Selective Growth of Titanium Nitride on HfO2 across Nanolines and Nanopillars

This work targets the area selective atomic layer deposition (AS-ALD) of TiN onto HfO2 for use as the word line in a memory device. Unlike other patterning processes, AS-ALD eliminates etching steps and also allows for growth of patterned films with precise thickness control. This study investigates how AS-ALD differs on planar and nonplanar surfaces. Using a combination of X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy, we demonstrate a way to confer selectivity to a substrate using surface features. Self-assembled monolayers form defects at regions of high curvature, allowing nucleation of TiN films in ALD. This is in contrast to a treated planar surface with no features, which exhibits complete blocking of TiN up to a certain limit of ALD cycles.