Papers by Author: He Ming Zhang

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Authors: Hui Yong Hu, Liu Sun, He Ming Zhang, Jian Jun Song
Abstract: A low-power, high linearity Gm-C filter is presented and designed.The input transistors of Gm is biased in linear region, and drain-source voltage is constant through feedback loop. The filter is designed in SMIC 0.18μm Mixed Signal CMOS PDK (Process Design Kit) with cutoff frequency 15.74 MHz, Passband ripple less than 0.2dB,while dissipating 2.5mW. It can be used as Baseband filter in RF system.
Authors: Shan Shan Qin, He Ming Zhang, Hui Yong Hu, Xiao Bo Xu, Xiao Yan Wang
Abstract: A subthreshold current model for fully depleted strained Si on insulator (FD SSOI) MOSFET is developed by solving the two-dimensional (2D) Poisson equation and the conventional drift-diffusion theory. Model verification is carried out using device simulator ISE. Good agreement is obtained between the model’s calculations and the simulated results. This subthreshold current model provides valuable reference to the FD-SSOI MOSFET design.
Authors: Shan Shan Qin, He Ming Zhang, Hui Yong Hu, Xiao Yan Wang, Guan Yu Wang
Abstract: Threshold voltage models for both buried channel and surface channel for the dual-channel strained Si/strained Si1-xGex/relaxd Si1-yGey(s-Si/s-SiGe/Si1-yGey) p-type metal-oxide-semiconductor field-effect transistor (PMOSFET) are presented in this paper. And the maximum allowed thickness of s-Si is given, which can ensure that the strong inversion appears earlier in the buried channel (compressive strained SiGe) than in the surface channel, because the hole mobility in the buried channel is higher than that the surface channel. They offer a good accuracy as compared with the results of device simulator ISE.
Authors: Jian Jun Song, Shuai Lei, He Ming Zhang, Hui Yong Hu
Abstract: Applying KP theory combined with deformation potential we obtained the valence band structure, and based on this result we calculated the orientation-dependent effective mass which is also called conductivity effective mass in strained Si1-xGex/(001)Si in this research, and furthermore ,we established the scattering rate model by using the density-of-states effective mass. On the basis of conductivity effective mass and scattering rate model, utilizing analytical method and relaxation time approximation we obtained the dependence of the value of hole mobility on stress and doping concentration in strained Si1-xGex/(001)Si along different crystal orientations. Compare to the unstrained Si, the anisotropy of hole mobility is more obvious in strained Si1-xGex/(001)Si, for example, It shows that under the same stress and doping concentration (Ni=1x1014cm-3, x=0.4), the value of hole mobility along [010] crystal orientation is visibly higher than other crystal orientations. This result can provide valuable references to the research of hole mobility of strained Si1-xGex materials and the design of devices.
Authors: Xiao Bo Xu, He Ming Zhang, Hui Yong Hu, Shan Shan Qin, Jiang Tao Qu
Abstract: An analytical expression for collector resistance of a novel vertical SiGe partially-depleted accumulation-subcollector HBT on thin SOI is obtained. Supported by simulation result, the resistance decreases quickly with the increase of substrate-collector bias and improves the transit frequency dramatically. The model is found to be significant in the design and simulation of 0.13 μm millimeter wave SiGe SOI BiCMOS technology.
Authors: Jian Jun Song, Liu Sun, He Ming Zhang, Hui Yong Hu
Abstract: This paper presents a new enhanced phase switching 15/16 dual-modulus prescaler. One more divide-by-2 stage was employed in the design compare to the conventional phase switching architecture. Since the operating speed of phase switching circuit is obviously reduced. The inverse phase switching sequence was employed in this circuit to implement glitch-free phase switching. Further more, a dynamic load master-slave DFF was employed as the first divide-by-2 stage which can increase the operating frequency of prescaler. Measurement result shows, this dual-modulus prescaler can operate at 3GHz-200MHz with 2.8mA supply current at 1.8V power supply.
Authors: Cheng Wang, He Ming Zhang, Rong Xi Xuan, Hui Yong Hu
Abstract: Si-based strained technology is currently an important topic of concern in the microelectronics field. The stress-induced enhancement of electron mobility contributes to the improved performance of Si-based strained devices. In this paper, Based on both the electron effective mass and the scattering rate models for strained-Si1-xGex/Si (101), an analytical electron mobility model for biaxial compressive strained-Si1-xGex /Si (101) is presented. The results show that the stress doesn’t make the electron mobility increased, but the electron mobility for [100] and [001] orientations decrease with increasing Ge fraction x, especially for [010] orientation expresses a sharp decrease. This physical phenomenon can be explained as: Although the applied stress (the higher the Ge fraction, the greater the applied stress) can enhance the electron mobility, alloy disorder scattering rate markedly increase. Overall the electron mobility decreases instead. The above result suggests that not all the mobilities for Si-based strained materials enhance with the stress applied. For the biaxial strained-SiGe material represented by Ge fraction, the effect of alloy disorder scattering on the enhancement of mobility must be concerned. The result can provide theoretical basis for the understanding of the improved physical characterizations and the enhanced mobility for Si-based strained materials.
Authors: Yu Chen Li, He Ming Zhang, Hui Yong Hu, Yu Ming Zhang, Bin Wang, Chun Yu Zhou, Yong Le Lou
Abstract: The effect of high-k material on gate threshold voltage for double gate tunnel field-effect transistor (DG-TFET) is studied in this paper. By physically derived the model of threshold voltage for DG-TFET, the quantitative relationship between threshold voltage and gate length is also discussed. It is shown that the proposed model is consistent with the simulation results, and can also easily predict the improved performance on the gate threshold voltage when using high-κ dielectrics and the limited effect on gate threshold voltage when changing the gate length.
Authors: Jiu Hua An, He Ming Zhang, Jian Jun Song, Xiao Yan Wang
Abstract: There has been much interest in the Si-based strained technology lately. The improvement of strained-Si device performance is due to the enhancement of the mobility, so the further study on mobility is essential in both theory and practice aspects. In this paper, an analytical model of the electron mobility of strained-Si material, such as biaxial tensile strained-Si material grown on relaxed Si1-xGex (0≤x≤0.6) substrates, as a function of strain and different orientations is obtained. The results show that the electron mobilities for [100] and [010] orientations increase rapidly with increasing Ge fraction x, and there is no electron mobility enhancement for [001] orientation in comparison to relaxed Si material.
Authors: Hui Yong Hu, Shuai Lei, He Ming Zhang, Rong Xi Xuan, Bin Shu
Abstract: Solving the Schrödinger equation with strain Hamiltonian and combining with KP theory, we obtained the conductivity effective mass and density of states effective mass of strained Si1-xGex(001) in this paper. On the basis of conductivity effective mass and density of states effective mass, considered of Fermi golden rule and Boltzman collision term approximation theory, scattering rate model was established in strained Si1-xGex(001). Based on the conductivity effective mass and scattering rate models we discussed the dependence of electron mobility on stress and doping concentration in strained Si1-xGex(001), it shows that electron mobility decrease with the increasing of stress and doping concentration. This result can provide valuable references to the research of electron mobility of strained Si1-xGex materials and the design of devices.
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