Topographically selective atomic layer deposition within trenches enabled by an amorphous carbon inhibition layer

To meet the demands for more advanced computer chips, creating devices with advanced 3D architectures is becoming commonplace in the semiconductor industry. To ensure alignment between the different layers, the bottom-up technique of area-selective deposition (ASD) is promising. However, ASD may not always be feasible depending on the various surface chemistries present during manufacturing of complex semiconductor devices. Topographically selective deposition (TSD) is emerging as an alternative, focusing on differences in surface orientation rather than chemical properties. This work demonstrates a TSD supercycle approach in which atomic layer deposition (ALD) is directed to proceed exclusively within a 3D trench structure, by covering the top of the trench with an amorphous carbon (aC) inhibition layer. The aC layer is applied selectively on the top surface of the trench by exploiting the ion-radical synergy required for its deposition. Since the aC layer lacks adsorption sites for ALD precursors, growth of the target material is inhibited on the top surface of the trench, whereas it occurs selectively within the trench. After several ALD cycles of selective deposition of the target material, the aC layer is removed and reapplied in a supercycle recipe until sufficient material has been deposited in the trench. The selective deposition of an aC inhibition layer on the top surface of the trench, as well as the selective deposition of 3.0 ± 0.1 nm of TiO₂ in a trench is demonstrated on a 3D nanostructure.