0.29-μm/sup 2/ trench cell technologies for 1G-bit DRAMs with open/folded-bit-line layout and selective growth technique

Abstract

We present substrate-plate-trench cell technologies for 1G-bit DRAMs. With an open/folded-bit-line layout, the smallest cell area of 0.29 /spl mu/m/sup 2/ was realized for a 0.20 /spl mu/m design rule. A pause time of 4.2 s at 85/spl deg/C and an activation energy of 0.70 eV were achieved for a 0.25-/spl mu/m/spl Phi//spl times/4-/spl mu/m trench capacitor. A new Si selective epitaxial growth (SEG) technique was developed to reduce connection formation between the capacitor and transistor to one fabrication step, and also reduce a distance between the trench and gate. The gate capacitors on the SEG showed a breakdown electric field over 11 MV/cm even when the distance was less than 0.1 /spl mu/m.