This work presents a self-consistent two-dimensional(2-D) simulation method with unified physical models for different operation regimes of charge trapping memory. The simulation carefully takes into consideration the...This work presents a self-consistent two-dimensional(2-D) simulation method with unified physical models for different operation regimes of charge trapping memory. The simulation carefully takes into consideration the tunneling process, charge trapping/de-trapping mechanisms, and 2-D drift-diffusion transport within the storage layer. A string of three memory cells has been simulated and evaluated for different gate stack compositions and temperatures. The simulator is able to describe the charge transport behavior along bitline and tunneling directions under different operations. Good agreement has been made with experimental data,which hence validates the implemented physical models and altogether confirms the simulation as a valuable tool for evaluating the characteristics of three-dimensional NAND flash memory.展开更多
The aim of this study is to formulate an appropriate free energy potential for inelastic behavior of concrete and construct an elastoplastic damage model on a more rational basis. The concept of effective plastic ener...The aim of this study is to formulate an appropriate free energy potential for inelastic behavior of concrete and construct an elastoplastic damage model on a more rational basis. The concept of effective plastic energy storage rates is proposed, which are conjugate forces of hardening variables in an undamaged configuration. Then an analogy between the evolution of harden- ing variables and that of a plastic strain is used to postulate the formulation of plastic free energy. This formulation reflects the specific characteristics of a certain plasticity model, so it can serve well as a thermodynamic link between plasticity and dam- age. By combination of the general formulation of free energy with the double hardening plasticity theory and two-parameter damage expression, a thermodynamically well-founded elastoplastic damage model for concrete is constructed. The operator split algorithm is emploved, and the numerical simulations a^ree well with a series of material tests.展开更多
基金supported by National Natural Science Foundation of China (Grant No. 91230107)National Basic Research Program of China (973) (Grant No. 2013CBA01604)National High Technology Research and Development Program of China (863) (Grant No. 2015AA016501)
文摘This work presents a self-consistent two-dimensional(2-D) simulation method with unified physical models for different operation regimes of charge trapping memory. The simulation carefully takes into consideration the tunneling process, charge trapping/de-trapping mechanisms, and 2-D drift-diffusion transport within the storage layer. A string of three memory cells has been simulated and evaluated for different gate stack compositions and temperatures. The simulator is able to describe the charge transport behavior along bitline and tunneling directions under different operations. Good agreement has been made with experimental data,which hence validates the implemented physical models and altogether confirms the simulation as a valuable tool for evaluating the characteristics of three-dimensional NAND flash memory.
基金supported by the National Natural Science Foundation of China(Grant Nos.51261120374,51108336 and 51378377)
文摘The aim of this study is to formulate an appropriate free energy potential for inelastic behavior of concrete and construct an elastoplastic damage model on a more rational basis. The concept of effective plastic energy storage rates is proposed, which are conjugate forces of hardening variables in an undamaged configuration. Then an analogy between the evolution of harden- ing variables and that of a plastic strain is used to postulate the formulation of plastic free energy. This formulation reflects the specific characteristics of a certain plasticity model, so it can serve well as a thermodynamic link between plasticity and dam- age. By combination of the general formulation of free energy with the double hardening plasticity theory and two-parameter damage expression, a thermodynamically well-founded elastoplastic damage model for concrete is constructed. The operator split algorithm is emploved, and the numerical simulations a^ree well with a series of material tests.
