Characteristics of SONOS-Type Flash Memory With In Situ Embedded Silicon Nanocrystals

In this paper, silicon-oxide-nitride-oxide-semiconductor (SONOS) devices with embedded silicon nanocrystals (Si-NCs) in silicon nitride using in situ method with multilevel and 2-b/cell operation have been successfully demonstrated. The proposed in situ Si-NC deposition method exhibits the advantages of low cost, simplicity, and compatibility with modern IC processes. SONOS memories with embedded Si-NCs exhibit a significantly improved performance with a large memory window (> 5.5 V), low operating voltage (P/E voltage: V_g = 6 V, V_d = 7 V and V_g = -7 V, V_d = 10 V, respectively), greater tolerable gate and drain disturbance (V_t shift <; 0.2 V), negligible second-bit effect, high P/E speed (after programming time = 10 μs with a 2-V shift of V_t under V_g = V_d = 6 V operation), good retention time (> 10⁸ s for 13% charge loss), and excellent endurance performance (after 10⁴ P/E cycles with a memory window of 3 V).