Profiling of Nitride-Trap-Energy Distribution in SONOS Flash Memory by Using a Variable-Amplitude Low-Frequency Charge-Pumping Technique

A variable-amplitude low-frequency charge-pumping technique is proposed to characterize the nitride-trap energy and spatial distributions in SONOS Flash memory cells. A numerical model based on Shockley-Read-Hall-like electron tunneling capture is used to correlate a charge-pumping current with the nitride-trap energy and position. By changing the frequency and pulse amplitude in charge-pumping measurement, a nitride-trap density, as a function of the trap position and energy, can be extracted.