Fundamentals of Atomic Layer Deposition
Faculty Mentor Information
Elton Graugnard
Abstract
Atomic layer deposition (ALD) is a form of chemical vapor deposition that uses cyclic, sequential gas pulses to deposit thin film using binary self-limiting surface chemistry. ALD is an important process in nanoscale materials and device fabrication because the self-limiting nature of the process results in a high degree of uniformity and conformal film growth. The surface to be coated is exposed to each ALD reactant, referred to as a precursor, separately; the precursors are never present in the reaction chamber at the same time. Each precursor reacts with all available surface sites, limiting each precursor pulse to deposit a certain amount of material. By controlling pulse times, exposure times, purge times, and sample temperature, repeatable layer-by-layer deposition can be achieved. Although a relatively slow process, ALD allows films to be accurately deposited at a uniform thickness with sub-nanometer precision over the entire substrate surface. While invented over 40 years ago, atomic layer deposition is an active area of research, and new discoveries in this field are a key component of the advancement of nanomaterials and nanofabrication.
Fundamentals of Atomic Layer Deposition
Atomic layer deposition (ALD) is a form of chemical vapor deposition that uses cyclic, sequential gas pulses to deposit thin film using binary self-limiting surface chemistry. ALD is an important process in nanoscale materials and device fabrication because the self-limiting nature of the process results in a high degree of uniformity and conformal film growth. The surface to be coated is exposed to each ALD reactant, referred to as a precursor, separately; the precursors are never present in the reaction chamber at the same time. Each precursor reacts with all available surface sites, limiting each precursor pulse to deposit a certain amount of material. By controlling pulse times, exposure times, purge times, and sample temperature, repeatable layer-by-layer deposition can be achieved. Although a relatively slow process, ALD allows films to be accurately deposited at a uniform thickness with sub-nanometer precision over the entire substrate surface. While invented over 40 years ago, atomic layer deposition is an active area of research, and new discoveries in this field are a key component of the advancement of nanomaterials and nanofabrication.