A wafer process chamber includes a wafer support in the wafer process chamber, the wafer support configured to support a wafer. The process chamber includes a gas diffuser unit within the wafer process chamber. The gas diffuser unit includes at least one controllable diffuser configured to generate one or more controllable forces acting in various directions on a gaseous material in a flow of the gaseous material introduced into the process chamber, to spread the gaseous material inside the process chamber. The gas diffuser unit includes a power source coupled to the at least one controllable diffuser, the power source configured to supply power to the at least one controllable diffuser to generate the one or more controllable forces. The gas diffuser unit includes a controller coupled to the power source, the controller configured to control the power supplied by the power source to the at least one controllable diffuser.