A nano-scale-sized 3D element for phase change memories

摘要

A nano-scale-sized 3D phase change memory element has been successfully fabricated using novel metal sidewall pattern technology, based entirely on a CMOS process which is independent of lithographic size limitations. With Ge_2Sb_2Te_5 (GST) as the phase change material, a 280 nm x 35 nm contact area cell (equal to 100 nm contact diameter) has been successfully fabricated by 5 μm university lithographic techniques. The effects of annealing temperature on the GST resistivity and crystal structure have been studied. Static mode switching (dc tests) and pulse mode tests were performed, and an on/off ratio greater than 100 has been achieved.