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Taiwan's Tiny RRAM

Island engineers to demonstrate next-generation memory in its smallest footprint yet

3 min read

10 November 2010—Taiwanese researchers say they have invented the smallest nonvolatile resistive RAM (RRAM) architecture yet. RRAM stores bits as a change in the resistance of a memory cell. Big chip firms are intensively investigating RRAM, and the Taiwanese government finds the technology particularly compelling because it might help to reinvigorate the country’s memory industry, which is gradually declining and desperately in need of new technology.

The memory owes its small footprint to its use of a new type of bipolar junction transistor, or BJT, rather than a conventional metal-oxide semiconductor field-effect transistor, or MOSFET. The BJT, which is vertically oriented, drives current through the memory cell to either read a bit or, by changing the cell’s resistance, to write one. In the Taiwanese design, the cell—a film of titanium nitride, titanium, and hafnium oxide sandwiched between two conductors—sits atop the transistor. In previous designs using MOSFETs, the driving transistors were on the sides of the memory cells.

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The Transistor at 75

The past, present, and future of the modern world’s most important invention

2 min read
A photo of a birthday cake with 75 written on it.
Lisa Sheehan

Seventy-five years is a long time. It’s so long that most of us don’t remember a time before the transistor, and long enough for many engineers to have devoted entire careers to its use and development. In honor of this most important of technological achievements, this issue’s package of articles explores the transistor’s historical journey and potential future.

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