Semiconductor storage device and manufacturing method thereof

• US 20060266992A1
• Filed: 05/18/2006
• Published: 11/30/2006
• Est. Priority Date: 05/19/2005
• Status: Abandoned Application

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: Kurotsuchi, Kenzo, Takaura, Norikatsu, Matsui, Yuichi, Iwasaki, Tomio
• Application Number:
  US11/435,934
• Publication Number:
  US 20060266992A1
• Time in Patent Office: Days
• US Class Current: 257/4
• 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 70/826 adapted for essentially vertical current flow, e.g. sandwich or pillar type devices
• CPC Class Codes: H10N 70/8616 Thermal insulation means
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe

Abstract

Since a chalcogenide material has low adhesion to a silicon oxide film, there is a problem in that it tends to separate from the film during the manufacturing step of a phase change memory. In addition, since the chalcogenide material has to be heated to its melting point or higher during resetting (amorphization) of the phase change memory, there is a problem of requiring extremely large rewriting current. An interfacial layer comprising an extremely thin insulator or semiconductor having the function as both an adhesive layer and a high resistance layer (thermal resistance layer) is inserted between chalcogenide material layer/interlayer insulative film and between chalcogenide material layer/plug.

Claims

1. A semiconductor storage device including:

a semiconductor substrate;

a selection transistor formed on a main surface of the semiconductor substrate;

an inter-layer insulative film disposed over the selection transistor;

a plug selectively disposed to pass through the inter-layer insulative film and connected electrically to the selection transistor;

a chalcogenide material layer connected to one end of the plug and disposed so as to extend over the inter-layer insulative film;

an upper electrode disposed over the chalcogenide material layer; and

an interfacial layer formed between the chalcogenide material layer and the inter-layer insulative film so as to cover at least one end of the plug and comprising a continuous insulator not having a region where the chalcogenide material layer and the inter-layer insulative film are not in direct contact with each other

2. A semiconductor storage device according to claim 1, wherein the interfacial layer comprises a material having higher adhesiveness than the inter-layer insulative film relative to the chalcogenide material layer.

3. A semiconductor storage device according to claim 1, wherein the interfacial layer comprises a material of lower heat conductivity than that of the plug.

4. A semiconductor storage device according to claim 1, wherein the interfacial layer has a film thickness of 0.5 nm or more and 5 nm or less and is formed in contact with the lower surface of the chalcogenide material layer.

5. A semiconductor storage device according to claim 1, wherein the interfacial layer comprises at least one element selected from the group of a Ti oxide film, Zr oxide film, Hf oxide film, Ta oxide film, Nb oxide film, Cr oxide film, Mo oxide film, W oxide film, and Al oxide film.

11. A semiconductor storage device according to claim 1, wherein the interfacial layer comprising a material containing Si.

6. A semiconductor storage device including;

a semiconductor substrate;

a selection transistor formed on a main surface of the semiconductor substrate;

an inter-layer insulative film disposed over the selection transistor;

a plug selectively disposed to pass through the inter-layer insulative film and connected electrically with the selection transistor;

a chalcogenide material layer connected to one end of the plug and disposed so as to extend over the inter-layer insulative film;

an upper electrode disposed over the chalcogenide material layer; and

an interfacial layer formed between the chalcogenide material layer and the inter-layer insulative film so as to cover at least one end of the plug and comprising a continuous semiconductor not having a region where the chalcogenide material layer and the inter-layer insulative film are not in direct contact with each other

7. A semiconductor storage device according to claim 6, wherein the interfacial layer comprises a material having higher adhesiveness than the inter-layer insulative film relative to the chalcogenide material layer.

8. A semiconductor storage device according to claim 6, wherein the interfacial layer comprises a material of lower heat conductivity than that of the plug.

9. A semiconductor storage device according to claim 6, wherein the interfacial layer comprises a material of higher resistivity than that of the plug.

10. A semiconductor storage device according to claim 6, wherein the interfacial layer has a film thickness of 0.5 nm or more and 5 nm or less and is formed in contact with the lower surface of the chalcogenide material layer.

12. A semiconductor storage device comprising;

a semiconductor substrate;

a selection transistor formed on a main surface of the semiconductor substrate;

an inter-layer insulative film disposed over the selection transistor;

a plug selectively disposed to pass through the inter-layer insulative film and connected electrically with the selection transistor;

a chalcogenide material layer connected to one end of the plug and disposed so as to extend over the inter-layer insulative film;

an upper electrode disposed over the chalcogenide material layer;

an adhesion layer comprising a semiconductor formed between the chalcogenide material layer and the inter-layer insulative film; and

an interfacial layer formed between the chalcogenide material layer and the plug and comprising an alloy of a material of the adhesion layer and a material of the plug.

13. A semiconductor storage device according to claim 12, wherein the adhesion layer and the interfacial layer comprise a material having higher adhesiveness than the inter-layer insulative film relative to the chalcogenide material layer.

14. A semiconductor storage device according to claim 12, wherein the adhesion layer and the interfacial layer comprise a material of lower heat conductivity than the plug.

15. A semiconductor storage device according to claim 12, wherein the adhesion layer and the interfacial layer comprise a material of higher resistivity than the plug.

16. A semiconductor storage device according to claim 12, wherein the adhesion layer and the interfacial layer have a film thickness of 0.5 nm or more and 5 nm or less and are formed in contact with the lower surface of the chalcogenide material layer.

17. A semiconductor storage device according to claim 12, wherein the interfacial layer comprises a material containing Si.

18-31. -31. (canceled)