New Erase Constraint for the Junction-Less Charge-Trap Memory Array in Cylindrical Geometry

This paper presents a detailed simulation analysis of the erase performance of junction-less charge-trap memory arrays in the cylindrical geometry, showing that a saturation of the erased threshold voltage occurs as a result of incomplete inversion of the intercell regions when positive charge is stored in the cells. This erase saturation issue is investigated as a function of string and cell parameters, revealing lower erase capabilities for large cell-to-cell separation, small substrate radius, and small equivalent-oxide thickness of the gate stack. These results add new constraints to the design of cylindrical junction-less memory technologies.