Molecular layer depositionIt is a thin film preparation technology based on self limiting surface reactions, which constructs ultra-thin functional thin films with atomic level accuracy on the substrate surface by precisely controlling the deposition process of molecular units layer by layer.1、 The fundamental principle originates from the self limiting reaction mechanism.Molecular layer depositionThe core of thin film growth is achieved through alternating and self limiting chemical reactions between two or more precursors and the substrate surface. Each sedimentation cycle consists of three key steps:
1. A precursor molecule is introduced into the reaction chamber in the form of gas or liquid phase, and undergoes chemical adsorption on the substrate surface to form a monolayer;
2. Remove unreacted precursors and by-products by purging with inert gas;
3. Another precursor is introduced and reacts specifically with the adsorbed first molecule to generate the target thin film material and release small molecule byproducts, which are then removed by blowing to remove excess substances.
The process repeats in a loop, with each round of reaction only occurring at unsaturated surface active sites. When all active sites are occupied, the reaction automatically terminates, ensuring that only one layer or a fixed number of molecular layers are deposited in each cycle, achieving precise control of deposition thickness.
2、 The technical features highlight the advantages. The self limiting reaction mechanism endows high thickness controllability, and by precisely setting the number of cycles, customized preparation of thin films ranging from single molecular layers to hundreds of nanometers can be achieved, with thickness deviation controlled within a very small range. This technology has strong universality for substrate materials, whether it is a planar substrate or a complex three-dimensional structure, surface active sites can participate in the reaction, ensuring uniform coverage of the film.
In addition, it can be carried out under mild conditions, avoiding damage to the substrate material or precursor caused by high temperature and high pressure, and is suitable for sensitive materials with high requirements for thermal stability. By selecting different precursor combinations, various functional thin films can be prepared to meet the performance requirements of different fields.
3、 Application potential drives technological development.Molecular layer depositionIt has shown broad prospects in cutting-edge fields such as insulation layers, anti-corrosion coatings, gas separation membranes, and energy storage electrode modifications in microelectronic devices. Its precise molecular level control capability and extensive material adaptability provide core support for the customized development of functional thin films, and are important technological means to promote innovation in the field of materials science and engineering.