenides H10N70/882; oxides or nitrides H10N70/883)}
- G11C 2013/008: {Write by generating heat in the surroundings of the memory material, e.g. thermowrite}
- H10B: ELECTRONIC MEMORY DEVICES
- G11C: STATIC STORES (semiconductor memory devices H10B)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## 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

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

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.

### Claim 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.