A new method for characterizing the evolution of oxide charge (Q T ) generation during program/erase (P/E) cycles is developed. The concentration of Q T can be separated from the floating gate charge (O FG ) by statistically analyzing the distribution of transconductance reduction (ΔG m,max ) after P/E cycles. The effect of the number and position of discrete Q T the distribution of ΔG m,max is studied. The cycling dependence of the Qj generation is given by a fractional equation that includes a power of the number of P/E cycles in the denominator. For fewer than 30k cycles, the equation can be simplified as a power-law equation in the number of cycles with a power factor of 0.58. For more than 30k cycles, the Q T generation gradually goes to a plateau value Q 0 = 1.5 × 10 20 cm -3 . It is indicated that the Q T -generation is limited by the concentration of inherent weak bonding points inside SiO 2 or the Si/SiO 2 interface. The temperature dependence of the Q T generation is also provided. The activation energy (E A ) of the Q T generation is approximately 0.1 eV, which is compatible with the E A value of electron traps creation in SiO 2 .
- NAND flash memory
- Oxide charge