| Atomic layer deposition（ALD）is an ultrathin film preparation technique,which provides precise control of film thickness with excellent uniformity and conformality based on time-sequenced self-limiting surface half-reactions.Recently,ALD technology has attracted interests in other application fields such as photovoltaics and encapsulations,which require high-throughput and large scale deposition capacity.Among various ALD technique variants,the spatial atomic layer deposition（S-ALD）could effectively meet the requirements of high-throughput and low-cost commercial applications.By increasing the relative velocity between the substrate and the injector,the deposition rate can be increased by 12 orders of magnitude.This thesis focuses on the design and optimization of high-efficiency modular nano-film deposition system based on S-ALD.It is dedicated to achieve faster deposition rate and more uniform film preparation.The main contents of the work include the following aspects:（1）By analyzing the surface adsorption model of the substrate and the single precursor channel adsorption model,we have the factors affecting the film deposition process.These factors include:precursor channel width,precursor channel wall thickness,exhaust channel width,separation gas channel width,and height of micro-gap,substrate movement speed,etc.A high-efficiency modular nano-film deposition system integrated with a modular injector and a linear motor has been designed based on spatial atomic layer deposition technology.（2）The precursor diffusion distribution,film deposition rate,and film growth uniformity are simulated to guide the optimal design of injector structure by coupling the fluid model and the chemical adsorption reaction in the deposition process.Multi-layer gas distribution structure is designed to improve the uniformity of the precursor distribution on the substrate,and the structure and height of each gas-homogenized layer are simulated to analyze the precursor diffusion,film deposition rate,and film growth uniformity to obtain the optimal injector structure.Through the modeling of the reaction injector unit,the film growth process was simulated,and the process parameters such as the height of the micro-gap,the flow rate of the separation gas,the movement speed of the substrate,and the reaction temperature has been studied to obtain the optimum process conditions of the system（3）In order to reduce the inertial impact of the system due to the reciprocating motion with high acceleration,the S-curve is used to optimize the motion trajectory of the substrate,and improve the microstructure of the film.Al2O3 and TiO2 thin film deposition experiments has been performed in the homemade high-efficiency atomic layer deposition system to verify the optimal process conditions obtained from the simulation and test the linear growth and growth uniformity under different moving speeds.The film deposition rate could reach 100nm/min,while keeping the non-uniformity within 3%. |
