Method of preparing a high-purity polycrystalline silicon using a microwave heating system in a fluidized bed reactor

A method for preparing polycrystalline silicon comprising:

• supplying silicon seed to a single-column fluidized bed reactor to form a bed of silicon seed particles;
• introducing and dispersing a silicon-containing reacting gas into the reactor through a gas distribution means arranged below said bed to fluidize the silicon seed;
• heating the silicon seed above said gas distribution means by introducing microwave energy from at least one side of the reactor into a lower reaction zone of the reactor to deposit silicon from the silicon-containing reacting gas onto the silicon seed to form polycrystalline particles;
• introducing a coolant fluid into said gas distribution means;
• and
• cooling said gas distribution means with said coolant fluid to maintain said gas distribution means at a temperature to prevent substantial deposition of silicon on said gas distribution means.