Nitrogen-implanted Ge_2Sb_2Te_5 film used as multilevel storage media for phase change random access memory

摘要

Ge_2Sb_2Te_5 films were deposited by RF magnetron sputtering on Si(100)/SiO_2 substrates. N~+ ion was implanted into Ge_2Sb_2Te_5 films. Two obvious steps were observed in the resistance-temperature curve of the Ge_2Sb_2Te_5-N film with a minor nitrogen implant dose. The two steps may change into one step because the phase transition from FCC to hexagonal structure was suppressed by nitrogen implantation if the nitrogen implant dose is higher than 4.51 x 10~(16) cm~(-2). The favourite nitrogen implant dose is about 6.44 x 10~(15) to 1.92 x 10~(16) cm~(-2) in our study. This phenomenon is very important for multilevel storage. Three-level storage with Ge_2Sb_2Te_5-N media for chalcogenide random access memory (C-RAM) can be performed easily, and hence, the capacity of C-RAM will be dramatically increased.