Methods and systems for filling a gap

A method of filling a gap, the method comprising

• providing a substrate to a reaction chamber, the substrate comprising the gap, the substrate further comprising a proximal surface, the gap comprising a distal end and a sidewall;
• executing a plurality of super cycles, a super cycle comprising:
• a deposition cycle comprising a precursor pulse and a halogen reactant pulse;
• and
• a step of exposing the substrate to a transformation treatment;
• the precursor pulse comprising exposing the substrate to a precursor, the precursor comprising a compound having the general formula MLn, wherein M is a metal, wherein L is an aromatic ligand, and wherein n is an integer from at least 1 to at most 6;
• the halogen reactant pulse comprising exposing the substrate to a halogen reactant, the halogen reactant comprising a halogen;
• thereby at least partially filling the gap by preferentially forming a metal-containing material on the distal end compared to the proximal surface and the sidewall.