The time and temperature dependence of threshold voltage shift under positive-bias stress（PBS） and the following recovery process are investigated in amorphous indium-gallium-zinc-oxide（a-IGZO） thin-film transisto...The time and temperature dependence of threshold voltage shift under positive-bias stress（PBS） and the following recovery process are investigated in amorphous indium-gallium-zinc-oxide（a-IGZO） thin-film transistors. It is found that the time dependence of threshold voltage shift can be well described by a stretched exponential equation in which the time constant τ is found to be temperature dependent. Based on Arrhenius plots, an average effective energy barrier Eτ stress= 0.72 eV for the PBS process and an average effective energy barrier Eτ recovery= 0.58 eV for the recovery process are extracted respectively. A charge trapping/detrapping model is used to explain the threshold voltage shift in both the PBS and the recovery process. The influence of gate bias stress on transistor performance is one of the most critical issues for practical device development.展开更多
This paper studies the degradation of device parameters and that of stress induced leakage current （SILC） of thin tunnel gate oxide under channel hot electron （CHE） stress at high temperature by using n-channel me...This paper studies the degradation of device parameters and that of stress induced leakage current （SILC） of thin tunnel gate oxide under channel hot electron （CHE） stress at high temperature by using n-channel metal oxide semiconductor field effect transistors （NMOSFETs） with 1.4-nm gate oxides. The degradation of device parameters under CHE stress exhibits saturating time dependence at high temperature. The emphasis of this paper is on SILC of an ultra-thin-gate-oxide under CHE stress at high temperature. Based on the experimental results, it is found that there is a linear correlation between SILC degradation and Vh degradation in NMOSFETs during CHE stress. A model of the combined effect of oxide trapped negative charges and interface traps is developed to explain the origin of SILC during CHE stress.展开更多
Investigation concerning peristaltic motion of couple stress fluid is made. An incompressible couple stress fluid occupies the porous medium. Mathematical anal- ysis is presented through large wavelength and low Reyno...Investigation concerning peristaltic motion of couple stress fluid is made. An incompressible couple stress fluid occupies the porous medium. Mathematical anal- ysis is presented through large wavelength and low Reynolds number. Exact analytical expressions of axial velocity, volume flow rate, pressure gradient, and stream function are calculated as a function of couple stress parameter. The essential feature of the analysis is a full description of influence of couple stress parameter and permeability parameter on the pressure, frictional force, mechanical efficiency, and trapping.展开更多
Based on the three-dimensional dispersive finite difference time domain method and Maxwell stress tensor equation,the optical trapping properties of nanoparticle placed on the gold film with periodic circular holes ar...Based on the three-dimensional dispersive finite difference time domain method and Maxwell stress tensor equation,the optical trapping properties of nanoparticle placed on the gold film with periodic circular holes are investigated numerically. Surface plasmon polaritons are excited on the metal-dielectric interface, with particular emphasis on the crucial role in tailoring the optical force acting on a nearby nanoparticle. Utilizing a first order corrected electromagnetic field components for a fundamental Gaussian beam, the incident beam is added into the calculation model of the proposed method. To obtain the detailed trapping properties of nanoparticle, the selected calculations on the effects of beam waist radius, sizes of nanoparticle and circular holes, distance between incident Gaussian beam and gold film, material of nanoparticle and polarization angles of incident wave are analyzed in detail to demonstrate that the optical-trapping force can be explained as a virtual spring which has a restoring force to perform positive and negative forces as a nanoparticle moves closer to or away from the centers of circular holes. The results of optical trapping properties of nanoparticle in the vicinity of the gold film could provide guidelines for further research on the optical system design and manipulation of arbitrary composite nanoparticles.展开更多
The conduction mechanism of stress induced leakage current （SILC） through 2nm gate oxide is studied over a gate voltage range between 1.7V and stress voltage under constant voltage stress （CVS）. The simulation res...The conduction mechanism of stress induced leakage current （SILC） through 2nm gate oxide is studied over a gate voltage range between 1.7V and stress voltage under constant voltage stress （CVS）. The simulation results show that the SILC is formed by trap-assisted tunnelling （TAT） process which is dominated by oxide traps induced by high field stresses. Their energy levels obtained by this work are approximately 1.9eV from the oxide conduction band, and the traps are believed to be the oxygen-related donor-like defects induced by high field stresses. The dependence of the trap density on stress time and oxide electric field is also investigated.展开更多
