The feasibility of Sn, In, or Al doped ZnSb thin film as candidates for phase change material

The potentials of Sn, In, or Al doped ZnSb thin film as candidates for phase change materials have been studied in this paper. It was found that the Zn-Sb bonds were broken by the addition of the dopants and homopolar Zn-Zn bonds and other heteropolar bonds, such as Sn-Sb, In-Sb, and Al-Sb, were subsequently formed. The existence of homopolar Sn-Sn and In-In bonds in Zn₅₀Sb₃₆Sn₁₄ and Zn₄₁Sb₃₆In₂₃ films, but no any Al-Al bonds in Zn₃₅Sb₃₀Al₃₅ film, was confirmed. All these three amorphous films crystallize with the appearance of crystalline rhombohedral Sb phase, and Zn₃₅Sb₃₅Al₃₅ film even exhibits a second crystallization process where the crystalline AlSb phase is separated out. The Zn₃₅Sb₃₀Al₃₅ film exhibits a reversible phase change behavior with a larger Ea ( 4.7 eV), higher Tc (~ 245ᴼ C), better 10-yr data retention (~ 182ᴼ C), less incubation time (20 ns at 70 mW), and faster complete crystallization speed (45 ns at 70 mW). Moreover, Zn₃₅Sb₃₀Al₃₅ film shows the smaller root-mean-square (1.654 nm) and less change of the thickness between amorphous and crystalline state (7.5%), which are in favor of improving the reliability of phase change memory.This work was financially supported by the Natural Science Foundation of China (Grant Nos. 61306147, 61377061), the Public Project of Zhejiang Province (Grant No.2014C31146), the Young Leaders of academic climbing project of the Education Department of Zhejiang Province (pd2013092), the Natural Science Foundation of Zhejiang Province (Grant No. LQ15F040002), the Scientific Research Foundation of Graduate School of Ningbo University, and sponsored by K. C. Wong Magna Fund in Ningbo University

Enhanced thermal stability and electrical behavior of Zn-doped Sb2Te films for phase change memory application

Zn-doped Sb₂Te films are proposed to present the feasibility for phase-change memory application. Zn atoms are found to significantly increase crystallization temperature of Zn x (Sb₂Te)1−x films and be almost linearly with the wide range of Zn-doping concentration from x = 0 to 29.67 at.%. Crystalline resistances are enhanced by Zn-doping, while keeping the large amorphous/crystalline resistance ratio almost constant at ∼10⁵. Especially, the Zn 26.07 (Sb₂Te)73.93 and Zn 29.67 (Sb₂Te)70.33 films exhibit a larger resistance change, faster crystallization speed, and better thermal stability due to the formation of amorphous Zn-Sb and Zn-Te phases as well as uniform distribution of Sb₂Te crystalline grains

Phase change behaviors of Zn-doped Ge2Sb2Te5 films

This work was financially supported by the Program for New Century Excellent Talents in University (Grant No. NCET-10-0976), the International Science & Technology Cooperation Program of China (Grant No. 2011DFA12040), the National Program on Key Basic Research Project (973 Program) (Grant No. 2012CB722703), the Natural Science Foundation of China (Grant Nos. 61008041 and 60978058), the Natural Science Foundation of Zhejiang Province, China (Grant No. Y1090996), the Natural Science Foundation of Ningbo City, China (Grant No. 2011A610092), the Program for Innovative Research Team of Ningbo city (Grant No. 2009B21007), and sponsored by K. C. Wong Magna Fund in Ningbo University

Improved phase-change characteristics of Zn-doped amorphous Sb₇Te₃ films for high-speed and low-power phase change memory

