In one embodiment, a method of fabricating one or more transistors in an integrated circuit includes an annealing step prior to a gate oxidation step. The annealing step may comprise a rapid thermal annealing (RTA) step performed prior to a gate oxidation pre-clean step. Among other advantages, the annealing step reduces a step height difference between P-doped and N-doped regions of a field oxide of a shallow trench isolation structure. The shallow trench isolation structure may be separating a PMOS transistor and an NMOS transistor in the integrated circuit.