A physical model for mobility degradation by interface-roughness scattering and Coulomb scattering is proposed for SiGe p-MOSFET with a high-k dielectric/SiO2 gate stack. Impacts of the two kinds of scatterings on mob...A physical model for mobility degradation by interface-roughness scattering and Coulomb scattering is proposed for SiGe p-MOSFET with a high-k dielectric/SiO2 gate stack. Impacts of the two kinds of scatterings on mobility degradation are investigated. Effects of interlayer （SiO2） thickness and permittivities of the high-k dielectric and interlayer on carrier mobility are also discussed. It is shown that a smooth interface between high-k dielectric and interlayer, as well as moderate permittivities of high-k dielectrics, is highly desired to improve carriers mobility while keeping alow equivalent oxide thickness. Simulated results agree reasonably with experimental data.展开更多
We theoretically study the influence of spacer layer thickness fluctuation（SLTF） on the mobility of a twodimensional electron gas（2DEG） in the modulation-doped Al x Ga 1 x As/GaAs/Al x Ga 1 x As quantum well.The d...We theoretically study the influence of spacer layer thickness fluctuation（SLTF） on the mobility of a twodimensional electron gas（2DEG） in the modulation-doped Al x Ga 1 x As/GaAs/Al x Ga 1 x As quantum well.The dependence of the mobility limited by SLTF scattering on spacer layer thickness and donor density are obtained.The results show that SLTF scattering is an important scattering mechanism for the quantum well structure with a thick well layer.展开更多
We have theoretically studied the mobility limited by interface roughness scattering on two-dimensional electrons gas（2DEG） at a single heterointerface（triangle-shaped quantum well）.Our results indicate that,like ...We have theoretically studied the mobility limited by interface roughness scattering on two-dimensional electrons gas（2DEG） at a single heterointerface（triangle-shaped quantum well）.Our results indicate that,like the interface roughness scattering in a square quantum well,the roughness scattering at the Al_xGa_（1-x）As/GaAs heterointerface can be characterized by parameters of roughness height A and lateral A,and in addition by electric field F.A comparison of two mobilities limited by the interface roughness scattering between the present result and a square well in the same condition is given.展开更多
Taking into account the quantum size effects and considering three types of scattering from bulk impurities,rough surface and rough interfaces, we use quantum-statistical Green's function approach and Kubo theory ...Taking into account the quantum size effects and considering three types of scattering from bulk impurities,rough surface and rough interfaces, we use quantum-statistical Green's function approach and Kubo theory to calculate the electronic conductivity and the giant magnetoresistance in magnetic multilayered cylindrical systems. It is found that in the limit of weakly scattering from impurities surface and interfaces, the total conductivity is given by a sum of conductivities of all the subbands and two spin-channels. For each subband and each spin-channel the scattering rate due to the impurities, surface and interfaces is added up.展开更多
In this paper, the superconducting order parameter and the energy spectrum of the Bogoliubov excitations are obtained from the Bogoliubov-de Gennes （BdG） equation for a ferromagnetic superconductor （FS）. Taking in...In this paper, the superconducting order parameter and the energy spectrum of the Bogoliubov excitations are obtained from the Bogoliubov-de Gennes （BdG） equation for a ferromagnetic superconductor （FS）. Taking into account the rough interface scattering effect, we calculate the shot noise and the differential conductance of the normalmetal insulator ferromagnetic superconductor junction. It is shown that the exchange energy Eh in FS can lead to splitting of the differential shot noise peaks and the conductance peaks. The energy difference between the two splitting peaks is equal to 2Eh. The rough interface scattering strength results in descent of conductance peaks and the shot noise-to-current ratio but increases the shot noise.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 60776016）, the RGC of HKSAR, China （Grant No HKU7142/05E）, and Open Foundation of State Key Laboratory of Advanced Technology for Materials Synthesis and Processing （Grant No WUT2006M02）.
文摘A physical model for mobility degradation by interface-roughness scattering and Coulomb scattering is proposed for SiGe p-MOSFET with a high-k dielectric/SiO2 gate stack. Impacts of the two kinds of scatterings on mobility degradation are investigated. Effects of interlayer （SiO2） thickness and permittivities of the high-k dielectric and interlayer on carrier mobility are also discussed. It is shown that a smooth interface between high-k dielectric and interlayer, as well as moderate permittivities of high-k dielectrics, is highly desired to improve carriers mobility while keeping alow equivalent oxide thickness. Simulated results agree reasonably with experimental data.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60976008,61006004,61076001,and10979507)the National Basic Research Program of China (Grant No. A000091109-05)the National High Technology Research and Development Program of China (Grant No. 2011AA03A101)
文摘We theoretically study the influence of spacer layer thickness fluctuation（SLTF） on the mobility of a twodimensional electron gas（2DEG） in the modulation-doped Al x Ga 1 x As/GaAs/Al x Ga 1 x As quantum well.The dependence of the mobility limited by SLTF scattering on spacer layer thickness and donor density are obtained.The results show that SLTF scattering is an important scattering mechanism for the quantum well structure with a thick well layer.
文摘We have theoretically studied the mobility limited by interface roughness scattering on two-dimensional electrons gas（2DEG） at a single heterointerface（triangle-shaped quantum well）.Our results indicate that,like the interface roughness scattering in a square quantum well,the roughness scattering at the Al_xGa_（1-x）As/GaAs heterointerface can be characterized by parameters of roughness height A and lateral A,and in addition by electric field F.A comparison of two mobilities limited by the interface roughness scattering between the present result and a square well in the same condition is given.
文摘Taking into account the quantum size effects and considering three types of scattering from bulk impurities,rough surface and rough interfaces, we use quantum-statistical Green's function approach and Kubo theory to calculate the electronic conductivity and the giant magnetoresistance in magnetic multilayered cylindrical systems. It is found that in the limit of weakly scattering from impurities surface and interfaces, the total conductivity is given by a sum of conductivities of all the subbands and two spin-channels. For each subband and each spin-channel the scattering rate due to the impurities, surface and interfaces is added up.
文摘In this paper, the superconducting order parameter and the energy spectrum of the Bogoliubov excitations are obtained from the Bogoliubov-de Gennes （BdG） equation for a ferromagnetic superconductor （FS）. Taking into account the rough interface scattering effect, we calculate the shot noise and the differential conductance of the normalmetal insulator ferromagnetic superconductor junction. It is shown that the exchange energy Eh in FS can lead to splitting of the differential shot noise peaks and the conductance peaks. The energy difference between the two splitting peaks is equal to 2Eh. The rough interface scattering strength results in descent of conductance peaks and the shot noise-to-current ratio but increases the shot noise.
