基于低功函数铪电极的Si纳米空气沟道二极管研究

Research on Si-Based Nano-air-channel Diodes with Low Work Function Hafnium Electrodes

基于电子无散射弹道输运的纳米空气沟道二极管具有响应速度快和截止频率高等特点,在毫米波与太赫兹领域中有着巨大的应用潜力。本文研究了以低功函数金属Hf为电极的Si基垂直结构纳米空气沟道二极管的I-V与时间响应特性,并与相同结构的Au电极器件进行了对比。研究发现,相比于先前文献报道较多的截面发射结构,面内发射构型的Hf电极纳米空气沟道二极管发射电流增强了近2倍,5 V电压下达到13.5 mA,并且其I-V曲线线型从符合空间电荷限制电流的V^(3/2)变成了符合F-N场发射的规律。相比于以Au为电极的Si基纳米空气沟道二极管,以Hf为电极的器件发射电流显著提升了近4倍,且器件响应上升沿仅为2 ns,具有超快响应的特性,通过降低器件面积和电容还可进一步提升响应速度。

Nano-air-channel diodes based on electron free ballistic transport have great application potential in millimeter wave and terahertz systems because of the characteristics of high response speed and high cutoff frequency.The I-V characteristics and time response characteristics of Si-based vertical structure nano-air-channel diodes with low work function metal Hf electrodes are studied,and compared with those of the same structure diodes with Au electrodes.Compared with the cross-sectional emission structure reported in previous literature,the emission current of the diodes with in-plane emission structure increases by nearly 2 times,reaching 13.5 mA at 5 V extracting voltage,and the I-V curve shape changes from V^(2/3)space charge limiting law to F-N field emission law.Compared with the Si-based nano-air-channel diodes with Au electrodes,the emission current of the diodes with Hf electrodes significantly increases by nearly 4 times,and the rising edge of them is only 2 ns,which shows an ultra-fast response and it can be further improved by reducing the device area and capacitance.