Stacey F. Bent, Stanford University, Stanford, CA
Area selective atomic layer deposition (AS-ALD) continues to gain attention as an important method to achieve nanoscale features at the sub-10 nm length scale, especially toward future microelectronics. Tuning the surface chemistry of a substrate can be used to either inhibit or enhance ALD nucleation, leading to selective deposition. A key strategy for AS-ALD is the use of inhibitors, ranging from long-chain self-assembled monolayers to small molecule inhibitors, which can alter the native surface reactivity to block nucleation. This inhibition approach enables good selectivity in AS-ALD of thin films on a variety of substrate materials, including dielectrics and metals. Also critical is the role of the ALD precursor in influencing selectivity. This talk will draw from multiple AS-ALD systems to consider what features of inhibitors and ALD precursor affect selectivity in AS-ALD, and how to design for optimal selectivity. We show that precursor size can have a significant influence on the ability of inhibitors to prevent ALD nucleation. We will also share examples that highlight the influence of other effects beyond molecular size. Finally, we will look to what is next, including recent developments and a discussion of emerging challenges and opportunities for AS-ALD.