Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States.
NG Next, Northrop Grumman Corporation , Redondo Beach , California 90278 , United States.
ACS Appl Mater Interfaces. 2019 Apr 3;11(13):12777-12785. doi: 10.1021/acsami.9b00306. Epub 2019 Mar 21.
Metal-semiconductor contact has been a critical topic in the semiconductor industry because it influences device performance remarkably. Conventional metals have served as the major contact material in electronic and optoelectronic devices, but such a selection becomes increasingly inadequate for emerging novel materials such as two-dimensional (2D) materials. Deposited metals on semiconducting 2D channels usually form large resistance contacts due to the high Schottky barrier. A few approaches have been reported to reduce the contact resistance but they are not suitable for large-scale application or they cannot create a clean and sharp interface. In this study, a chemical vapor deposition (CVD) technique is introduced to produce large-area semiconducting 2D material (2H MoTe) planarly contacted by its metallic phase (1T' MoTe). We demonstrate the phase-controllable synthesis and systematic characterization of large-area MoTe films, including pure 2H phase or 1T' phase, and 2H/1T' in-plane heterostructure. Theoretical simulation shows a lower Schottky barrier in 2H/1T' junction than in Ti/2H contact, which is confirmed by electrical measurement. This one-step CVD method to synthesize large-area, seamless-bonding 2D lateral metal-semiconductor junction can improve the performance of 2D electronic and optoelectronic devices, paving the way for large-scale 2D integrated circuits.
金属-半导体接触一直是半导体行业的一个关键课题，因为它显著影响着器件性能。传统金属一直是电子和光电子器件中主要的接触材料，但对于二维（2D）材料等新兴新型材料，这种选择变得越来越不合适。由于肖特基势垒较高，沉积在半导体 2D 沟道上的金属通常会形成大电阻接触。已经有一些报道的方法可以降低接触电阻，但它们不适合大规模应用，或者不能形成干净、锐利的界面。在这项研究中，介绍了一种化学气相沉积（CVD）技术，用于生产大面积的半导体 2D 材料（2H MoTe），其金属相（1T' MoTe）与之平面接触。我们展示了大面积 MoTe 薄膜的相可控合成和系统表征，包括纯 2H 相或 1T'相，以及 2H/1T' 面内异质结构。理论模拟表明，2H/1T'结中的肖特基势垒比 Ti/2H 接触中的肖特基势垒低，这通过电测量得到了证实。这种一步 CVD 方法合成大面积、无缝键合的 2D 横向金属-半导体结，可以提高 2D 电子和光电子器件的性能，为大规模 2D 集成电路铺平道路。
