Non-Volatile Ferroelectric FETs Using 5-nm Hf_0.5Zr_0.5O₂ with High Data Retention and Read Endurance for 1T Memory Applications

FeFETs with 5-nm-Thick Hf_0.5Zr_0.5O₂ (HZO) have been demonstrated in memory operations for the ON/OFF current ratio >10⁴ at zero gate voltage and a memory window (MW) of 0.6-0.7 V. A gradual transition of the ferroelectricity with an increasing crystallization temperature for the gate-last process was presented. The excellent data retention are the ∼2×10⁴ ON/OFF ratio and 0.67 V extrapolated to ten years with V_P/E = ±4.8 V. The MW remains >0.2 V after 10₆ cycles for read and vanishes with cycles of 10³-10⁴ for write, which is the bottleneck for ferroelectric (FE)-Type memories. The mechanism of retention and endurance is discussed. The characteristic of this letter is an unaffected coercive-field (1 MV/cm) with scaling FE-HZO down to 5-nm thickness, which is beneficial for reducing the operation voltage. A comparable performance with thick HZO (>5 nm) on high data retention and endurance with low voltage for read is achieved. The ultrathin FE layer proposes a realistic emerging memory for 1T architecture.