Effects of interface trap generation and annihilation on the data retention characteristics of flash memory cells

It is revealed that the interface trap generation rate increases by Fowler-Nordheim current stressing on the tunnel oxide as the channel width of shallow-trench isolation (STI)-isolated NAND flash cells shrinks. Furthermore, we argue that the interface trap annihilation phenomenon during retention mode becomes a major failure mechanism of the data retention characteristics of sub-100-nm cells in addition to the conventional charge loss mechanism. A new interface trap analysis method using the hysteresis of the I_d--V_g curve is proposed and shows that the interface traps consist of fast traps and slow traps.