Pitcher-shaped active area for field effect transistor and method of forming same

A method of forming a pitcher-shaped active area structure for a field effect transistor (FET), the method comprising:

• implementing an etch to remove a pad oxide layer formed on a substrate and portions of an STI oxide fill and STI liner oxide that form top portions of sidewalls of at least two shallow trench insulator (STI) structures that isolate a FET and define an active area structure, thereby forming divots in the top portions of the sidewalls of the at least two STI structures, wherein the etch is selected from the group consisting of a wet etch and a plasma etch, wherein the STI structures comprise insulation, wherein the divots define recesses below a top surface of the substrate and below a top surface of the insulation, and wherein the recesses have boundaries formed by the top portions of the side walls and by exterior surfaces of the insulation;
• and
• implementing a hydrogen annealing technique to migrate substrate material into at least portions of the divots, thereby forming a widened top portion of the active area structure with a larger width than a bottom portion of the active area structure.