Following the hot hydrogen pre-treatment the initial silicon deposition commences with the introduction of silane gas to the reactor. During this initial step, the current is reduced to 8 amps and the filament temperature is maintained at approximately 650 °F. Silane flow is started to replace the hydrogen and begin the decomposition. The rate and quantity of silane flow and the filament temperature are controlled based on the type of final silicon product that is desired. For FZ grade silicon, the treatment is designed to create a cohesive interface with the filament surface. This interface is less important with other products.