Charge-Trap-Flash (CTF) is a technology for memory cells comparable to floating gate. The advantage of this technology is that the individual memory cells of the CTF memory do not influence each other, as is the case with floating gate memory, and that a higher memory density can be achieved with CTF technology.
In terms of structure, CTF technology is similar to floating gate technology. Only the floating gate is replaced by the charge trap layer. The electrons and electron holes are held on the charge trap layer made of silicon nitride. This layer is separated from the silicon substrate by a thin oxide layer, the tunnel oxide. Since the control gate has a higher positive potential, the electrons pass through the channel between drain and source and through the tunnel oxide layer onto the charge trap layer, from where they cannot flow away.
CTF technology is mainly used for NAND flashes.