Large bit-per-cell three-dimensional mask-programmable read-only memory

• US 8,564,070 B2
• Filed: 05/24/2010
• Issued: 10/22/2013
• Est. Priority Date: 05/24/2010
• Status: Expired due to Fees

• Current Assignee: ChengDu HaiCun IP Technology LLC, Guobiao Zhang
• Original Assignee: ChengDu HaiCun IP Technology LLC, Guobiao Zhang
• Inventors: Zhang, Guobiao
• Primary Examiner(s): Such, Matthew W
• Assistant Examiner(s): Naraghi, Ali
• Application Number:
  US12/785,621
• Publication Number:
  US 20110284814A1
• Time in Patent Office: 1,247 Days
• Field of Search: 257/390, 257/50, 257/209, 257529-530, 257/E27.006, 365/148
• US Class Current: 257/390
• CPC Class Codes: G11C 17/10 in which contents are determined during manufacturing by a predetermined arrangement of coupling elements, e.g. mask-programmable ROM
• CPC Class Codes: H01L 28/20 Resistors
• CPC Class Codes: H01L 29/868 PIN diodes
• CPC Class Codes: H10B 20/00 Read-only memory [ROM] devices

Abstract

A large bit-per-cell three-dimensional mask-programmable read-only memory (3D-MPROM_B) is disclosed. It can achieve large bit-per-cell (e.g. 4-bpc or more). 3D-MPROM_B can be realized by adding resistive layer(s) or resistive element(s) to the memory cells.

Claims

1. A three-dimensional mask-programmable read-only memory including a plurality of mask-programmable read-only memory levels stacked above and coupled to a semiconductor substrate, comprising:

a first memory cell comprising a first resistive layer;

a second memory cell comprising a second resistive layer;

a third memory cell comprising said first and second resistive layers;

wherein each of said first, second and third memory cells comprises a quasi-conduction layer, and said first, second and third memory cells have different current-voltage characteristics.

2. The three-dimensional mask-programmable read-only memory according to claim 1, wherein selected one of said first and second resistive layers has a resistance comparable to or larger than said quasi-conduction layer at threshold current.

3. The three-dimensional mask-programmable read-only memory according to claim 1, wherein selected one of said first and second resistive layers is above said quasi-conduction layer.

4. The three-dimensional mask-programmable read-only memory according to claim 1, wherein selected one of said first and second resistive layers is in said quasi-conduction layer.

5. The three-dimensional mask-programmable read-only memory according to claim 1, wherein selected one of said first and second resistive layers is below said quasi-conduction layer.

6. The three-dimensional mask-programmable read-only memory according to claim 1, wherein selected one of said first and second resistive layers comprises at least one semiconductor layer.

7. The three-dimensional mask-programmable read-only memory according to claim 1, wherein selected one of said first and second resistive layers comprises at least one dielectric layer.

8. A three-dimensional mask-programmable read-only memory including a plurality of mask-programmable read-only memory levels stacked above and coupled to a semiconductor substrate, comprising:

a first memory cell comprising a first quasi-conduction layer;

a second memory cell comprising a second quasi-conduction layer, said second quasi-conductor layer comprising more concentration of at least one resistive element than said first quasi-conductor layer;

wherein the memory cells in said memory have N (N>

2) states, and memory cells in different states have different current-voltage characteristics.

9. The three-dimensional mask-programmable read-only memory according to claim 8, wherein the material in said second quasi-conduction layer has a higher resistivity than the material in said first quasi-conduction layer.

10. The three-dimensional mask-programmable read-only memory according to claim 8, wherein the material in said second quasi-conduction layer has a larger bandgap than the material in said first quasi-conduction layer.

11. The three-dimensional mask-programmable read-only memory according to claim 8, wherein said resistive element is selected from a group of elements consisting of oxygen, nitrogen and carbon.

12. The three-dimensional mask-programmable read-only memory according to claim 8, further comprising a third memory cell, wherein said third memory cell comprises at least a resistive layer.