Patents by Inventor Thomas C. Chandler, Jr.

Thomas C. Chandler, Jr. 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).

  • Process for etching N, P, N+ and P+ type slugs and wafers
    Patent number: 5843322
    Abstract: A process for etching single crystal silicon semiconductor material of the N, P, N+ and P+ type slugs and wafers to delineate slip, lineage, dislocation, S-pit, twins, swirl and oxidation induced stacking fault defects involves the steps of:a) preparing a substantially metal-free etchant bath comprising nitric acid (70%), hydrofluoric acid (49%) and between approximately 35% to 98% by weight of glacial acetic acid (HAc) as a diluent, the minimum useful concentration of nitric acid being% Nitric acid.sub.min. =16.67?1-(% HAc/100)! and the maximum useful concentration of nitric acid being% Nitric acid.sub.max. =66.67?1-(% HAc/100)!, the minimum useful concentration of hydrofluoric acid being% HF.sub.min. =100%-% HAc % HNO.sub.3 max. and the maximum useful concentration of hydrofluoric acid being% HF.sub.max. -100%-% HAc-HNO.sub.2min.b) activating the etchant bath by generating NO.sub.x therein and allowing the temperature of the bath to rise to approximately 25.degree. to 34.degree. C.
    Type: Grant
    Filed: December 23, 1996
    Date of Patent: December 1, 1998
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: Thomas C. Chandler, Jr.