WSe2场效应晶体管的源漏接触特性研究

Research on Source/Drain Contact Characteristics of WSe2 Field Effect Transistors

摘要:

二硒化钨(WSe₂)具有双极导电特性,可以通过外界掺杂或改变源漏金属来调节载流子传输类型,是一类特殊的二维纳米材料,有望在未来集成电路中成为硅(Si)的替代材料。文章采用理论与实验相结合的方式系统分析了WSe₂场效应晶体管中的源漏接触特性对器件导电类型及载流子传输特性的影响,通过制备不同金属作为源漏接触电极的WSe₂场效应晶体管,发现金属/WSe₂接触的实际肖特基接触势垒高低极大地影响了晶体管的开态电流。源漏金属/WSe₂接触特性不仅取决于接触前理想的费米能级差,还受到界面特性,特别是费米能级钉扎效应的影响。

Abstract:

Tungsten diselenide (WSe₂) has ambipolar conductivity characteristics, which can be adjusted by external doping or changing source/drain metals. It is a special type of two dimensional nanomaterials and is expected to replace silicon (Si) in integrated circuits in the future. In this paper, the theory and experiments were combined to systematically analyze the influence of the source/drain contact characteristics of WSe₂ field effect transistor on the conductivity type and carrier transport characteristics of the device. By preparing WSe₂ field effect transistors with different metals as the source/drain contact electrodes, it is found that the actual Schottky contact barrier height of the metal/WSe₂ contact greatly affects the on-state current of the transistor. The source/drain contact characteristics of the metal/WSe₂ depend on the ideal Fermi level difference before contact, and also they will be affected by the interface characteristics, especially the Fermi level pinning effect.