Impact of Zirconium Doping on Steep Subthreshold Switching of Negative Capacitance Hafnium Oxide Based Transistors

Abstract

In this work, it is demonstrated that the negative capacitance effect of ferroelectric Hf1-xZrxO2 transistor is highly correlated with Zr doping concentration. A steep subthreshold swing of 40mV/decade, a low off-state leakage current of 190fAm(-1), and a large on/off current ratio of >10(7) can be simultaneously achieved in optimized negative capacitance Hf1-xZrxO2 transistor. Besides, the Zr diffusion issue and non-ferroelectric phases significantly affect the multi-domain switching of polycrystalline Hf1-xZrxO2. Therefore, an appropriate amount of Zr substitution is more favorable for both boosting ferroelectric and implementing the negative capacitance switch.