Non-volatile memory having 3D array of read/write elements with efficient decoding of vertical bit lines and word lines

• US 8,547,720 B2
• Filed: 06/01/2011
• Issued: 10/01/2013
• Est. Priority Date: 06/08/2010
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk 3D LLC (Western Digital Corporation)
• Inventors: Samachisa, George, Fasoli, Luca, Higashitani, Masaaki, Scheuerlein, Roy Edwin
• Primary Examiner(s): Ho, Hoai V
• Application Number:
  US13/151,224
• Publication Number:
  US 20110299314A1
• Time in Patent Office: 853 Days
• Field of Search: 365/51, 365/148
• US Class Current: 365/51
• CPC Class Codes: G11C 13/003 Cell access
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 2213/71 Three dimensional array
• CPC Class Codes: H10B 63/20 comprising selection components having two electrodes, e.g. diodes
• CPC Class Codes: H10B 63/845 the switching components being connected to a common vertical conductor
• 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 70/235 between different crystalline phases, e.g. cubic and hexagonal
• CPC Class Codes: H10N 70/24 based on migration or redistribution of ionic species, e.g. anions, vacancies
• CPC Class Codes: H10N 70/245 the species being metal cations, e.g. programmable metallization cells
• CPC Class Codes: H10N 70/823 adapted for essentially horizontal current flow, e.g. bridge type devices
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe
• CPC Class Codes: H10N 70/8833 Binary metal oxides, e.g. TaOx
• CPC Class Codes: H10N 70/8845 Carbon or carbides

Abstract

A three-dimensional array of memory elements is formed across multiple layers of planes positioned at different distances above a semiconductor substrate. The memory elements reversibly change a level of electrical conductance in response to a voltage difference being applied across them. The three-dimensional array includes a two-dimensional array of pillar lines from the substrate through the multiple layers of planes. A first set of pillar lines acts as local bit lines for accessing the memory elements together with an array of word lines on each plane. A second set of pillar lines is connected to the word lines. An array of metal lines on the substrate is switchable connected to the pillar lines to provide access to the first and second sets of pillar lines, thereby to provide access respectively to the bit lines and word lines of the three-dimensional array.

Claims

1. A memory including memory elements arranged in a three-dimensional pattern defined by rectangular coordinates having x, y and z-directions and with a plurality of parallel planes stacked in the z-direction, the memory further comprising:

a plurality of first conductive lines elongated in the z-direction through the plurality of planes and arranged in a two-dimensional rectangular array of rows in the x-direction and columns in the y-direction, wherein said plurality of first conductive lines is partitioned into first and second sets of first conductive lines;

a plurality of second conductive lines elongated in the x-direction across individual planes and spaced apart in the y-direction between and separated from the plurality of first conductive lines in the individual planes, wherein the first and second conductive lines cross adjacent each other at a plurality of locations across the individual planes;

a plurality of non-volatile re-programmable memory elements individually connected between the first set of first conductive lines and second conductive lines adjacent the crossings thereof at a first set of the plurality of locations;

a plurality of connectors individually connected between the second set of first conductive lines and second conductive lines adjacent the crossings thereof at a second set of the plurality of locations;

a plurality of third conductive lines partitioned into first and second groups of third conductive lines; and

a first group of select devices arranged to switch a selected row of first conductive lines in the x-direction to the first set of third conductive lines; and

a second group of select devices arranged to switch a selected set of the plurality of second conductive lines to respective second set of third conductive lines; and

wherein the select devices each has a source terminal and a drain terminal that are aligned with the two-dimensional array of first conductive lines in the x-y plane; and

wherein the source and drain terminal of each select device are aligned diagonally in the x-y plane.

2. The memory as in claim 1, wherein:

each adjacent pair of the second conductive lines are disposed around a corresponding row of first conductive lines in the x-direction for operating exclusively therewith.

3. The memory as in claim 1, wherein the selected set of the plurality of second conductive lines includes adjacent pairs of the second conductive lines that are disposed around the selected row of first conductive lines at all of the plurality of planes.

4. The memory of claim 1, wherein

the third conductive lines are elongated in the y-direction,

the select devices are arranged to make those of the first conductive lines aligned in the x-direction connectable with selected ones of the plurality of third conductive lines, and

a plurality of control lines extending in the x-direction and individually connected with a plurality of the select devices aligned in the x-direction to enable connection of a plurality of first conductive lines aligned in the x-direction with different ones of the third conductive lines.

5. The memory as in claim 1, wherein the plurality of select devices and the plurality of third conductive lines are formed in a semiconductor substrate and the plurality of planes are formed as a stack over the semiconductor substrate.

6. The memory as in claim 5, wherein individual third conductive lines are each positioned between adjacent columns of first conductive lines across the x-direction in the x-y plane.

7. The memory as in claim 5, wherein a row of first conductive lines are simultaneously switched by two rows of adjacent select devices to different ones of the third conductive lines.

8. The memory as in claim 5, wherein individual third conductive lines are each positioned in coincident with columns of first conductive lines across the x-direction in the x-y plane.

9. The memory as in claim 8, wherein the source and drain terminal of each select device are aligned in the y-direction.

10. The memory as in claim 1, wherein:

the plurality of select devices are formed in a semiconductor substrate;

the plurality of planes are formed as a stack over the semiconductor substrate; and

the plurality of third conductive lines are formed over the stack.

11. The memory as in claim 10, further comprising:

vertical interconnecting conductive lines through the stack between individual select devices and respective third conductive lines.

12. The memory as in claim 1, wherein the individual memory elements are characterized by including a material that reversibly changes its level of electrical conductance between at least first and second stable levels in response to an electrical stimulus being applied through the first and second conductive lines between which the memory element is connected.