PURPOSE: To produce an alkali metal diffusion preventing layer having high alkali metal diffusion preventing property by performing phosphorus ion implantation simultaneously or alternately with oxygen ion implantation and then applying heating treatment to a base material.
CONSTITUTION: Phosphorus ion implantation is applied to a silicon-containing base material to form an alkali metal diffusion preventing layer containing phosphorus in the inner part of the base material. At this time, phosphorus ion implantation is performed simultaneously or alternately with oxygen ion implantation and then the heating treatment of the base material is exerted, or, after phosphorus ion implantation, oxygen ion implantation is performed in a state where the base material is heated. Further, after the conclusion of phosphorus ion implantation, the heating treatment of the base material is carried out in an oxygen-containing atmosphere. By this method, the adverse effect of the alkali metal contained in a substrate for device can be prevented.
TAGAMI TAKASHI
TANAKA SHUHEI
| JPS6384123A | 1988-04-14 |
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