The LPCVD system is a stack or cabinet that holds four horizontal tubes that each runs a separate process. Four tubes each is a large quartz tube that is sealed at the front with a door while the back of the tube is connected to a vacuum pump. Around each quartz tube is heating elements that heat the tube and it contents up to the correct temperature. With a vacuum in the tube and at the correct temperature, the gases are entered into teh tube. The heat causes the gases to react and a film is deposited. The amount of film is determined by the amount of time the gas step is ran into the tube.