Patents by Inventor Jen-shen Maa

Jen-shen Maa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4609447
    Abstract: A method of determining the presence of alkali metal ions in a substrate comprising silicon or silicon doped with a p-type conductivity modifier is provided. The substrate to be tested is etched in a tetrafluoromethane/oxygen plasma and the etch rate is compared against that of similar substrates containing known concentrations of alkali metal ions. The etch rate will increase with increasing alkali metal concentration. The subject method is particularly useful in determining the level of alkali metal ion contamination during multistep processing of the above-named substrates.
    Type: Grant
    Filed: January 22, 1985
    Date of Patent: September 2, 1986
    Assignee: RCA Corporation
    Inventors: Lawrence K. White, Jen-shen Maa