A substrate processing system has a housing that defines a process chamber, a gas-delivery system, a high-density plasma generating system, a substrate holder, and a controller. The housing includes a sidewall and a dome positioned above the sidewall. The dome has physically separated and noncontiguous pieces. The gas-delivery system introduces e a gas into the process chamber through side nozzles positioned between two of the physically separated and noncontiguous pieces of the dome. The high-density plasma generating system is operatively coupled with the process chamber. The substrate holder is disposed within the process chamber and supports a substrate during substrate processing. The controller controls the gas-delivery system and the high-density plasma generating system.