The γ/γ＇ microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and scanning tra...The γ/γ＇ microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and scanning transmission electron microscopy （STEM）.The crystals were grown by the floating zone （FZ） method.Both cuboidal and spherical γ＇ precipitates were formed after a two-step aging.The size of the cuboidal γ＇ phases first increased and then decreased with the extension of the second-step aging time.Re,Co and Cr strongly concentrated in the γ phase whereas Ni and Al enriched in the γ＇ phase.Thermodynamic calculation by JMatPro was performed to explain the experimental observations.展开更多
Further improvement of storage density is a key challenge for the application of phase-change memory(PCM)in storage-class memory.However,for PCM,storage density improvements include feature size scaling down and multi...Further improvement of storage density is a key challenge for the application of phase-change memory(PCM)in storage-class memory.However,for PCM,storage density improvements include feature size scaling down and multilevel cell(MLC)operation,potentially causing thermal crosstalk issues and phase separation issues,respectively.To address these challenges,we propose a high-aspect-ratio(25:1)lateral nanowire(NW)PCM device with conventional chalcogenide Ge_(2)Sb_(2)Te_(5)(GST-225)to realize stable MLC operations,i.e.,low intra-and inter-cell variability and low resistance drift(coefficient=0.009).The improved MLC performance is attributed to the high aspect ratio,which enables precise control of the amorphous region because of sidewall confinement,as confirmed by transmission electron microscopy analysis.In summary,the NW devices provide guidance for the design of future high-aspect-ratio threedimensional PCM devices with MLC capability.展开更多
基金Project(08dj1400402) supported by the Major Program for the Fundamental Research of Science and Technology Committee of the Shanghai Municipality,ChinaProject(09ZZ16) supported by Innovation Program of Shanghai Municipal Education Committee,China
文摘The γ/γ＇ microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and scanning transmission electron microscopy （STEM）.The crystals were grown by the floating zone （FZ） method.Both cuboidal and spherical γ＇ precipitates were formed after a two-step aging.The size of the cuboidal γ＇ phases first increased and then decreased with the extension of the second-step aging time.Re,Co and Cr strongly concentrated in the γ phase whereas Ni and Al enriched in the γ＇ phase.Thermodynamic calculation by JMatPro was performed to explain the experimental observations.
基金supported by the National Natural Science Foundation of China(62174065)the Key Research and Development Plan of Hubei Province(2020BAB007)+1 种基金Hubei Provincial Natural Science Foundation(2021CFA038)the support from Hubei Key Laboratory of Advanced Memories&Hubei Engineering Research Center on Microelectronics。
文摘Further improvement of storage density is a key challenge for the application of phase-change memory(PCM)in storage-class memory.However,for PCM,storage density improvements include feature size scaling down and multilevel cell(MLC)operation,potentially causing thermal crosstalk issues and phase separation issues,respectively.To address these challenges,we propose a high-aspect-ratio(25:1)lateral nanowire(NW)PCM device with conventional chalcogenide Ge_(2)Sb_(2)Te_(5)(GST-225)to realize stable MLC operations,i.e.,low intra-and inter-cell variability and low resistance drift(coefficient=0.009).The improved MLC performance is attributed to the high aspect ratio,which enables precise control of the amorphous region because of sidewall confinement,as confirmed by transmission electron microscopy analysis.In summary,the NW devices provide guidance for the design of future high-aspect-ratio threedimensional PCM devices with MLC capability.
