Wet thermal annealing effects on the properties of TaN/HfO2/Ge metal-oxide-semiconductor （MOS） structures with and without a GeO2 passivation layer are investigated. The physical and the electrical properties are ch...Wet thermal annealing effects on the properties of TaN/HfO2/Ge metal-oxide-semiconductor （MOS） structures with and without a GeO2 passivation layer are investigated. The physical and the electrical properties are characterized by X-ray photoemission spectroscopy, high-resolution transmission electron microscopy, capacitance-voltage （C-V） and current-voltage characteristics. It is demonstrated that wet thermal annealing at relatively higher temperature such as 550 ℃ can lead to Ge incorporation in HfO2 and the partial crystallization of HfO2, which should be responsible for the serious degradation of the electrical characteristics of the TaN/HfO2/Ge MOS capacitors. However, wet thermal annealing at 400 ℃ can decrease the GeOx interlayer thickness at the HfO2/Ge interface, resulting in a significant reduction of the interface states and a smaller effective oxide thickness, along with the introduction of a positive charge in the dielectrics due to the hydrolyzable property of GeOx in the wet ambient. The pre-growth of a thin GeO2 passivation layer can effectively suppress the interface states and improve the C V characteristics for the as-prepared HfO2 gated Ge MOS capacitors, but it also dissembles the benefits of wet thermal annealing to a certain extent.展开更多
研究了NixCo1–x(OH)2干凝胶中钴含量对其电性能及循环稳定性的影响。用溶胶-凝胶法制备了NixCo1–x(OH)2干凝胶材料,用液氮吸附、XPS和XRD研究了含钴Ni(OH)2干凝胶的组成和结构,用恒电流技术研究了它们的电容性能。结果表明,NixCo1–x(...研究了NixCo1–x(OH)2干凝胶中钴含量对其电性能及循环稳定性的影响。用溶胶-凝胶法制备了NixCo1–x(OH)2干凝胶材料,用液氮吸附、XPS和XRD研究了含钴Ni(OH)2干凝胶的组成和结构,用恒电流技术研究了它们的电容性能。结果表明,NixCo1–x(OH)2干凝胶具有较高的比表面积和丰富的中孔;添加钴改善了NixCo1–x(OH)2干凝胶的倍率性能,当钴含量达到24%时效果最佳;充放电后CoxNi1–x(OH)2干凝胶的晶态结构仍是β-Ni(OH)2晶相结构,钴含量20%以上的CoxNi1–x(OH)2干凝胶充放电后微晶尺寸变化不明显;组成的活性炭/Ni0.76Co0.24(OH)2干凝胶电容器20 m A/cm2充放电循环时,库仑效率达到95%以上,循环100000次以上,电容器的比容量仍保持在90%以上。在长循环过程中,Ni0.76Co0.24(OH)2干凝胶的微晶尺寸变化不大,微晶晶胞a轴逐渐变大、c轴逐渐缩小,晶胞参数趋向理想的β-Ni(OH)2晶体。展开更多
High dielectric constant can be reached in a reductive-sintered Sr_(1-x)Ba_(x)TiO_(3)barrier-layer capacitor with core‒rim structures as dominant microstructural features.By SEM and aberration-corrected TEM observatio...High dielectric constant can be reached in a reductive-sintered Sr_(1-x)Ba_(x)TiO_(3)barrier-layer capacitor with core‒rim structures as dominant microstructural features.By SEM and aberration-corrected TEM observations,an interfacial zone between the core and rim,named as white-rim(w-rim),was found always enriched with Ba,while the core was free of Ba solution.The reductive liquid-phase sintering resulted in three times the concentrations of oxygen vacancies(VO)into cores and rims compared to their A-site vacancies(VA),while enabling the highest concentration of VO(~17%)without VA in w-rim.The strained core/w-rim interfaces,with obvious interfacial polarizations,which can effectively raise the dielectric constant,were expected to be created from a temporary equilibrium between the cores and the liquidphase.The synergetic evolution of core‒rim structures,SreO vacancies,multiple internal polarized structures can be utilized to better control and optimize dielectric behaviors and other functionalities for perovskite capacitors and other multi-functional ceramics.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61176092,61036003,and 60837001)the National Basic Research Program of China (Grant No. 2012CB933503)+1 种基金the Ph.D. Program Foundation of Ministry of Education of China (Grant No. 20110121110025)the Fundamental Research Funds for the Central Universities,China (Grant No. 2010121056)
