Methods of forming oxides, methods of forming semiconductor constructions, and methods of forming isolation regions

Some embodiments include methods of forming isolation regions in which spin-on material (for example, polysilazane) is converted to a silicon dioxide-containing composition. The conversion may utilize one or more oxygen-containing species (such as ozone) and a temperature of less than or equal to 300° C. In some embodiments, the spin-on material is formed within an opening in a semiconductor material to form a trenched isolation region. Other dielectric materials may be formed within the opening in addition to the silicon dioxide-containing composition formed from the spin-on material. Such other dielectric materials may include silicon dioxide formed by chemical vapor deposition and/or silicon dioxide formed by high-density plasma chemical vapor deposition.