Post-fabrication self-aligned initialization of integrated devices

• US 9,196,829 B2
• Filed: 03/15/2013
• Issued: 11/24/2015
• Est. Priority Date: 08/31/2010
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: GlobalFoundries, Inc.
• Inventors: Franceschini, Michele M., Karidis, John P.
• Primary Examiner(s): MENZ, LAURA MARY
• Application Number:
  US13/833,139
• Publication Number:
  US 20130200321A1
• Time in Patent Office: 984 Days
• US Class Current: 1/1
• CPC Class Codes: H10N 70/021 Formation of the switching material, e.g. layer deposition
• CPC Class Codes: H10N 70/063 by etching of pre-deposited switching material layers, e.g. lithography
• CPC Class Codes: H10N 70/20 Multistable switching devices, e.g. memristors
• 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 70/823 adapted for essentially horizontal current flow, e.g. bridge type devices
• CPC Class Codes: H10N 70/826 adapted for essentially vertical current flow, e.g. sandwich or pillar type devices
• CPC Class Codes: H10N 70/828 Current flow limiting means within the switching material region, e.g. constrictions
• CPC Class Codes: H10N 70/8413 adapted for resistive heating
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe

Abstract

Defining an active region of a phase change memory (PCM) cell including depositing a first layer of material having a first chemical composition. A second layer of material having a second chemical composition is deposited on top of the first layer of material. An electrical current pulse is applied to locally heat a region of the first layer of material and the second layer of material to cause at least one of an inter-diffusion and a liquid mixing of the first layer of material and the second layer of material. This results in in the PCM cell containing a self-aligned region that includes a phase change material that is a mixture of the first chemical composition and the second chemical composition.

Claims

1. A method of defining an active region of a phase change memory (PCM) cell comprising:

depositing a first layer of material having a first chemical composition, the depositing on top of a first conductive electrode region that forms a bit line and on top of a second conductive electrode region that includes a u-trench;

depositing a second layer of material having a second chemical composition on top of the first layer of material;

depositing a resist layer on top of the second layer of material; and

applying an electrical current pulse to locally heat a region of the first layer of material and the second layer of material to cause at least one of an inter-diffusion and a liquid mixing of the first layer of material and the second layer of material, resulting in the PCM cell comprising a self-aligned region comprising a phase change material that is a mixture of the first chemical composition and the second chemical composition and a portion of the resist layer being sensitized;

wherein the portion of the resist layer that is sensitized covers the self-aligned region of the PCM cell.

2. The method of claim 1, wherein the applying the electrical current pulse causes an electrical current to flow from the first conductive electrode region to the second conductive electrode region, the electrical current passing through at least the first layer of material.

3. The method of claim 1, wherein the first layer of material is an amorphous threshold switching material having high electrical resistivity at low electric field strength and substantially reduced electrical resistivity at electric field strengths above a threshold.

4. The method of claim 1, wherein the first layer of material is an insulator and the second layer of material is the phase change material, or the first layer of material is the phase change material and the second layer of material is an insulator.

5. The method of claim 1, wherein the PCM cell is characterized by a parallel path memory cell structure.

6. The method of claim 1, wherein the PCM cell is characterized by a vertical path memory cell structure.