文摘Wet thermal annealing effects on the properties of TaN/HfO2/Ge metal-oxide-semiconductor （MOS） structures with and without a GeO2 passivation layer are investigated. The physical and the electrical properties are characterized by X-ray photoemission spectroscopy, high-resolution transmission electron microscopy, capacitance-voltage （C-V） and current-voltage characteristics. It is demonstrated that wet thermal annealing at relatively higher temperature such as 550 ℃ can lead to Ge incorporation in HfO2 and the partial crystallization of HfO2, which should be responsible for the serious degradation of the electrical characteristics of the TaN/HfO2/Ge MOS capacitors. However, wet thermal annealing at 400 ℃ can decrease the GeOx interlayer thickness at the HfO2/Ge interface, resulting in a significant reduction of the interface states and a smaller effective oxide thickness, along with the introduction of a positive charge in the dielectrics due to the hydrolyzable property of GeOx in the wet ambient. The pre-growth of a thin GeO2 passivation layer can effectively suppress the interface states and improve the C V characteristics for the as-prepared HfO2 gated Ge MOS capacitors, but it also dissembles the benefits of wet thermal annealing to a certain extent.
文摘研究了NixCo1–x(OH)2干凝胶中钴含量对其电性能及循环稳定性的影响。用溶胶-凝胶法制备了NixCo1–x(OH)2干凝胶材料,用液氮吸附、XPS和XRD研究了含钴Ni(OH)2干凝胶的组成和结构,用恒电流技术研究了它们的电容性能。结果表明,NixCo1–x(OH)2干凝胶具有较高的比表面积和丰富的中孔;添加钴改善了NixCo1–x(OH)2干凝胶的倍率性能,当钴含量达到24%时效果最佳;充放电后CoxNi1–x(OH)2干凝胶的晶态结构仍是β-Ni(OH)2晶相结构,钴含量20%以上的CoxNi1–x(OH)2干凝胶充放电后微晶尺寸变化不明显;组成的活性炭/Ni0.76Co0.24(OH)2干凝胶电容器20 m A/cm2充放电循环时,库仑效率达到95%以上,循环100000次以上,电容器的比容量仍保持在90%以上。在长循环过程中,Ni0.76Co0.24(OH)2干凝胶的微晶尺寸变化不大,微晶晶胞a轴逐渐变大、c轴逐渐缩小,晶胞参数趋向理想的β-Ni(OH)2晶体。
基金supported by the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20240969)the National Natural Science Foundation of China(Grants No.51532006 and No.51702168)+3 种基金Shanghai Technical Service Center for Advanced Ceramics Structure Design and Precision Manufacturing(NO.20DZ2294000)the support from Beijing Municipal Natural Science Foundation(Grant No.1212016)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB36000000)the CAS Pioneer Hundred Talents Program.
文摘High dielectric constant can be reached in a reductive-sintered Sr_(1-x)Ba_(x)TiO_(3)barrier-layer capacitor with core‒rim structures as dominant microstructural features.By SEM and aberration-corrected TEM observations,an interfacial zone between the core and rim,named as white-rim(w-rim),was found always enriched with Ba,while the core was free of Ba solution.The reductive liquid-phase sintering resulted in three times the concentrations of oxygen vacancies(VO)into cores and rims compared to their A-site vacancies(VA),while enabling the highest concentration of VO(~17%)without VA in w-rim.The strained core/w-rim interfaces,with obvious interfacial polarizations,which can effectively raise the dielectric constant,were expected to be created from a temporary equilibrium between the cores and the liquidphase.The synergetic evolution of core‒rim structures,SreO vacancies,multiple internal polarized structures can be utilized to better control and optimize dielectric behaviors and other functionalities for perovskite capacitors and other multi-functional ceramics.
