A novel nonvolatile memory based on self-organized quantum dots

A novel type of memory based on self-organized quantum dots (QDs) is presented, which merges the advantages of the most important semiconductor memories, the dynamic random access memory (DRAM) and the Flash. A nonvolatile memory with fast access times (<10ns) and good endurance (>1015>1015 write/erase cycles) as an ultimate solution seems possible. A storage time of 1.6 s at 300 K in InAs/GaAsInAs/GaAs QDs with an additional Al0.9Ga0.1AsAl0.9Ga0.1As barrier is demonstrated and a retention time of 106106 years is predicted for GaSb QDs in an AlAs matrix. A minimum write time of 6 ns is obtained for InAs/GaAs QDs. This value is already in the order of the access time of a DRAM cell and at the moment limited by the RC low pass of the device. An erase time of milliseconds is shown in first measurements on GaSb/GaAsGaSb/GaAs QDs at 100K. Faster write/erase times below 1ns even at room temperature are expected for improved device structures.