HITACHI :

PLEDM®*

PLEDM® is a totally new type of semiconductor memory, intended to overcome an inherent drawback of DRAM's - namely the contradictory requirements of further reduction in cell size and maintenance of S/N (signal-to-noise) ratio large enough to guarantee operation. Conventional DRAM's consist of one transistor and one capacitor cell; the new PLEDM® cell uses instead two transistors to make a 'gain cell' in a smaller area.

The newly developed transistor PLEDTR is stacked onto the gate of a conventional MOSFET and has unique electrical characteristics to allow the PLEDM® cell to work. The integration of one transistor onto the gate of another is a world first. The PLEDM® cell is as small in area as just one transistor - with a read/write time less than 10 nsec. In addition, the gain provides a large signal even in low-voltage operation, leading to reduced power consumption.

*Phase-state Low Electron (hole)-number Drive Memory

Hitachi Corporate Technology Group

PLEDM®*

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