Integrated Assemblies Having Rugged Material Fill, and Methods of Forming Integrated Assemblies

Some embodiments include a structure having an opening extending into an integrated configuration. A first material is within the opening, and is configured to create an undulating topography relative to a sidewall of the opening. The undulating topography has a surface roughness characterized by a mean roughness parameter Rmean which is the mean peak-to-valley distance along the undulating topography. The Rmean is at least about 4 nm. A second material is within the opening and along at least a portion of the undulating topography. The first and second materials are compositionally different from one another. Some embodiments include integrated assemblies. Some embodiments include methods of forming integrated assemblies.