Methods and compositions for the selective etching of silicon
AssigneeInternational Business Machines Corporation
InventorsLarry W. Austin, Harold G. Linde, James S. Nakos
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Abstract
Methods and compositions for the selective etching of silicon in the presence of p-doped silicon are disclosed whereby a portion of a silicon surface may be dissolved while a p-doped pattern in the surface remains substantially undissolved. The compositions comprise (a) an aqueous solution of an alkali metal hydroxide or a tetraalkylammonium hydroxide; and (b) a high flash point alcohol, phenol, polymeric alcohol, or polymeric phenol.
Claims7
A method for the controlled etching of a silicon substrate comprising exposing said silicon substrate to a mixture of (a) an aqueous solution of a base chosen from the group consisting of alkali metal hydroxides and tetraalkylammonium hydroxides and (b) an alcohol of structure ##STR5## wherein Ar is aryl or substituted aryl;
- R' is hydrogen or linear lower alkyl;
- n is zero or an integer from 1 to 4;
- and
- m is zero or one.
A method for fabricating a p-doped structure on a surface of a silicon wafer comprising:
- (a) patterning said surface of said wafer with a pattern containing at least 2.times.10.sup.19 atoms/cm.sup.3 of p-dopant;
- and
- (b) exposing said surface to a solution of an alcohol and an aqueous base, said alcohol having the formula ##STR6## wherein Ar is aryl or aryl substituted with lower alkyl or halogen;
- R' is hydrogen or linear lower alkyl;
- n is zero or an integer from 1 to 4;
- and
- m is zero or one;
- and said base is chosen from the group consisting of alkali metal hydroxides and tetraalkylammonium hydroxides, whereby a portion of said silicon surface of said wafer is dissolved at a rate at least 6 times that of said pattern.
Dependencies are inferred from the claim text.