The flexoelectric effect is very strong and coupled with large strain gradients for nanoscale dielectrics. At the nanoscale, the electrostatic force cannot be ignored. In this paper, we have established the electric e...The flexoelectric effect is very strong and coupled with large strain gradients for nanoscale dielectrics. At the nanoscale, the electrostatic force cannot be ignored. In this paper, we have established the electric enthalpy variational principle for nanosized dielectrics with the strain gradient and the polarization gradient effect, as well as the effect of the electrostatic force. The complete governing equations, which include the effect of the electrostatic force, are derived from this variational principle, and based on the principle the generalized electrostatic stress is obtained, the generalized electrostatic stress contains the Maxwell stress corresponding to the polarization and strain, and stress related to the polarization gradient and strain gradient. This work provides the basis for the analysis and computations for the electromechanical problems in nanosized dielectric materials.展开更多
A new low leakage 3×VDD-tolerant electrostatic discharge(ESD)detection circuit using only low-voltage device without deep N-well is proposed in a standard 90-nm 1.2-V CMOS process.Stacked-transistors technique is...A new low leakage 3×VDD-tolerant electrostatic discharge(ESD)detection circuit using only low-voltage device without deep N-well is proposed in a standard 90-nm 1.2-V CMOS process.Stacked-transistors technique is adopted to sustain high-voltage stress and reduce leakage current.No NMOSFET operates in high voltage range and it is unnecessary to use any deep N-well.The proposed detection circuit can generate a 38 mA current to turn on the substrate triggered silicon-controlled rectifier(STSCR)under the ESD stress.Under normal operating conditions,all the devices are free from over-stress voltage threat.The leakage current is 88 nA under 3×VDD bias at 25°C.The simulation result shows the circuit can be successfully used for 3×VDD-tolerant I/O buffer.展开更多
Based on the Modified Couple Stress Theory,a functionally graded micro-beam under electrostatic forces is studied.The FGM micro-beam is made of two materials and material properties vary continuously along the beam th...Based on the Modified Couple Stress Theory,a functionally graded micro-beam under electrostatic forces is studied.The FGM micro-beam is made of two materials and material properties vary continuously along the beam thickness according to a power-law.Dynamic and static pull-in voltages are obtained and it is shown that the static and dynamic pull-in voltages for some materials cannot be obtained using classic theories and components of couple stress must be taken into account.In addition,it is shown that the values of pull-in voltages depend on the variation through the thickness of the volume fractions of the two constituents.展开更多
基金supported by the National Basic Research Program of China (Grant No. 2007CB707702)the National Natural Science Founda-tion of China (Grant Nos. 10672130 and 10972173), and Ministry of Edu-cation of China
文摘The flexoelectric effect is very strong and coupled with large strain gradients for nanoscale dielectrics. At the nanoscale, the electrostatic force cannot be ignored. In this paper, we have established the electric enthalpy variational principle for nanosized dielectrics with the strain gradient and the polarization gradient effect, as well as the effect of the electrostatic force. The complete governing equations, which include the effect of the electrostatic force, are derived from this variational principle, and based on the principle the generalized electrostatic stress is obtained, the generalized electrostatic stress contains the Maxwell stress corresponding to the polarization and strain, and stress related to the polarization gradient and strain gradient. This work provides the basis for the analysis and computations for the electromechanical problems in nanosized dielectric materials.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61076097,60936005)in part by Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China Program (Grant No. 20110203110012)
文摘A new low leakage 3×VDD-tolerant electrostatic discharge(ESD)detection circuit using only low-voltage device without deep N-well is proposed in a standard 90-nm 1.2-V CMOS process.Stacked-transistors technique is adopted to sustain high-voltage stress and reduce leakage current.No NMOSFET operates in high voltage range and it is unnecessary to use any deep N-well.The proposed detection circuit can generate a 38 mA current to turn on the substrate triggered silicon-controlled rectifier(STSCR)under the ESD stress.Under normal operating conditions,all the devices are free from over-stress voltage threat.The leakage current is 88 nA under 3×VDD bias at 25°C.The simulation result shows the circuit can be successfully used for 3×VDD-tolerant I/O buffer.
文摘Based on the Modified Couple Stress Theory,a functionally graded micro-beam under electrostatic forces is studied.The FGM micro-beam is made of two materials and material properties vary continuously along the beam thickness according to a power-law.Dynamic and static pull-in voltages are obtained and it is shown that the static and dynamic pull-in voltages for some materials cannot be obtained using classic theories and components of couple stress must be taken into account.In addition,it is shown that the values of pull-in voltages depend on the variation through the thickness of the volume fractions of the two constituents.
