Non-volatile memory arrays comprising rail stacks with a shared diode component portion for diodes of electrically isolated pillars

• US 8,154,005 B2
• Filed: 06/13/2008
• Issued: 04/10/2012
• Est. Priority Date: 06/13/2008
• Status: Expired due to Fees

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk 3D LLC (Western Digital Corporation)
• Inventors: Hsia, Kang-Jay, Petti, Christopher J., Li, Calvin K.
• Primary Examiner(s): LOKE, STEVEN HO YIN
• Assistant Examiner(s): Ziskind, David
• Application Number:
  US12/139,435
• Publication Number:
  US 20090309089A1
• Time in Patent Office: 1,397 Days
• Field of Search: 257/530, 257/656, 257/5, 438/138, 365/148, 365/153, 365/163
• US Class Current: 257/5
• CPC Class Codes: H10B 20/10 ROM devices comprising bipolar components
• CPC Class Codes: H10B 63/20 comprising selection components having two electrodes, e.g. diodes

Abstract

An integrated circuit including vertically oriented diode structures between conductors and methods of fabricating the same are provided. Two-terminal devices such as passive element memory cells can include a diode steering element in series with an antifuse and/or other state change element. The devices are formed using pillar structures at the intersections of upper and lower sets of conductors. The height of the pillar structures are reduced by forming part of the diode for each pillar in a rail stack with one of the conductors. A diode in one embodiment can include a first diode component of a first conductivity type and a second diode component of a second conductivity type. A portion of one of the diode components is divided into first and second portions with one on the portions being formed in the rail stack where it is shared with other diodes formed using pillars at the rail stack.

Claims

1. An integrated circuit device, comprising:

a first conductor elongated in a first direction above a substrate;

a first set of strips including a second conductor and a first portion of a first diode component, the first set of strips elongated in a second direction above the substrate, the second direction being substantially orthogonal to the first direction; and

a pillar formed between the first conductor and the first set of strips, the pillar including a second portion of the first diode component, a second diode component, and a state change element in series between the first conductor and the first set of strips, the first portion of the first diode component and the second portion of the first diode component both comprising an intrinsic layer of polysilicon;

wherein the first portion of the first diode component extends in the second direction beyond the pillar.

2. The integrated circuit device of claim 1, wherein:

the second diode component comprises a heavily doped silicon region of a first conductivity type.

3. The integrated circuit device of claim 2, wherein the first set of strips further comprises:

a heavily doped polysilicon region of a second conductivity type formed between the second conductor and the first portion of the first diode component.

4. The integrated circuit device of claim 1, wherein the state change element is an antifuse.

5. The integrated circuit device of claim 4, wherein the antifuse is formed between the second portion of the first diode component and the second diode component.

6. An integrated circuit device according to claim 1, wherein the pillar further comprises an antifuse in series with the first diode component, the second diode component and the state change element.

7. An integrated circuit device according to claim 1, wherein:

the first conductor, the second conductor, the first portion of the first diode component, the state change element, the second portion of the first diode component and the second diode component form at least one non-volatile memory cell.

8. An integrated circuit device according to claim 7, wherein the at least one non-volatile memory cell is a field-programmable re-writable memory cell.

9. An integrated circuit device according to claim 7, wherein:

the integrated circuit includes a monolithic three-dimensional non-volatile memory array;

the at least one non-volatile memory cell is formed at a first memory level of the monolithic three-dimensional non-volatile memory array; and

the integrated circuit includes at least one additional memory level.

10. An integrated circuit device, comprising:

a first conductor elongated in a first direction above a substrate;

a first set of strips including a second conductor and a first portion of a first diode component, the first set of strips elongated in a second direction above the substrate, the second direction being substantially orthogonal to the first direction; and

a pillar formed between the first conductor and the first set of strips, the pillar including a second portion of the first diode component, a second diode component, and a state change element in series between the first conductor and the first set of strips, the first portion of the first diode component and the second portion of the first diode component both comprising a layer of lightly doped polysilicon of a first conductivity type, the second diode component comprising a heavily doped polysilicon region of a second conductivity type, the second conductivity type being opposite to the first conductivity type;

wherein the first portion of the first diode component extends in the second direction beyond the pillar.

11. The integrated circuit device of claim 10, wherein the first set of strips further comprises:

a heavily doped polysilicon region of the first conductivity type formed between the second conductor and the first portion of the first diode component.

12. The integrated circuit device of claim 10, wherein the state change element is an antifuse.

13. The integrated circuit device of claim 12, wherein the antifuse is formed between the second portion of the first diode component and the second diode component.

14. An integrated circuit device according to claim 10, wherein the pillar further comprises an antifuse in series with the first diode component, the second diode component and the state change element.

15. An integrated circuit device according to claim 10, wherein:

the first conductor, the second conductor, the first portion of the first diode component, the state change element, the second portion of the first diode component and the second diode component form at least one non-volatile memory cell.

16. An integrated circuit device according to claim 15, wherein the at least one non-volatile memory cell is a field-programmable re-writable memory cell.

17. An integrated circuit device according to claim 15, wherein:

the integrated circuit includes a monolithic three-dimensional non-volatile memory array;

the at least one non-volatile memory cell is formed at a first memory level of the monolithic three-dimensional non-volatile memory array; and

the integrated circuit includes at least one additional memory level.