By Nidhi DhullMay 29 2024Reviewed by Lexie Corner Atomic layer deposition originated from atomic layer epitaxy, which was introduced in 1970 and initially used in electroluminescent displays. It rapidly revolutionized semiconducting applications, pushing the limits of Moore’s law. Today, ALD is a well-established ultrathin film deposition method, allowing control over the film’s composition, conformity, self-saturation, thickness, and uniformity.
Material Deposition Techniques Various ALD techniques have been developed for material deposition, including thermal , plasma-enhanced , flash-enhanced , and photo-assisted , with TALD and PEALD being the most common. 1 While these ALD techniques produce high-quality films, they have limited application due to the need for special reactors.1
Organic light-emitting diodes and quantum light-emitting diodes , commonly used in displays, suffer erosion by water and oxygen during processing, resulting in defects and short service life. Thin-film encapsulation by ALD enhances the water-oxygen barrier without affecting the flexibility and luminescence of OLEDs. ALD-deposited conformal films of atomic-scale thickness can also stabilize quantum dot QLEDs.
Challenges and Limitations Although ALD is incredibly promising for fabricating highly functional thin films, its commercial application is limited by various challenges, including low growth rate, substantial material waste, disproportionate energy usage, nanoparticle emission risks, and intense processing.3,4
For instance, a recent study in the Journal of Vacuum Science & Technology A explored the use of deep neural networks to optimize ALD processes. Machine learning was employed to predict optimal saturation times in an ALD reactor based on thickness values from a single trial growth, reducing the number of experiments needed to develop novel ALD methods in existing reactors.5
ALD technology has also demonstrated significant potential in biomedical device manufacturing, including micro/nanorobots for diagnosis and drug delivery, sensor coatings, and surface modification of implants.2