McClellan Connor J, Yalon Eilam, Smithe Kirby K H, Suryavanshi Saurabh V, Pop Eric
Electrical Engineering, Stanford University, Stanford, California 94305, United States.
Materials Science and Engineering, Stanford University, Stanford, California 94305, United States.
ACS Nano. 2021 Jan 26;15(1):1587-1596. doi: 10.1021/acsnano.0c09078. Epub 2021 Jan 6.
Semiconductors require stable doping for applications in transistors, optoelectronics, and thermoelectrics. However, this has been challenging for two-dimensional (2D) materials, where existing approaches are either incompatible with conventional semiconductor processing or introduce time-dependent, hysteretic behavior. Here we show that low-temperature (<200 °C) substoichiometric AlO provides a stable -doping layer for monolayer MoS, compatible with circuit integration. This approach achieves carrier densities >2 × 10 cm, sheet resistance as low as ∼7 kΩ/□, and good contact resistance ∼480 Ω·μm in transistors from monolayer MoS grown by chemical vapor deposition. We also reach record current density of nearly 700 μA/μm (>110 MA/cm) along this three-atom-thick semiconductor while preserving transistor on/off current ratio >10. The maximum current is ultimately limited by self-heating (SH) and could exceed 1 mA/μm with better device heat sinking. With their 0.1 nA/μm off-current, such doped MoS devices approach several low-power transistor metrics required by the international technology roadmap.
半导体在晶体管、光电子学和热电学应用中需要稳定的掺杂。然而,这对于二维(2D)材料来说一直具有挑战性,因为现有的方法要么与传统半导体加工不兼容,要么会引入随时间变化的滞后行为。在此,我们表明低温(<200°C)亚化学计量的AlO为单层MoS提供了一个稳定的掺杂层,与电路集成兼容。这种方法在通过化学气相沉积生长的单层MoS晶体管中实现了载流子密度>2×10 cm、低至约7 kΩ/□的薄层电阻以及约480 Ω·μm的良好接触电阻。我们还在这种三原子厚的半导体上达到了近700 μA/μm(>110 MA/cm)的创纪录电流密度,同时保持晶体管的开/关电流比>10。最大电流最终受自热(SH)限制,通过更好的器件散热,电流可能超过l mA/μm。凭借其0.1 nA/μm的关断电流,这种掺杂的MoS器件接近国际技术路线图要求的几个低功耗晶体管指标。