Method and apparatus for bipolar memory write-verify
First Claim
1. A method for writing data to a memory device, said method comprising:
- writing a bit of data into a memory cell, wherein said memory cell comprises a bit line and a source line, said writing comprising;
applying a first differential voltage bias across said bit and source lines provided said data bit is a first logic value; and
applying a second differential voltage bias across said bit and source lines provided said data bit is a second logic value, wherein said second differential voltage bias is opposite in polarity to said first differential voltage bias; and
verifying said bit of said memory cell by applying either said first or second differential voltage bias across said bit and source lines depending on the logic value of said bit.
5 Assignments
0 Petitions
Accused Products
Abstract
An advantageous write verify operation for bipolar memory devices is disclosed. The verify operation is performed under the same bias conditions as the write operation. Thus, the verify operation reduces disturb conditions caused when verify operation is performed in opposite bias to write operation. The advantageous write verify operation may be performed with control logic on source and bit lines. In another embodiment, the advantageous write operation is performed with mux coupled to control logic. The mux determines whether verify (0) or verify (1) operation should be performed based on data in a program latch. Moreover, the mux may select bias conditions for read operations based on a register bit. Trim circuits optionally provide guard banding and modify reference voltages for verify operations performed in opposite polarity to normal read operation.
276 Citations
23 Claims
-
1. A method for writing data to a memory device, said method comprising:
writing a bit of data into a memory cell, wherein said memory cell comprises a bit line and a source line, said writing comprising; applying a first differential voltage bias across said bit and source lines provided said data bit is a first logic value; and applying a second differential voltage bias across said bit and source lines provided said data bit is a second logic value, wherein said second differential voltage bias is opposite in polarity to said first differential voltage bias; and verifying said bit of said memory cell by applying either said first or second differential voltage bias across said bit and source lines depending on the logic value of said bit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
13. A method for writing data to a spin-transfer torque magnetic memory (STT-MRAM) device, said method comprising:
-
writing a bit of data into a memory cell, wherein said memory cell comprises a bit line and a source line and a magnetic tunnel junction (MTJ), said writing comprising; applying a first differential voltage bias across said bit and source lines provided said data bit is a first logic value; and applying a second differential voltage bias across said bit and source lines provided said data bit is a second logic value, wherein said second differential voltage bias is opposite in polarity to said first differential voltage bias; and verifying said bit of said memory cell by applying either said first or second differential voltage bias across said bit and source lines depending on the logic value of said bit. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
-
-
21. A method for writing data to a spin-transfer torque magnetic memory (STT-MRAM) device, said method comprising:
-
writing a bit of data into a memory cell, wherein said memory cell comprises a bit line and a source line and a magnetic tunnel junction (MTJ), said writing comprising; applying a first differential voltage bias across said bit and source lines provided said data bit is a first logic value; and applying a second differential voltage bias across said bit and source lines provided said data bit is a second logic value, wherein said second differential voltage bias is opposite in polarity to said first differential voltage bias; and verifying said bit of said memory cell, said verifying comprising; reading said bit of data from a latch; and applying either said first or second differential voltage bias across said bit and source lines depending on the logic value of said bit. - View Dependent Claims (22, 23)
-
Specification