Selective self-aligned patterning of silicon germanium, germanium and type iii/v materials using a sulfur-containing mask

A method for patterning a substrate including multiple layers using a sulfur-based mask, comprising:

• a) providing a substrate including a first layer and a second layer arranged on the first layer, the first layer including a material selected from a group consisting of germanium, silicon germanium and type III/V materials, the second layer including the material and one or more other materials, and the material is greater than or equal to 50% by weight of the second layer;
• b) cleaning the substrate;
• c) enhancing a surface of the substrate to increase bonding of a mask layer;
• d) depositing the mask layer including a sulfur species onto sidewalls of the first layer and the second layer by exposing the substrate to a first wet chemistry;
• e) removing the mask layer on the sidewalls of the second layer while not completely removing the mask layer on the sidewalls of the first layer by exposing the substrate to a second wet chemistry;
• f) selectively etching the second layer relative to the first layer by exposing the substrate to a third wet chemistry;
• and
• g) repeating d), e) and f) one or more times.