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使用钼铁和钌等羰基前驱体进行区域选择CVD沉积金属薄膜 使用氨来抑制氧化物表面的成核

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Area selective CVD of metallic films from molybdenum, iron, and ruthenium carbonyl precursors: Use of ammonia to inhibit nucleation on oxide surfaces
Journal of Vacuum Science & Technology A 36, 041507 (2018);

使用钼,铁和钌等羰基前驱体进行区域选择性CVD沉积金属薄膜:使用氨来抑制氧化物表面的成核

Elham Mohimi and Zhejun V. Zhang
  Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, Illinois 61801Sumeng Liu
  Department of Chemistry, University of Illinois at Urbana Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801Justin L. Mallek
  MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420Gregory S. Girolami
  Department of Chemistry, University of Illinois at Urbana Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801John R. Abelsona)
  Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, Illinois 61801
a)Electronic mail: abelson@illinois.edu

ABSTRACT
摘要


The authors demonstrate that the addition of an ammonia coflow during the chemical vapor deposition of MoCxNy, Fe, or Ru thin films at ≤200 °C from the metal carbonyl precursors Mo(CO)6, Fe(CO)5, or Ru3(CO)12 affords area-selective growth: film grows readily on titanium metal or vanadium nitride substrate surfaces, but no nucleation occurs on air-exposed SiO2, TiO2, Al2O3, or MgO within the investigated times of 1–2 h. By contrast, in the absence of ammonia, nucleation and deposition on these oxide surfaces can either be slow or rapid, depending strongly on the oxide surface preparation.

NH3 is also the source of N in MoCxNy, which has a resistivity of 200 μΩ cm and becomes superconducting at a critical temperature of 4 K. The authors hypothesize that the passivating effect of NH3 on oxide surfaces involves site blocking to prevent precursor adsorption, or an acid–base interaction to stabilize surface-bound metal subcarbonyl intermediates, or a combination of these mechanisms. A key finding is that surface selective growth is often crucially dependent on the sample history of the substrate, which must be specified in detail if reproducible results are to be obtained.

        作者论证了,在 ≤200 °C的温度下,使用金属羰基前驱体Mo(CO)6 Fe(CO)5或Ru3(CO)12进行MoCxNy, Fe或Ru等薄膜的化学气相沉积过程中,加入同向氨气流会获得区域选择性生长:薄膜在钛金属或氮化钒衬底表面上容易生长,但在所实验的1-2小时内,在暴露于空气的SiO2、TiO2、Al2O3,或MgO上没有发生成核。相反,在没有氨的情况下,在这些氧化物表面上的成核和沉积可以是缓慢的,也可以或快速的,这在很大程度上取决于氧化物表面的制备情况。NH3也是MoCxNy中N的来源,后者的电阻率为200 μΩ cm,在临界温度为4K时具有超导性。作者假设,NH3对氧化物表面的钝化作用参与了位点阻断以防止前驱体吸附,或者酸-碱的相互作用以稳定表面结合的金属亚羰基中间体,或者是这些机制的组合作用。一个关键的发现是,表面选择性生长通常决定性地取决于基材的样品历史,如果要获得可重复的结果,必须对该基材作出详细说明。

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