By resorting to first-principles simulations, we unveil the existence of peculiar electronic states in non-stoichiometric amorphous SiN that seem to float in the internal cavities present in the system. These states, if unoccupied, are located in the conduction band along with regular antibonding states. Upon occupation by electrons, they are energetically displaced in the gap of the system or in the upper part of the valence band depending on the stoichiometry and morphology of the cavities, without significant change in their floating nature. These localized floating states are not bound to any specific atom and can be easily charged/uncharged providing insight into the mechanism responsible for the basic function of flash memory devices and guidelines for their design.

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• Chemical bonding
• Electronic structure
• First-principles calculations
• Density functional theory
• Molecular dynamics