Pulsed write techniques for magneto-resistive memories

• US 6,538,918 B2
• Filed: 06/17/2002
• Issued: 03/25/2003
• Est. Priority Date: 08/14/2000
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Johnson, William J., Swanson, Richard W., Zhu, Theodore
• Primary Examiner(s): Elms, Richard
• Assistant Examiner(s): NGUYEN, HIEN N
• Application Number:
  US10/174,214
• Publication Number:
  US 20020154539A1
• Time in Patent Office: 281 Days
• Field of Search: 365/158, 365/161, 365/171, 365/145, 365/173, 365/243.5, 365/159
• US Class Current: 365/158
• CPC Class Codes: G11C 11/15 using multiple magnetic layers G11C11/155 takes precedence
• CPC Class Codes: G11C 8/14 Word line organisation; Word line lay-out

Abstract

A magneto-resistive memory that has a shared word line and sense line is disclosed. By providing the shared word line and sense line, the number of relatively large drivers required to drive the word line and sense line currents can be reduced. This reduces the peripheral overhead of the memory, and may increase the overall density and reduce the overall power of the memory.

Claims

1. A method for writing a magneto-resistive bit, the method comprising the steps of:

supplying a word line current adjacent the magneto-resistive bit; and

drawing a sense current from the word line current through at least part of the magneto-resistive bit.

2. A method according to claim 1, wherein the magneto-resistive bit has a word line extending adjacent thereto, and wherein the word line current produces a word line magnetic field component that extends in a first direction relative to the magneto-resistive bit.

3. A method according to claim 2, wherein the sense current produces a sense line magnetic field component that extends in a second direction relative to the magneto-resistive bit, wherein the first direction is orthogonal to the second direction.

4. A method according to claim 3, wherein the drawing step draws a sufficient sense current to write the magneto-resistive bit.

5. A method for operating a magneto-resistive storage device, the magneto-resistive storage device having a magneto-resistive bit with a first end and a second end, a word line extending adjacent the magneto-resistive bit with the word line connected to the first end of the magneto-resistive bit, and a reading circuit coupled to the word line for providing a path for a read sense current to flow to the word line and for sensing the resistive state of the magneto-resistive bit via the read sense current, the method comprising the steps of:

preventing the read circuit from providing a path for the read sense current to flow to the word line;

supplying a word line current to the word line; and

drawing a write sense current from the word line current through at least part of the magneto-resistive bit.

6. A method according to claim 5, further comprising the steps of:

preventing the word line current from being supplied to the word line;

allowing the read circuit to provide a path for the read sense current to flow to the word line;

drawing a read sense current from the word line through at least part of the magneto-resistive bit; and

sensing the resistive state of the magneto-resistive bit using the read sense current.

7. A method according to claim 6, further comprising the step of storing the resistive state of the magneto-resistive bit in a storage element.