Scappucci Giordano, Klesse Wolfgang M, Yeoh LaReine A, Carter Damien J, Warschkow Oliver, Marks Nigel A, Jaeger David L, Capellini Giovanni, Simmons Michelle Y, Hamilton Alexander R
School of Physics, University of New South Wales, Sydney, 2052, Australia.
1] Department of Chemistry, Curtin University, Perth WA 6845, Australia. [2] Nanochemistry Research Institute, Curtin University, Perth WA 6845, Australia.
Sci Rep. 2015 Aug 10;5:12948. doi: 10.1038/srep12948.
Extending chip performance beyond current limits of miniaturisation requires new materials and functionalities that integrate well with the silicon platform. Germanium fits these requirements and has been proposed as a high-mobility channel material, a light emitting medium in silicon-integrated lasers, and a plasmonic conductor for bio-sensing. Common to these diverse applications is the need for homogeneous, high electron densities in three-dimensions (3D). Here we use a bottom-up approach to demonstrate the 3D assembly of atomically sharp doping profiles in germanium by a repeated stacking of two-dimensional (2D) high-density phosphorus layers. This produces high-density (10(19) to 10(20) cm(-3)) low-resistivity (10(-4)Ω · cm) metallic germanium of precisely defined thickness, beyond the capabilities of diffusion-based doping technologies. We demonstrate that free electrons from distinct 2D dopant layers coalesce into a homogeneous 3D conductor using anisotropic quantum interference measurements, atom probe tomography, and density functional theory.
要将芯片性能提升至当前小型化极限之外，需要能与硅平台良好集成的新材料和新功能。锗符合这些要求，已被提议用作高迁移率沟道材料、硅基集成激光器中的发光介质以及用于生物传感的等离子体导体。这些不同应用的共同之处在于需要在三维空间（3D）中实现均匀的高电子密度。在此，我们采用自下而上的方法，通过重复堆叠二维（2D）高密度磷层来展示锗中原子级尖锐掺杂分布的三维组装。这产生了具有精确界定厚度的高密度（10¹⁹至10²⁰ cm⁻³）、低电阻率（10⁻⁴Ω·cm）的金属锗，这是基于扩散的掺杂技术所无法实现的。我们使用各向异性量子干涉测量、原子探针断层扫描和密度泛函理论证明，来自不同二维掺杂层的自由电子聚合成了均匀的三维导体。
