Dichlorosilane compensating control strategy for improved polycrystalline silicon growth

A method comprising:

• providing a plurality of reactors each having a deposition chamber for deposition of polycrystalline silicon on a substrate;
• combining effluent from the plurality of reactors and processing the effluent to form a recycle stream comprising dichlorosilane and trichlorosilane wherein a fraction of the dichlorosilane in the recycle stream varies;
• blending a portion of the recycle stream with additional trichlorosilane to form a chlorosilane feed comprising chlorosilanes wherein the chlorosilanes in the feed are dichlorosilane and trichlorosilane and a fraction of the dichlorosilane in the chlorosilane feed varies;
• blending an amount of the chlorosilane feed with an amount of hydrogen to form a feed composition having a mol % of the chlorosilanes in hydrogen
• introducing the feed composition to the deposition chamber of one or more of the plurality of reactors at a total flow for each reactor;
• measuring the amount of dichlorosilane present in the chlorosilane feed and determining for each of the one or more of the plurality of reactors an offset value from a target value of dichlorosilane present in the chlorosilane feed for said each of the one or more of the plurality of reactors;
• adjusting the chlorosilane feed mole percent of the total flow into the deposition chamber of each of the one or more of the plurality of reactors by an amount inversely proportional to the dichlorosilane offset value for said each of the one or more of the plurality of reactors;
• and
• depositing polycrystalline silicon onto the substrates in each of said one or more of the plurality of reactors.