(Invited) Photo-Assisted ALD: Process Development and Application Perspectives

Atomic layer deposition (ALD) is a highly versatile thin-film deposition method that is presently utilized in many steps within microelectronic process flow and is gaining more and more interest in other fields of industry as well. The prosperity of ALD originates from its capability to controllably deposit high-quality films uniformly and conformally over large areas and complicated features. However, one of the main challenges of ALD, lateral control of film growth, stems from these same properties. Selective-area ALD (S-ALD) is presently a subject of intense research and development work as the targeted feature sizes in the semiconductor applications have reduced to a level exceeding the capabilities of lithography methods. Photo-assisted ALD (Photo-ALD) is a less-studied approach to facilitate S-ALD and selection of materials accessible with Photo-ALD is scarce. The present paper contributes to this field by reporting studies on Photo-ALD processes for metal oxides and metals.