The superior performance of Zn-doped Sb₇Te₃ films might be favorable for the application in phase change memory. It was found that Zn dopants were able to suppress phase separation and form single stable Sb2Te crystal grain, diminish the grain size, and enhance the amorphous thermal stability of Sb₇Te₃ film. Especially, Zn 30.19(Sb₇Te₃)69.81 film has higher crystallization temperature (∼258 °C), larger crystallization activation energy (∼4.15 eV), better data retention (∼170.6 °C for 10 yr), wider band gap (∼0.73 eV), and higher crystalline resistance. The minimum times for crystallization of Zn 30.19(Sb₇Te₃)69.81 were revealed to be as short as ∼10 ns at a given proper laser power of 70 mW.This work was financially supported by the International Science & Technology Cooperation Program of China (Grant No. 2011DFA12040), the National Program on Key Basic Research Project (973 Program) (Grant No. 2012CB722703), the Natural Science Foundation of China (Grant Nos. 61008041 and 60978058), the CAS Special Grant for Postgraduate Research, Innovation and Practice, the Program for Innovative Research Team of Ningbo city (Grant No. 2009B21007), and sponsored by K. C. Wong Magna Fund in Ningbo University

Adjuvant therapy for T3N0 rectal cancer in the total mesorectal excision era- identification of the high risk patients

<p>Abstract</p> <p>Background</p> <p>Adjuvant therapy for T3N0 rectal cancer was controversial with respect to both radiation and the use of a combined regimen of chemotherapy. We evaluated both clinical features and biomarkers and sought to determine risk factors for those patients retrospectively.</p> <p>Methods</p> <p>A total of 122 patients with T3N0 rectal cancer were analyzed in this study from January 2000 to December 2005. Clinicopathologic and biomarkers were used to predict local recurrence (LR), disease-free survival (DFS), and overall survival (OS).</p> <p>Results</p> <p>The median follow-up interval was 45.4 months. Five-year LR, DFS, and OS rates were 10.4%, 68.3%, and 88.7%. Having a lower tumor location and showing low P21 and high CD44v6 expression were identified as risk factors for LR: patients with two or three of these risk factors had a higher 5-year LR rate (19.3%) than did patients with none or one of these risk factors (6.8%) (p = 0.05). A poorer DFS was related to low P21 nor high CD44v6 expression but not to tumor location: the 5-year DFS rates were 79.3% for those with neither, 65.9% for those with either one or the other, and 16.9% for those with both (p = 0.00).</p> <p>Conclusions</p> <p>The prognostic model including tumor location, P21 and CD44v6 expressions could help to distinguish these patients with high risk T3N0 patients and determine whether adjuvant therapy was beneficial.</p

Te-based chalcogenide films with high thermal stability for phase change memory

This study reports on the synthesis of tellurium-based chalcogenide films that have high thermal stability for phase change memory application. Several Te-based chalcogenide alloys of In-Bi-Te, Ag-Bi-Te, In-Sb-Te, Sn-Sb-Te, Zn-Ge-Te, and Ga-Ge-Te are reported. Their thermal, optical, and electrical properties are investigated. The results show that Bi-Te-based films have a higher crystallization temperature and greater activation energy compared with the other Sb-Te-based and Ge-Te-based films. Especially, In₂.₈Bi₃₆.₆Te₆₀.₆film exhibits high crystallization temperature (252 °C) and great activation energy (5.16 eV), showing much improved amorphous thermal stability. A relatively wider optical band gap (0.674 eV) of thermal annealed In₂.₈Bi₃₆.₆Te₆₀.₆film is obtained. In addition, it also has a higher amorphous/crystalline resistance ratio of about 10⁵, implying that current consumption could be low in the phase-change memory operation.This work was financially supported by the Natural Science Foundation of China (Grant Nos. 61008041, 61107047, and 60978058), the Natural Science Foundation of Zhejiang Province, China (Grant No. Y1090996), the Natural Science Foundation of Ningbo City, China (Grant No. 2011A610092), the Ningbo optoelectronic materials and devices creative team (Grant No. 2009B21007), the Open Research Fund of State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences (Grant No. SKLST201010), and sponsored by K. C. Wong Magna Fund in Ningbo University