Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 29: Invited Talk: A. Marent

HL 29.1: Hauptvortrag

Dienstag, 23. März 2010, 14:45–15:15, H17

Quantum Dot Flash Memories: The best of two worlds — •Andreas Marent, Tobias Nowozin, and Dieter Bimberg — Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany

DRAM and Flash memories dominate presently the semiconductor memory market. DRAMs provide fast access times (>10 ns) but the information has to be refreshed every ten milliseconds. Flash memories are non-volatile with storage times of >10 years, but exhibit a slow write speed. Self-organized quantum dots (QDs) might provide a basis for new generations of memories. They can store just a few charge carriers with a retention time depending on the material combination. Furthermore, the carrier relaxation process into QDs is on the order of sub-picoseconds, an important prerequisite for a very fast write time in such memories.

We developed a memory concept based on QDs, which combines the best of DRAM and Flash and enables ultra fast write times (<ns) in combination with a long storage time (>>10 years). We already demonstrated a write time in a QD based memory structure of 6 ns and a hole storage time of 1.6 seconds at room temperature. In addition, we predict a storage time of much more than 10 years using 8-band k*p theory. First prototypes of the QD-Memory with full functionality using InAs-QDs were designed and processed. The performance of the prototypes has been evaluated up to 200 K. This work is partly funded by the DFG, BI 284/29-1 and in the framework of the NanoSci-E+ project QD2D of the European Commision.