A model based on analysis of the self-consistent Poisson-Schrodinger equation is proposed to investigate the tunneling current of electrons in the inversion layer of a p-type metal-oxide-semiconductor （MOS） structur...A model based on analysis of the self-consistent Poisson-Schrodinger equation is proposed to investigate the tunneling current of electrons in the inversion layer of a p-type metal-oxide-semiconductor （MOS） structure. In this model, the influences of interface trap charge （ITC） at the Si-SiO2 interface and fixed oxide charge （FOC） in the oxide region are taken into account, and one-band effective mass approximation is used. The tunneling probability is obtained by employing the transfer matrix method. Further, the effects of in-plane momentum on the quantization in the electron motion perpendicular to the Si-SiO2 interface of a MOS device are investigated. Theoretical simulation results indicate that both ITC and FOC have great influence on the tunneling current through a MOS structure when their densities are larger than l012 cm 2, which results from the great change of bound electrons near the Si-SiO2 interface and the oxide region. Therefore, for real ultrathin MOS structures with ITC and FOC, this model can give a more accurate description for the tunneling current in the inversion layer.展开更多
A diagram representation method is proposed to interpret the complicated charge pumping（CP） processes. The fast and slow traps in CP measurement are defined.Some phenomena such as CP pulse rise/fall time dependence,...A diagram representation method is proposed to interpret the complicated charge pumping（CP） processes. The fast and slow traps in CP measurement are defined.Some phenomena such as CP pulse rise/fall time dependence, frequency dependence,the voltage dependence for the fast and slow traps,and the geometric CP component are clearly illustrated at a glance by the diagram representation.For the slow trap CP measurement,there is a transition stage and a steady stage due to the asymmetry of the electron and hole capture,and the CP current is determined by the lower capturing electron or hole component.The method is used to discuss the legitimacy of the newly developed modified charge pumping method.展开更多
In this work, the trap-assisted tunneling（TAT） mechanism is modeled as a two-step physical process for charge trapping memory（CTM）. The influence of the TAT mechanism on CTM performance is investigated in consider...In this work, the trap-assisted tunneling（TAT） mechanism is modeled as a two-step physical process for charge trapping memory（CTM）. The influence of the TAT mechanism on CTM performance is investigated in consideration of various trap positions and energy levels. For the simulated CTM structure, simulation results indicate that the positions of oxide traps related to the maximum TAT current contribution shift towards the substrate interface and charge storage layer interface during time evolutions in programming and retention operations, respectively. Lower programming voltage and retention operations under higher temperature are found to be more sensitive to tunneling oxide degradation.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 61076055)the Program for Innovative Research Team of Zhejiang Normal University of China (Grant No. 2007XCXTD-5)the Open Program of Surface Physics Laboratory of Fudan University, China (Grant No. FDSKL2011-04)
文摘A model based on analysis of the self-consistent Poisson-Schrodinger equation is proposed to investigate the tunneling current of electrons in the inversion layer of a p-type metal-oxide-semiconductor （MOS） structure. In this model, the influences of interface trap charge （ITC） at the Si-SiO2 interface and fixed oxide charge （FOC） in the oxide region are taken into account, and one-band effective mass approximation is used. The tunneling probability is obtained by employing the transfer matrix method. Further, the effects of in-plane momentum on the quantization in the electron motion perpendicular to the Si-SiO2 interface of a MOS device are investigated. Theoretical simulation results indicate that both ITC and FOC have great influence on the tunneling current through a MOS structure when their densities are larger than l012 cm 2, which results from the great change of bound electrons near the Si-SiO2 interface and the oxide region. Therefore, for real ultrathin MOS structures with ITC and FOC, this model can give a more accurate description for the tunneling current in the inversion layer.
基金Project supported by the Micro/Nano-Electronics Science and Technology Innovation Platform of Fudan University,National Natural Science Foundation of China(No.60936005)the National VLSI Project(No.2009ZX02035-003).
文摘A diagram representation method is proposed to interpret the complicated charge pumping（CP） processes. The fast and slow traps in CP measurement are defined.Some phenomena such as CP pulse rise/fall time dependence, frequency dependence,the voltage dependence for the fast and slow traps,and the geometric CP component are clearly illustrated at a glance by the diagram representation.For the slow trap CP measurement,there is a transition stage and a steady stage due to the asymmetry of the electron and hole capture,and the CP current is determined by the lower capturing electron or hole component.The method is used to discuss the legitimacy of the newly developed modified charge pumping method.
基金supported by the National Natural Science Foundation of China(Grant Nos.61404005,61421005,and 91434201)
文摘In this work, the trap-assisted tunneling（TAT） mechanism is modeled as a two-step physical process for charge trapping memory（CTM）. The influence of the TAT mechanism on CTM performance is investigated in consideration of various trap positions and energy levels. For the simulated CTM structure, simulation results indicate that the positions of oxide traps related to the maximum TAT current contribution shift towards the substrate interface and charge storage layer interface during time evolutions in programming and retention operations, respectively. Lower programming voltage and retention operations under higher temperature are found to be more sensitive to tunneling oxide degradation.
