Magnetic random access memory
a random access and memory technology, applied in the field of magnetic random access memory, can solve the problems of difficult to increase the memory capacity, difficult to accurately evaluate the resistance value of only the selected tmr element, and problem of read operation
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
application example
(3) APPLICATION EXAMPLE
[0399] An application example of the device structure of the magnetic random access memory according to the present invention will be described. As a characteristic feature of this application example, TMR elements are stacked at a plurality of stages to increase the memory capacity.
[0400] Assume that a cross-point memory cell array according to the present invention is arranged at one stage. When TMR elements are stacked at n (n is an integer; n≧2) stages, the cell size of a memory cell is 4F2 / n. F is the minimum size of design rule.
[0401]FIG. 26 shows an example of the device structure when TMR elements are stacked at two stages.
[0402] A word line WL1A running in the X-direction is arranged immediately under the TMR elements MTJ at the first stage. Bit lines BL1A, BL2A, and BL3A running in the Y-direction perpendicular to the X-direction are arranged immediately on the TMR elements MTJ at the first stage. The TMR elements MTJ are arranged at the intersect...
application example 1
(1) Application Example 1
[0439] {circle over (1)} Circuit Structure
[0440]FIG. 31 shows the main part of a magnetic random access memory according to Application Example 1 of the present invention.
[0441] As the first characteristic feature of the cell array structure of this example, one terminal of each of a plurality of TMR elements of a read block is commonly connected. As the second characteristic feature, the other terminal of each of a plurality of TMR elements of a read block is independently connected to a read bit line. As the third characteristic feature, one terminal of each of a plurality of TMR elements of a read block is directly connected to a read word line without intervening a read select switch.
[0442] A memory cell array 11 has a plurality of TMR elements 12 arranged in an array in the X- and Y-directions. For example, j TMR elements 12 are arranged in the X-direction, and 4×n TMR elements 12 are arranged in the Y-direction.
[0443] The four TMR elements 12 arran...
application example 2
(3) Application Example 2
[0570]FIG. 38 shows the circuit structure of a magnetic random access memory according to Application Example 2 of the present invention.
[0571] The circuit structure shown in FIG. 38 is an improved example of Detailed Example 1 (FIG. 34) of Application Example 1. As its characteristic feature, a precharge circuit which precharges all read word lines RWLi and all read bit lines RBLi to a precharge potential in advance in read operation is added to Detailed Example 1 of Application Example 1.
[0572] A memory cell array 11 has a plurality of TMR elements 12 arranged in an array in the X- and Y-directions. For example, j TMR elements 12 are arranged in the X-direction, and 4×n TMR elements 12 are arranged in the Y-direction.
[0573] The four TMR elements 12 arranged in the Y-direction form one read block BKik (i=1, . . . , j, k=1, . . . , n). The j read blocks BKik arranged in the X-direction form one row. The memory cell array 11 has n rows. In addition, n read...
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More