The breakthrough in data retention time of DRAM using Recess-Channel-Array Transistor(RCAT) for 88 nm feature size and beyond

Abstract

For the first time, 512 Mb DRAMs using a Recess-Channel-Array-Transistor(RCAT) are successfully developed with 88 nm feature size, which is the smallest feature size ever reported in DRAM technology with non-planar array transistor. The RCAT with gate length of 75 nm and recessed channel depth of 150 nm exhibits drastically improved electrical characteristics such as DIBL, BV/sub DS/, junction leakage and cell contact resistance, comparing to a conventional planar array transistor of the same gate length. The most powerful effect using the RCAT in DRAMs is a great improvement of data retention time. In addition, this technology will easily extend to sub-70 nm node by simply increasing recessed channel depth and keeping the same doping concentration of the substrate.