At&t Technologies, Inc.

American Telephone and Telegraph, Co.

American Telephone and Telegraph Company, At&t Technologies, Inc.

Daniel D Leffel

William Graham Easter

Donald M Large

Richard K Beltz

A method has been developed for altering the resistivity of selected regions (tubs) in a dielectrically isolated (DI) wafer. Subsequent to the formation of the conventional tub structure, the wafer is patterned and etched to expose selected tubs. These tubs are then etched and selectively implanted and an epitaxial layer of a new resistivity value is grown in the empty tube regions. The resistivity of the epitaxial material may be chosen to alter the conductivity of the selected tub regions.

Method of forming complementary device structures in partially processed

A method has been developed for providing tub regions with various resistivities in a dielectrically isolated (DI) structure. The starting substrate material is etched to expose the locations designated for a resistivity modification, and epitaxial material of the modified resistivity value is used to fill the exposed tubs. The remainder of the fabrication process follows conventional DI fabrication techniques. The procedure may simply be used to create a DI structure containing both n-type and p-type tube regions. The idea may also be extended, however, to providing separate tubs with, for example, n+ resistivity, n- resistivity, p- resistivity and p+ resistivity, all within the same DI structure.

Technique for fabricating complementary dielectrically isolated wafer

Wafers (12), including those in the solid state electronics industry, are demounted from an adherent surface (79). A respective passageway (90) is extended from a fluid supply device (92), through the adherent surface (79) to and in communication with, the mounting surface (16) of a respective wafer (12). The fluid is applied via the passageway (90) to and between the mounting surface (16) of the wafer (12) and the adherent surface (79) with sufficient pressure to dislodge the wafer (12). In an advantageous embodiment, the passageway (90) extends to a location between about the centerline (98) and the periphery of the wafer (12). The fluid is thereby applied in an off-center manner with leveraged force to break the seal between the adherent surface (79) and the wafer (12).

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Earl Township, Berks County, PA, United States of America

Daniel D Leffel