Processes for enhancing solubility and the reaction rates in supercritical fluids are provided. In preferred embodiments, such processes provide for the uniform and precise deposition of metal-containing films on semiconductor substrates as well as the uniform and precise removal of materials from such substrates. In one embodiment, the process includes, providing a supercritical fluid containing at least one reactant, the supercritical fluid being maintained at above its critical point, exposing at least a portion of the surface of the semiconductor substrate to the supercritical fluid, applying acoustic energy, and reacting the at least one reactant to cause a change in at least a portion of the surface of the semiconductor substrate.