当前,氮化镓(gallium nitride,GaN)高电子迁移率晶体管(high electron mobility transistors,HEMTs)器件已逐渐被广泛应用。然而,退化问题仍然是困扰其高可靠应用的重要因素。特别是开态应力下,器件的退化机理值得深入研究。文章基于实...当前,氮化镓(gallium nitride,GaN)高电子迁移率晶体管(high electron mobility transistors,HEMTs)器件已逐渐被广泛应用。然而,退化问题仍然是困扰其高可靠应用的重要因素。特别是开态应力下,器件的退化机理值得深入研究。文章基于实验测试及仿真,重点研究了氮化镓射频HEMT器件在开态应力下的退化现象与机理。研究结果表明,单一的高漏压应力并不会对器件带来明显退化,而高漏压与大的漏极电流结合则会对器件产生明显退化,这一影响重点集中在栅极与漏极之间的有源区。需要注意的是,栅极偏置电压在沟道电子进入栅下区域的过程中也起到了重要作用。开态应力下,栅极偏压形成的垂直电场会使得器件栅下区域损伤更加严重。文章的研究成果可以为氮化镓射频器件在复杂环境下的高可靠性应用提供重要支撑。展开更多
基金Project supported by the National Basic Research Program of China(Grant Nos.2011CB301900 and 2011CB922100)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The time and temperature dependence of threshold voltage shift under positive-bias stress（PBS） and the following recovery process are investigated in amorphous indium-gallium-zinc-oxide（a-IGZO） thin-film transistors. It is found that the time dependence of threshold voltage shift can be well described by a stretched exponential equation in which the time constant τ is found to be temperature dependent. Based on Arrhenius plots, an average effective energy barrier Eτ stress= 0.72 eV for the PBS process and an average effective energy barrier Eτ recovery= 0.58 eV for the recovery process are extracted respectively. A charge trapping/detrapping model is used to explain the threshold voltage shift in both the PBS and the recovery process. The influence of gate bias stress on transistor performance is one of the most critical issues for practical device development.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60736033 and 60506020)
文摘This paper studies the degradation of device parameters and that of stress induced leakage current （SILC） of thin tunnel gate oxide under channel hot electron （CHE） stress at high temperature by using n-channel metal oxide semiconductor field effect transistors （NMOSFETs） with 1.4-nm gate oxides. The degradation of device parameters under CHE stress exhibits saturating time dependence at high temperature. The emphasis of this paper is on SILC of an ultra-thin-gate-oxide under CHE stress at high temperature. Based on the experimental results, it is found that there is a linear correlation between SILC degradation and Vh degradation in NMOSFETs during CHE stress. A model of the combined effect of oxide trapped negative charges and interface traps is developed to explain the origin of SILC during CHE stress.
文摘Investigation concerning peristaltic motion of couple stress fluid is made. An incompressible couple stress fluid occupies the porous medium. Mathematical anal- ysis is presented through large wavelength and low Reynolds number. Exact analytical expressions of axial velocity, volume flow rate, pressure gradient, and stream function are calculated as a function of couple stress parameter. The essential feature of the analysis is a full description of influence of couple stress parameter and permeability parameter on the pressure, frictional force, mechanical efficiency, and trapping.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61701382,61601355,and 61571355)the China Postdoctoral Science Foundation(Grant No.2016M602770)the Xi’an Technological University Principal Foundation Key Project,China(Grant No.XAGDXJJ18001)
文摘Based on the three-dimensional dispersive finite difference time domain method and Maxwell stress tensor equation,the optical trapping properties of nanoparticle placed on the gold film with periodic circular holes are investigated numerically. Surface plasmon polaritons are excited on the metal-dielectric interface, with particular emphasis on the crucial role in tailoring the optical force acting on a nearby nanoparticle. Utilizing a first order corrected electromagnetic field components for a fundamental Gaussian beam, the incident beam is added into the calculation model of the proposed method. To obtain the detailed trapping properties of nanoparticle, the selected calculations on the effects of beam waist radius, sizes of nanoparticle and circular holes, distance between incident Gaussian beam and gold film, material of nanoparticle and polarization angles of incident wave are analyzed in detail to demonstrate that the optical-trapping force can be explained as a virtual spring which has a restoring force to perform positive and negative forces as a nanoparticle moves closer to or away from the centers of circular holes. The results of optical trapping properties of nanoparticle in the vicinity of the gold film could provide guidelines for further research on the optical system design and manipulation of arbitrary composite nanoparticles.
文摘The conduction mechanism of stress induced leakage current （SILC） through 2nm gate oxide is studied over a gate voltage range between 1.7V and stress voltage under constant voltage stress （CVS）. The simulation results show that the SILC is formed by trap-assisted tunnelling （TAT） process which is dominated by oxide traps induced by high field stresses. Their energy levels obtained by this work are approximately 1.9eV from the oxide conduction band, and the traps are believed to be the oxygen-related donor-like defects induced by high field stresses. The dependence of the trap density on stress time and oxide electric field is also investigated.
文摘当前,氮化镓(gallium nitride,GaN)高电子迁移率晶体管(high electron mobility transistors,HEMTs)器件已逐渐被广泛应用。然而,退化问题仍然是困扰其高可靠应用的重要因素。特别是开态应力下,器件的退化机理值得深入研究。文章基于实验测试及仿真,重点研究了氮化镓射频HEMT器件在开态应力下的退化现象与机理。研究结果表明,单一的高漏压应力并不会对器件带来明显退化,而高漏压与大的漏极电流结合则会对器件产生明显退化,这一影响重点集中在栅极与漏极之间的有源区。需要注意的是,栅极偏置电压在沟道电子进入栅下区域的过程中也起到了重要作用。开态应力下,栅极偏压形成的垂直电场会使得器件栅下区域损伤更加严重。文章的研究成果可以为氮化镓射频器件在复杂环境下的高可靠性应用提供重要支撑。
