ALD:饱和表面控制反应

  • 基板暴露于第一分子前体。
  • 通过化学吸附将第一分子前体保留在表面上。
  • 将第二前体引入表面,其在第一前体的表面上反应。
  • 两种前体之间发生置换反应并形成副产品。
  • 置换反应继续,直到第二前体与第一前体发生反应。
  • 最终反应:前体A+前体B→膜AB+副产品
  • 重复序列以生成所需的膜。

Advantages of Atomic Layer Deposition

  • Atomic layer deposition has several advantages over other techniques due to the actual mechanism used to deposit films.
  • ALD is especially advantageous when film quality or thickness is critical.
  • ALD is also quite effective at coating ultra high aspect ratio substrates or substrates that would be difficult to coat with other thin film techniques.
  • Perfect films:
    • Digital thickness control to the atomic level by depositing film one atomic layer at a time-pinhole-free films, over very large areas
    • Excellent repeatability
    • Wide process windows(no sensitivity to temperature or precursor dose variations)
    • Low-defect density
    • Amorphous or crystalline, depending on substrate and temperature
    • Digital control of sandwiches, hetero-structures, nanolaminates, mixed oxides, graded layers, and doping
    • Insensitivity to particle
    • Standard recipes for oxides, nitrides, metals, and semiconductors
  • Conformal coating :
    • Perfect 3D conformality and 100% step coverage : uniform coatings on flat, inside porous, and around particle samples
    • Flat and smooth coating that copies shape of substrate perfectly
    • Large area thickness uniformity
    • Easy batch scalability
  • Challenging substrates:
    • Gentle deposition process for sensitive substrates, no plasma needed
    • Low temperature deposition possible (RT~400˚C) https://mannapotheke.de/kamagra-oral-jelly/
    • Coats everything, even on teflon
    • Excellent adhesion due to chemical bonds at the first layer
    • Low stress due to molecular self-assembly