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IBM Solves PCM Problems with Projections

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resistion
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Re: shunt?
resistion   9/3/2015 4:40:32 PM
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I see that the ON current goes through the bulk PCM, but does this solve the Vth drift?

IBM_Research
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Re: shunt?
IBM_Research   9/3/2015 11:27:19 AM
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We cover this in the full paper:

"The resistance of this projection segment is judiciously chosen such that it has only a marginal influence on the write operation (during which the phase transition occurs), but a significant influence on the read operation. This is indeed possible because electrical transport in amorphous phase-change materials is highly nonlinear. At high fields, the amorphous material undergoes the so-called electronic threshold switching, leading to a low-resistive state (ON state). Thus, if during the high-field write process (SET and RESET) the resistance of the projection component is significantly higher than the ON-state resistance of the amorphous region, most of the current will flow through the phase-change segment. During the low-field read process, however, the current bypasses the highly resistive amorphous region and flows through that part of the projection segment that is parallel to it. Hence, the resistance of the device is dominated by the resistance of that part of the projection segment, and thus is a good measure of the amorphous/crystalline phase configuration."

IBM_Research
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Re: shunt?
IBM_Research   9/3/2015 11:24:27 AM
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FYI: The Nature Communications paper is now online here: http://www.nature.com/ncomms/2015/150903/ncomms9181/full/ncomms9181.html

Ron Neale
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Re: shunt?
Ron Neale   9/3/2015 11:18:02 AM
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Resistion: The projection element will be a much higher resistance than the set device in either its crystalline or molten state. There will be some minor shunting, after all it is a parallel resistor. I think as I tried to show in my simple I-V characteristics during read in the high resistance state the non-linear characteristics of the off state make the active device invisible.

resistion
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shunt?
resistion   9/3/2015 10:59:05 AM
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The projection won't shunt the set or reset current?

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