Zone purification of silicon in a reactive plasma
AssigneeElectricite de France (Service National)
InventorsJacques Amouroux, Daniel Morvan
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Abstract
Boron is removed from silicon by zone melting purification. A jet of hot plasma obtained by high frequency excitation is directed on a zone of a bar of silicon to be purified. The plasma is formed from a mixture of a plasma-producing gas, such as argon, and an amount of oxygen which is sufficiently low to avoid oxidization of silicon.
Claims7
A process for zone melting purification of silicon, comprising the steps of melting a zone of a bar of silicon to be purified by directing a jet of hot plasma obtained by high frequency excitation onto said zone and moving the jet and bar with respect to each other so as to cause the melted zone to travel along the bar, wherein the plasma is formed from a mixture of a plasma-producing gas and a sufficiently small amount of oxygen to avoid substantial oxidation of silicon.
Dependencies are inferred from the claim text.