CSE 40547/60547: Computing at the Nanoscale
Much
of the work that we have discussed in class has focused on the performance of
single or a handful of devices. Ultimately, if an emerging technology is to have impact and
enter the marketplace, large-scale manufacturing and reliability issues must be
addressed. This paper talks about
such efforts performed by researchers from Freescale concerning an
implementation of MRAM. Read ÒDemonstrated
Reliability of 4-Mb MRAMÓ by Nahas, et. al. and answer the following
questions. If you complete this assignment – and your score is better
than your score for either HW1, 2, 3, 5, or 6 – you can replace that
score with this score.
Question
1
What
type of MRAM are the authors of the paper testing? Briefly explain.
Question
2
Explain
how (both physically and logically), time dependent dielectric breakdown can
lead to less reliable MRAM devices.
Note that a good answer should also consider the frequency of MRAM bit
ÒstressesÓ.
Question
3
Explain
how (both physically and logically), time dependent resistance drift can lead
to less reliable MRAM devices.
Question
4
The
authors indicate that time dependent resistance drift, should not preclude an
MRAM array from being reliable for > 10 years. Obviously, a part was not continuously stressed/tested for
10 years. How can they make this
claim? What experiments/testing
were done to support this claim?
Question
5
The
yoked copper wires (that make up word/bit lines) were also stressed. Explain what mechanism would most
likely cause such a wire to ÒfailÓ.