Non-planar transistor devices which include oxide isolation structures formed in semiconductor bodies thereof through the formation of an oxidizing catalyst layer on the semiconductor bodies followed by an oxidation process. In one embodiment, the semiconductor bodies may be formed from silicon-containing materials and the oxidizing catalyst layer may comprise aluminum oxide, wherein oxidizing the semiconductor body to form an oxide isolation zone forms a semiconductor body first portion and a semiconductor body second portion with the isolation zone substantially electrically separating the semiconductor body first portion and the semiconductor body second portion.