# US 7,459,266 B2 · Phase-change memory cell and method of fabricating the phase-change memory cell

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- Number: US 7,459,266 B2
- Document ID: US7459266B2
- Status: Granted
- Kind: B2
- Application number: 11/150,184
- Filed: 2005-06-13
- Published: 2005-10-13
- Granted: 2008-12-02
- Earliest claimed: 2004-01-30
- Assignees: International Business Machines Corporation
- Inventors: Jonathan Zanhong Sun; Simone Raoux; Hemantha Wichramasinghe
- Web page: https://patentgrep.com/patent/US7459266B2

## CPC

- G11C 13/0069: {Writing or programming circuits or methods}
- G11C 13/0004: {comprising amorphous/crystalline phase transition cells}
- H10N 70/026: {by physical vapor deposition, e.g. sputtering}
- H10N 70/061: {Shaping switching materials}
- H10N 70/231: {based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect}
- H10N 70/826: {adapted for essentially vertical current flow, e.g. sandwich or pillar type devices}
- H10N 70/8613: {Heating or cooling means other than resistive heating electrodes, e.g. heater in parallel}
- H10N 70/8828: {Tellurides, e.g. GeSbTe}
- G11C 2213/52: Structure characterized by the electrode material, shape, etc.
- G11C: STATIC STORES (semiconductor memory devices H10B)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A memory cell and method of fabricating the memory cell includes an insulating layer formed on a first electrode layer, the insulating layer having a first opening, a stencil layer formed on the insulating layer, and having a second opening formed in an area of the first opening, a phase-change material layer formed on a surface of the first electrode layer in the first opening, and an electrically conductive layer including a first portion formed on the stencil layer and defining a second electrode layer and a second portion formed on the phase-change material layer.

## Claims

### Claim 1

A method of fabricating a memory cell, comprising:
forming a first electrode layer including a first electrically conductive material, forming an insulating layer, and forming a stencil layer having an opening, in that order, on a substrate;
etching said insulating layer through said opening in said stencil layer, to expose a surface of said first electrode layer;
depositing a second electrically conductive material through said opening in said stencil layer onto said surface of said first electrode layer;
depositing a phase-change material layer through said opening in said stencil layer onto said second electrically conductive material; and
depositing a third electrically conductive material to form a second electrode layer and a pillar structure through said opening on said phase-change material layer, using a spread-angle for deposition which is greater than a spread-angle for deposition for said phase-change material, such that said phase-change material layer is surrounded by said second and third electrically conductive materials,
wherein said etching said insulating layer comprises undercut etching in which a portion of said insulating layer underneath said stencil layer is etched, such that an opening is formed in said insulating layer which has a larger diameter than said opening in said stencil layer,
wherein said third electrically conductive material is deposited using a deposition beam having a spread-angle for deposition which is greater than the spread-angle for deposition for said phase-change material layer by using one of different deposition conditions, and different deposition techniques to form said phase-change material layer and said pillar structure, and
wherein said depositing said phase-change material layer comprises directionally depositing said phase-change material layer, such that said phase-change material layer is deposited off center from said opening in said stencil layer.