Method of removing impurity metals from semiconductor devices
AssigneeBell Telephone Laboratories, Incorporated
InventorPaul F. Schmidt
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Abstract
A process is disclosed for gettering deleterious metal impurities, particularly the transition metals such as Cu, Fe, Co, Ni and Cr from silicon wafers by high temperature treatment for a comparatively short time in a hydrogen chloride vapor at low oxygen pressure. The low oxygen pressure inhibits the oxide growth on the silicon surfaces to thicknesses of not more than about 150 Angstroms, sufficient to protect the silicon surface but not so thick as to constitute a barrier to outdiffusion of the gettered impurities. This particular process may be preceded and followed by other previously known gettering techniques.
Claims8
In a process for gettering transition metal impurities from a body of silicon semiconductor material which comprises heating the body in an ambient which includes hydrogen chloride and oxygen
- the improvement comprising the ambient contains oxygen in a percentage by volume of from about 0.5 and 1.0 to grow a silicon oxide film on the surface of said body to a thickness of not more than about 150 Angstroms.
In a process for gettering transition metal impurities from a body of silicon semiconductor material which comprises heating the body in an ambient which includes hydrogen chloride and dry oxygen
- the improvement comprising the ambient comprises by volume, hydrogen chloride about 0.5 percent, oxygen from about 0.5 to 1.0 percent, and the balance argon.
Dependencies are inferred from the claim text.