Phase change memory （PCM） cell array is fabricated by a standard complementary metal-oxide-semiconductor process and the subsequent special fabrication technique. A chalcogenide Ge2Sb2Te5 film in thickness 50hm depo...Phase change memory （PCM） cell array is fabricated by a standard complementary metal-oxide-semiconductor process and the subsequent special fabrication technique. A chalcogenide Ge2Sb2Te5 film in thickness 50hm deposited by rf magnetron sputtering is used as storage medium for the PCM cell. Large snap-back effect is observed in current-voltage characteristics, indicating the phase transition from an amorphous state （higher resistance state） to the crystalline state （lower resistance state）. The resistance of amorphous state is two orders of magnitude larger than that of the crystalline state from the resistance measurement, and the threshold current needed for phase transition of our fabricated PCM cell array is very low （only several μA）. An x-ray total dose radiation test is carried out on the PCM cell array and the results show that this kind of PCM cell has excellent total dose radiation tolerance with total dose up to 2 ×10^6 rad（Si）, which makes it attractive for space-based applications.展开更多
The properties of the low-lying states especially the relevant shape coexistence in 80Ge, close to one of most neutron-rich doubly magic nuclei at N 50 and Z = 28, have been investigated within the framework of the pr...The properties of the low-lying states especially the relevant shape coexistence in 80Ge, close to one of most neutron-rich doubly magic nuclei at N 50 and Z = 28, have been investigated within the framework of the proton-neutron interacting model （IBM-2）. Based on the fact that the relative energy of the d neutron boson is different from that of the proton boson, the calculated energy levels of low-lying states and E2 transition strengths can reproduce the experimental data very well. Particularly, the first excited state 0＋, which is intimately related to the shape coexistence phenomenon, is reproduced quite nicely. The p2（E0,02＋→01＋） transition strength is also predicted. The experimental data and theoretical results indicate that both collective spherical and γ-soft vibration structures coexist in 80Ge.展开更多
基金Supported by the Chinese Academy of Sciences （Y2005027）, the Science and Technology Council of Shanghai （AM0517, 0452nm012, 04DZ05612, 04ZR14154, 04JC14080, 05JC14076, AM0414, 05nm05043）, the China Postdoctoral Science Foundation, and the K. C. Wong Education Foundation （Hong Kong）.
文摘Phase change memory （PCM） cell array is fabricated by a standard complementary metal-oxide-semiconductor process and the subsequent special fabrication technique. A chalcogenide Ge2Sb2Te5 film in thickness 50hm deposited by rf magnetron sputtering is used as storage medium for the PCM cell. Large snap-back effect is observed in current-voltage characteristics, indicating the phase transition from an amorphous state （higher resistance state） to the crystalline state （lower resistance state）. The resistance of amorphous state is two orders of magnitude larger than that of the crystalline state from the resistance measurement, and the threshold current needed for phase transition of our fabricated PCM cell array is very low （only several μA）. An x-ray total dose radiation test is carried out on the PCM cell array and the results show that this kind of PCM cell has excellent total dose radiation tolerance with total dose up to 2 ×10^6 rad（Si）, which makes it attractive for space-based applications.
基金Supported by National Natural Science Foundation of China(11475062,11647306,11147148)
文摘The properties of the low-lying states especially the relevant shape coexistence in 80Ge, close to one of most neutron-rich doubly magic nuclei at N 50 and Z = 28, have been investigated within the framework of the proton-neutron interacting model （IBM-2）. Based on the fact that the relative energy of the d neutron boson is different from that of the proton boson, the calculated energy levels of low-lying states and E2 transition strengths can reproduce the experimental data very well. Particularly, the first excited state 0＋, which is intimately related to the shape coexistence phenomenon, is reproduced quite nicely. The p2（E0,02＋→01＋） transition strength is also predicted. The experimental data and theoretical results indicate that both collective spherical and γ-soft vibration structures coexist in 80Ge.
