All metal giant magnetoresistive memory

DETAILED DESCRIPTION According to the present invention, a memory technology is provided which is based on structures which exhibit the property of giant magnetoresistance (GMR), and which overcomes the limitations of conventional memories described above.
The memory arrays of the present invention include individual memory cells comprising GMR thin film structures which store one or more bits of information in their magnetic layers.
Memory access lines are configured to provide random access to each cell in an array.
Selection matrices, control electronics, preamplifiers, and sense amplifiers are all implemented with an all metal device referred to herein as a "transpinnor.
" The transpinnor is a network of GMR thin film structures which has characteristics like both a transistor and a transformer.
The performance of GMR structures improves as the feature size decreases.
In addition, production costs associated with the all metal memories described herein will be dramatically lower than those associated with semiconductor memories for a number of reasons.
First, because the GMR structures of the invention are relatively simple, the number of fabrication steps is significantly reduced as compared to the typical semiconductor process for a similar device (e.
g.
, fewer than 10 versus greater than 30).
Second, the process steps for the all metal architecture of the present invention are carried out at relatively low temperatures (e.
g.
, 200.
degree.
C.
) as compared to the high temperature processing by which semiconductor techniques are characterized (e.
g.
, 800.
degree.
C.
).
Furthermore, hybrid magnetic RAMs involve both processing methods, with subsequent bonding of the semiconductor support electronics with the magnetic memory array.
In contrast, an all-metal magnetic RAM may be fabricated as a single monolithic integrated circuit using a single mask set because the GMR electronics and the GMR memory array are made of the same materials.
In addition, implementation of the memory electronics using transpinnors is advantageous because they can be deposited and patterned at the same time as the memory elements rather than sequentially as with semiconductor process, thereby further reducing the number of process steps required