Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 30: Quantum dots and wires: Transport properties II

HL 30.3: Talk

Tuesday, February 26, 2008, 14:45–15:00, ER 164

Write/erase time of nanoseconds in quantum dot based memory structures — •Tobias Nowozin, Andreas Marent, Martin Geller, and Dieter Bimberg — Institut fuer Festkoerperphysik, TU Berlin, Hardenbergstr. 36, 10623 Berlin

We have developed a novel charge-storage memory concept based on III-V semiconductor quantum dots (QDs) [1] which has a number of fundamental advantages over conventional Si/SiO₂ floating gate memories (Flash): material-tunable and voltage-tunable barriers for improved intrinsic speed and/or storage time and high endurance. To investigate the potential of this new memory concept we have determined intrinsic write/erase times in memory structures based on InAs/GaAs and GaSb/GaAs QDs using capacitance-voltage spectroscopy. We measured a write time below 15 ns independent of the localization energy (i.e. the storage time) of the QDs. This write time is more than three orders of magnitude faster than in a Flash cell and already below the write time of a dynamic random access memory (DRAM). The erase time was determined to be 42 ns for InAs/GaAs QDs and 1.5 ms for GaSb/GaAs QDs for applied electric fields of 166 kV/cm and 206 kV/cm, respectively. From these results we derive an erase time of 1 ns in GaSb QDs for an electric field of 330 kV/cm.

[1] M. Geller, A. Marent, and D. Bimberg, "A non-volatile memory based on semiconductor nanostructure", CPT patent application, (2006).