Buried digitline (BDL) access device and memory array

摘要

A memory array includes a plurality of digitline (DL) trenches extending along a first direction; a buried digitline between the DL trenches; a trench fill material layer sealing an air gap in each of the DL trenches; a plurality of wordline (WL) trenches extending along a second direction; an active chop (AC) trench disposed at one end of the buried digitline; a shield layer in the air gap; and a sidewall conductor around the sidewall of the AC trench.