Some embodiments include an integrated assembly having semiconductor material structures which each have a transistor channel region, and which are over metal-containing structures. Carbon-doped oxide is adjacent regions of each of the semiconductor material structures and sidewalls of the metal-containing structures. Some embodiments include an integrated assembly having pillars of semiconductor material. Each of the pillars has four sidewalls. Two of the four sidewalls of each pillar are gated sidewalls. The other two of the four sidewalls are non-gated sidewalls. Carbon-doped silicon dioxide is adjacent and directly against the non-gated sidewalls. Some embodiments include a method of forming an integrated assembly. Rails of semiconductor material are formed. A layer of carbon-doped silicon dioxide is formed adjacent top surfaces and sidewall surfaces of each of the rails. Trenches are formed which slice the semiconductor material of the rails into pillars. Wordlines are formed within the trenches and along the pillars.