新型HfO_2栅介质电特性的理论分析与实验研究

Study on the theory and experiment of electrical characteristics of the novel HfO_2 gate dielectric

对结合NH4F表面预处理和高温退火新型工艺制作的超薄HfO2栅介质MOS电容的C-V特性进行了模拟仿真和实验研究,理论分析的界面态分布与实验结果吻合.利用高频C-V法计算了平带电压漂移量、氧化层内陷阱电荷密度和界面态密度,比较了不同工艺条件下样品的电参数.结果表明NH4F表面预处理和高温退火新型工艺可以显著降低界面态和氧化层陷阱电荷,从而降低栅极漏电流.

The C-V characteristics of the MOS capacitor with ultra thin HfO2 as gate dielectrics pretreated in NH4F and annealed in high temperature are investigated by simulation and experiment. Distribution of interface states is consistent with the experimental results. Shift of the flat-band voltage, density of oxide traps and interface states are calculated. The electrical properties of samples under different processes are compared using high frequency C-V methods. The investigation shows that the novel combination of NH4 F pretreatment and high annealing temperature can reduce interface states and oxide traps dramatically, thus decreasing the gate leakage current.