ABSTRACT
The quantum dots-based flash memory (QD-flash) is a charge-based memory in which charge carriers are confined within a heterostructure made out of III–V compound semiconductors with large band offsets. There are five key advantages of the QD-flash as compared to the conventional flash memory based on the Si/SiO2 material system: the barrier height can be designed, defect-free interfaces, voltage tenability, writing/erasing does not damage the structure, and hole-based charge storage can be used. Molecular beam epitaxy and metal–organic chemical vapor deposition are epitaxial growth techniques to deposit defect-free semiconductor heterostructures with atomically abrupt interfaces. Self-organized QDs are low-dimensional heterostructures, which confine electrons and/or holes within all three spatial directions. The storage time in self-organized QDs is limited by the carrier emission and capture processes. The key parameter is the barrier height yielding the localization energy of the QDs. Three basic carrier emission mechanisms exist and are observed in QDs: tunneling, thermally assisted tunneling, and thermal activation.
