3D MEMORY WITH VERTICAL BIT LINES AND STAIRCASE WORD LINES AND VERTICAL SWITCHES AND METHODS THEREOF

摘要

A 3D memory with vertical local bit lines global bit lines has an in-line vertical switch in the form of a thin film transistor (TFT) formed as a vertical structure, to switch a local bit line to a global bit line. The TFT is implemented to switch a maximum of current carried by the local bit line by a strongly coupled select gate which must be fitted within the space around the local bit line. Maximum thickness of the select gate is implemented with the select gate exclusively occupying the space along the x-direction from both sides of the local bit line. The switches for odd and even bit lines of the row are staggered and offset in the z-direction so that the select gates of even and odd local bit lines are not coincident along the x-direction. The switching is further enhanced with a wrap-around select gate.