The SC increase is an effect of a lower GPC at the trench openings. We do not see a longer deposition depth in LHAR structures with Kr addition. We suggest that the added Kr acts to promote the diffusion of the NH3 into the trenches and to enhance surface desorption, primarily at the trench openings. More studies are needed to fully understand the effect of the added inert heavy gas. We foresee that this approach to superconformal ALD is applicable to many ALD processes.