A system and a method for forming semiconductor features

An inductively coupled power (ICP) plasma processing chamber for forming semiconductor features is provided. A plasma processing chamber is provided, comprising a vacuum chamber, at least one antenna adjacent to the vacuum chamber for providing inductively coupled power in the vacuum chamber, a substrate support for supporting a silicon substrate within the plasma processing chamber, a pressure regulator, a gas inlet for providing gas into the plasma processing chamber, and a gas outlet for exhausting gas from the plasma processing chamber. A gas distribution system is in fluid connection with the gas inlet for providing a first gas and a second gas, wherein the gas distribution system can substantially replace one of the first gas and the second gas in the plasma zone with the other of the first gas and the second gas within a period of less than 5 seconds.