Wacker Chemie Ag

Friedrich Popp

Harald Hertlein

Tobias Weiss

Christian Kutza

Martin Roeckl

The rate of rod fallover in the production of polycrystalline silicon by the Siemens process is sharply reduced by cleaning the Siemens reactor base plate by at least a two-step procedure comprising suctioning the base plate in one step, and subsequently cleaning with liquid or solid cleaning medium in a second step, between each phase of rod removal and new support body installation.

Method for producing polycrystalline silicon

A gas distribution system for a polysilicon deposition reactor eliminates or mitigates the problems associated with prior art distribution systems employs at least two segments which are gas-tightly connected to one another by readily detachable fasteners, with at least one gas inlet opening and one gas outlet opening, the gas distributor of the system being mounted by readily detachable fasteners to the polysilicon reactor.

Gas distributor for a Siemens reactor

The native oxide layer on silicon support rods in the Siemens polysilicon production process is removed by heating the rods to a temperature of 1100-1200&#xb0; C. and contacting the rods with hydrogen at a system pressure of 1.1E5 to 6E6 Pa. Oxide is rapidly removed, reducing overall process time and increasing space time yield. The use of hydrogen, optionally purified from a polysilicon deposition and containing only traces of HCl reduces reactor corrosion and loss of silicon from the support rods.

Contamination of surfaces of polysilicon rods removed from a Siemens reactor in a polysilicon production facility is reduced by cleaning the production facility at least every other week with a cleaning liquid containing water, optionally also containing neutral surfactants.

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Ooltewah, TN, United States of America

Friedrich Popp