The Daniels’ barium vacancy layer model of semiconducting BaTiO3 ceramics is analyzed.A grain boundary barrier model with both acceptor states of grain boundary and barium vacancy diffusion layers for the transition ...The Daniels’ barium vacancy layer model of semiconducting BaTiO3 ceramics is analyzed.A grain boundary barrier model with both acceptor states of grain boundary and barium vacancy diffusion layers for the transition from PTC effect to grain boundary barrier layer (GBBL) capacitor is proposed.The proposed model solves the problem occurring in Daniels’ model and makes it possible to calculate physical properties of semiconducting BaTiO3 ceramics and relevant devices.展开更多
An ultrathin SrTiO3 dielectric layer is optimized through Al doping to solve the problems existing in development of ultra-high-k oxide MOS capacitors.Through post-deposition annealing,Al doping induces changes in the...An ultrathin SrTiO3 dielectric layer is optimized through Al doping to solve the problems existing in development of ultra-high-k oxide MOS capacitors.Through post-deposition annealing,Al doping induces changes in the electronic structure of SrTiO3,thereby effectively reducing leakage current to <10^-8 A/cm^2 at 0.5 MV/cm but maintains good capacitance values(ε> 80) of ultrathin SrTMO3 MOS capacitors.Strontium titanate(SrTiO3) is a high-k material but its bandgap is smaller than that of other oxide dielectrics(e.g.,SiO2,Al2 O3).Consequently,an ultrathin SrTiO3 film may have a high tunneling leakage current,which is not suitable for capacitor-based applications.To improve the performance of metal-oxide-semiconductor(MOS) capacitors using SrTiO3,an approach based on homogenous and uniform aluminum doping to SrTiO3 through co-sputtering is introduced.The bandgap of a pristine SrTiO3 film showed an increase of 0.5 eV after Al doping.Furthermore,Al doping decreased the leakage current of SrTiO3/Si-based MOS capacitors by more than five orders of magnitude(at the level of nanoampere per square centimeter).Importantly,a dielectric constant of 81.3 and equivalent oxide thickness less than 5 A were achieved in an 8-nm-thick Al-doped SrTiO3 film owing to changes in its crystal structure and conduction band edge electronic structure.Thus,the obtained data show the effectiveness of the proposed approach for solving the problems existing in the development of ultra-high-k oxide MOS capacitors.展开更多
采用一次烧成工艺制备了 Ni O、Cu O掺杂的 Sr Ti O3复合功能陶瓷 ,研究了其烧成状况、显微结构、复合功能特性及小电流区的电流 -温度关系。研究结果表明 ,掺 Ni O样品的晶粒粒度明显大于掺 Cu O样品 ;由于在烧成过程中受主杂质的行为...采用一次烧成工艺制备了 Ni O、Cu O掺杂的 Sr Ti O3复合功能陶瓷 ,研究了其烧成状况、显微结构、复合功能特性及小电流区的电流 -温度关系。研究结果表明 ,掺 Ni O样品的晶粒粒度明显大于掺 Cu O样品 ;由于在烧成过程中受主杂质的行为有所不同 ,掺 Cu O样品具有较高的晶界受主态浓度。这使得在制备条件和掺杂浓度相同的条件下 ,掺 Ni O样品和掺 Cu展开更多
SrTiO 3 capacitor varistor multifunction ceramics is fabricated by a single sintering process. The research is carried out, mainly aimed at the influence of the doped Ag + on multifunction characteristics in SrTiO 3 c...SrTiO 3 capacitor varistor multifunction ceramics is fabricated by a single sintering process. The research is carried out, mainly aimed at the influence of the doped Ag + on multifunction characteristics in SrTiO 3 ceramics and its mechanism. The results show that the density of grain boundary acceptor state increases effectively due to the fact that Sr 2+ on grain surface is substituted by doped Ag distributing at grain boundary in form of Ag + during the course of oxidizing annealing, which is proposed to be the fundamental reason for understanding the significant difference of both the dielectric properties and varistor properties in SrTiO 3 ceramics samples with various Ag + contents.展开更多
文摘The Daniels’ barium vacancy layer model of semiconducting BaTiO3 ceramics is analyzed.A grain boundary barrier model with both acceptor states of grain boundary and barium vacancy diffusion layers for the transition from PTC effect to grain boundary barrier layer (GBBL) capacitor is proposed.The proposed model solves the problem occurring in Daniels’ model and makes it possible to calculate physical properties of semiconducting BaTiO3 ceramics and relevant devices.
基金This work was supported by National Research Foundation of Korea[NRF-2019R1A2C2003804 and 2018H1D3A1A02074733]of the Ministry of Science and ICTRepublic of Korea and the technology development program(G21S272158901)funded by the Ministry of SMEs and Startups,Republic of Korea.This work was also supported by Ajou University.
文摘An ultrathin SrTiO3 dielectric layer is optimized through Al doping to solve the problems existing in development of ultra-high-k oxide MOS capacitors.Through post-deposition annealing,Al doping induces changes in the electronic structure of SrTiO3,thereby effectively reducing leakage current to <10^-8 A/cm^2 at 0.5 MV/cm but maintains good capacitance values(ε> 80) of ultrathin SrTMO3 MOS capacitors.Strontium titanate(SrTiO3) is a high-k material but its bandgap is smaller than that of other oxide dielectrics(e.g.,SiO2,Al2 O3).Consequently,an ultrathin SrTiO3 film may have a high tunneling leakage current,which is not suitable for capacitor-based applications.To improve the performance of metal-oxide-semiconductor(MOS) capacitors using SrTiO3,an approach based on homogenous and uniform aluminum doping to SrTiO3 through co-sputtering is introduced.The bandgap of a pristine SrTiO3 film showed an increase of 0.5 eV after Al doping.Furthermore,Al doping decreased the leakage current of SrTiO3/Si-based MOS capacitors by more than five orders of magnitude(at the level of nanoampere per square centimeter).Importantly,a dielectric constant of 81.3 and equivalent oxide thickness less than 5 A were achieved in an 8-nm-thick Al-doped SrTiO3 film owing to changes in its crystal structure and conduction band edge electronic structure.Thus,the obtained data show the effectiveness of the proposed approach for solving the problems existing in the development of ultra-high-k oxide MOS capacitors.
文摘采用一次烧成工艺制备了 Ni O、Cu O掺杂的 Sr Ti O3复合功能陶瓷 ,研究了其烧成状况、显微结构、复合功能特性及小电流区的电流 -温度关系。研究结果表明 ,掺 Ni O样品的晶粒粒度明显大于掺 Cu O样品 ;由于在烧成过程中受主杂质的行为有所不同 ,掺 Cu O样品具有较高的晶界受主态浓度。这使得在制备条件和掺杂浓度相同的条件下 ,掺 Ni O样品和掺 Cu
文摘SrTiO 3 capacitor varistor multifunction ceramics is fabricated by a single sintering process. The research is carried out, mainly aimed at the influence of the doped Ag + on multifunction characteristics in SrTiO 3 ceramics and its mechanism. The results show that the density of grain boundary acceptor state increases effectively due to the fact that Sr 2+ on grain surface is substituted by doped Ag distributing at grain boundary in form of Ag + during the course of oxidizing annealing, which is proposed to be the fundamental reason for understanding the significant difference of both the dielectric properties and varistor properties in SrTiO 3 ceramics samples with various Ag + contents.
