Implementation of VMCO area switching cell to VBL architecture

Patent metadata

Field	Value
Publication number	US-10026782-B2
Application number	US-201715633054-A
Country	US
Kind code	B2
Filing date	Jun 26, 2017
Priority date	Feb 16, 2016
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

Systems and methods for improving performance of a non-volatile memory that utilizes a Vacancy Modulated Conductive Oxide (VMCO) structure are described. The VMCO structure may include a layer of amorphous silicon (e.g., a Si barrier layer) and a layer titanium oxide (e.g., a TiO2 switching layer). In some cases, the VMCO structure or VMCO stack may use bulk switching or switching O-ion movements across an area of the VMCO structure, as opposed to switching locally in a constriction of vacancy formed filamentary path. A VMCO structure may be partially or fully embedded within a word line layer of a memory array.

First claim

What is claimed is:

1. A memory structure, comprising:
a vertical bit line arranged orthogonal to a substrate;
a second word line layer;
a first dielectric layer;
a first word line layer, the second word line layer arranged above the first dielectric layer, the first dielectric layer arranged above the first word line layer;
a first memory cell connected to the vertical bit line, the first memory cell arranged within a recessed portion of the first word line layer arranged below the first dielectric layer, the first memory cell includes a first layer of amorphous silicon and a first layer of titanium oxide; and
a second memory cell connected to the vertical bit line, the second memory cell arranged within a recessed portion of the second word line layer arranged above the first dielectric layer, the second memory cell includes a second layer of amorphous silicon and a second layer of titanium oxide, the recessed portion of the second word line layer is arranged above the recessed portion of the first word line layer.

2. The memory structure of claim 1 , wherein:
the first layer of amorphous silicon is arranged between the first layer of titanium oxide and the first dielectric layer.

3. The memory structure of claim 1 , wherein:
the first layer of titanium oxide is arranged between the first layer of amorphous silicon and the first dielectric layer.

4. The memory structure of claim 1 , wherein:
the first layer of amorphous silicon is arranged between the first layer of titanium oxide and the vertical bit line.

5. The memory structure of claim 1 , wherein:
the first layer of titanium oxide is arranged between the first layer of amorphous silicon and the vertical bit line.

6. The memory structure of claim 1 , wherein:
the recessed portion of the second word line layer is completely filled by the second layer of amorphous silicon and the second layer of titanium oxide.

7. The memory structure of claim 1 , wherein:
the first word line layer comprises a word line material; and
the first dielectric layer comprises a dielectric material.

8. The memory structure of claim 7 , wherein:
the word line material comprises titanium nitride; and
the dielectric material comprises silicon dioxide.

9. The memory structure of claim 1 , wherein:
the recessed portion of the first word line layer is completely filled by the first layer of amorphous silicon and the first layer of titanium oxide.

10. A memory structure, comprising:
a vertical bit line arranged orthogonal to a substrate;
a first memory cell arranged between a first word line and the vertical bit line, the first memory cell includes a first portion of a layer of amorphous silicon and a first portion of a layer of titanium oxide, the first memory cell is arranged within a recessed portion of a first word line layer corresponding with the first word line; and
a second memory cell arranged between a second word line and the vertical bit line, the second word line is arranged above the first word line, the second memory cell includes a second portion of the layer of amorphous silicon and a second portion of the layer of titanium oxide, the first portion of the layer of amorphous silicon does not directly contact the second portion of the layer of amorphous silicon, the first portion of the layer of titanium oxide does not directly contact the second portion of the layer of titanium oxide, the second memory cell is arranged within a recessed portion of the second word line layer corresponding with the second word line, the recessed portion of the second word line layer is arranged above the recessed portion of the first word line layer.

11. The memory structure of claim 10 , wherein:
the first portion of the layer of amorphous silicon is arranged between the first portion of the layer of titanium oxide and the vertical bit line.

12. The memory structure of claim 10 , wherein:
the first portion of the layer of titanium oxide is arranged between the first portion of the layer of amorphous silicon and the vertical bit line.

13. The memory structure of claim 10 , wherein:
the vertical bit line comprises tungsten; and
the first word line comprises titanium nitride.

14. The memory structure of claim 10 , wherein:
the recessed portion of the first word line layer includes the first portion of the layer of amorphous silicon and the first portion of the layer of titanium oxide.

15. The memory structure of claim 10 , wherein:
the recessed portion of the second word line layer includes the second portion of the layer of amorphous silicon and the second portion of the layer of titanium oxide.

16. A memory structure, comprising:
a vertical bit line arranged orthogonal to a substrate;
a first word line layer arranged below a second word line layer
a first memory cell connected to the vertical bit line, the first memory cell arranged within a recessed portion of the first word line layer, the first memory cell includes a first layer of amorphous silicon and a first layer of titanium oxide; and
a second memory cell connected to the vertical bit line, the second memory cell arranged within a recessed portion of the second word line layer, the second memory cell includes a second layer of amorphous silicon and a second layer of titanium oxide, the recessed portion of the second word line layer is arranged above the recessed portion of the first word line layer.

17. The memory structure of claim 16 , wherein:
the first layer of amorphous silicon is arranged between the first layer of titanium oxide and the vertical bit line.

18. The memory structure of claim 16 , wherein:
the first layer of titanium oxide is arranged between the first layer of amorphous silicon and the vertical bit line.

Assignees

• Sandisk Technologies Llc

Inventors

• Tanaka Yoichiro
• Chen Yangyin
• Fu Chu-Chen
• Petti Christopher

Classifications

• H10W20/4441

  the principal metal being a refractory metal · CPC title

• H10W20/43

  Layouts of interconnections · CPC title

• G11C2213/51

  Structure including a barrier layer preventing or limiting migration, diffusion of ions or charges or formation of electrolytes near an electrode · CPC title

• G11C2213/79

  Array wherein the access device being a transistor · CPC title

• G11C13/0026

  Bit-line or column circuits · CPC title