A new method for extracting the channel-length reduction and thegate-voltage-dependent series resistance of counter-implanted p-MOSFETs

Based on the channel-resistance measurement, a new method for extracting the channel-length reduction (ΔL_jj) and the gate-voltage-dependent source/drain resistance (R_SD) of counter-implanted p-MOSFETs is proposed, in which the necessity of the applying substrate bias is demonstrated and an empirical relationship between poly-Si gate length (L_M) and device structure parameters for ΔL_jj extraction is provided. This is the first attempt to extract the basic parameters of counter-implanted p-MOSFETs with the LDD structure. Numerical analysis using two-dimensional (2-D) device simulator has been used to verify the proposed extraction method. Furthermore, an improved approach to extract R_SD is also presented. Both numerical analysis and experimental results show good accuracy of our proposed method     

A new method for extracting the effective channel length of MOSFETs

A new and simple method to extract the effective channel length L_eff of metal-oxide superconductor field effect transistor (MOSFET)s is presented. The method, which is developed based on an auxiliary integral function, has the advantage of determining the value of L_eff not influenced by the series resistances of the MOSFET. The method is tested in the environments of device simulation and measurements. In addition, comparison is made between the results obtained from the present method and a widely used L_eff extraction method.     

A new charge pumping method for determining the spatialdistribution of hot-carrier-induced fixed charge in p-MOSFETs

A charge pumping method is proposed for the direct measurement of the hot-carrier-induced fixed charge near the drain junction of p-MOSFETs. By holding the rising and falling slopes of the gate pulse constant and then varying the highest and lowest levels, the local threshold and local flatband voltages are readily obtained. The spatial distribution of fixed charges is directly calculated from the changes that occur in these curves after the application of stress. This method is quite simple and, specifically, requires no information about impurity concentrations in the substrate. The validity and reliability of the method have been supported by computer simulations     

A new method for extracting the rules of the Fuzzy Associative Memory

Based on the features of the Fuzzy Associative Memory (FAM), a method for extracting the FAM rules is proposed. When the partition of the input space is available, the extraction of the FAM rules can be converted into the plane clustering. When the number of the linguistic values of the output variable is given, the steady-state rule can be first obtained with the one-dimensional frequency histograms of the input and output variables, and then the extraction of the remaining rules can be converted into the partition of the input space with the tree classifier through clustering in the input-output product space the planes vertical to the output axis. Finally the property of the method is tested with an example of the truck backer-upper control system.     

A novel method for extracting the metallurgical channel length ofMOSFETs using a single device

A new charge-pumping method with dc source/drain biases and specified gate waveforms is proposed to extract the metallurgical channel length of MOSFETs by using a single device. Using two charge-pumping currents of a single nMOSFET measured under different V _GL (V_GH for pMOSFETs), the metallurgical channel length can be easily extracted with an accuracy of 0.02 μm. It is shown that the proposed novel method is self-consistent with the results obtained by the charge-pumping current measured from multidevices under different gate pulse waveforms and bias conditions     

A new model for the post-stress interface trap generation inhot-carrier stressed p-MOSFETs

A new insight into the post-stress interface trap (N_it) generation in hot-electron stressed p-MOSFETs is presented. N_it generation is suppressed for positive oxide field but enhanced for negative oxide field. This observation provides strong support for a two-carrier model, involving the recombination between trapped electrons and inversion holes. While post-stress interface instability has generally been associated with hole trapping and hydrogen transport, our results clearly show the importance of electron traps on the long term stability of the Si-SiO₂ interface, and that the two-carrier model provides a consistent explanation for post-stress N_it generation in p-MOSFETs stressed under hot-electron injection     

A new empirical large-signal model for enhancement-mode AlGaAs/InGaAs pHEMTs

We propose a new large-signal model for AlGaAs/InGaAs pHEMTs, which can simulate the device microwave output power, non-linear characteristics at arbitrary bias points. This model includes a new drain current equation, which is extracted from its derivatives. In addition, gate-to-source and gate-to-drain capacitances are also characterized versus the function of gate and drain biases. The parameter extraction procedure is addressed for the enhancement-mode pHEMTs, which offers an attractive solution for handset power amplifier application because of its positive bias characteristics. Finally, measured and model-predicted dc I–V, S-parameters, and power performance have been compared.     

A new method of channel identification

A method of channel identification is proposed that exploits the spectral correlation properties of pulse- and carrier-modulated signals to identify channels in the presence of arbitrary noise and nearly arbitrary interference. Although a pilot or training signal is required, no replica of the transmitted pilot/training signal is needed at the receiver. The price paid for this simplicity and the tolerance to extreme channel corruption from noise or interference is that the method is slow. That is, relatively long averaging times are needed for measurement of the spectral correlation of the received signal     

A new process-variation-immunity method for extracting capacitancecoupling coefficients in flash memory cells

Overestimation of capacitance coupling coefficients in flash memory cells is encountered in the subthreshold slope method. By means of a two-parameters subthreshold current model I_D=I₀ exp[q(V_GB - nV_SB)/nkT], a mathematical formulation of the subthreshold swing ratio in the subthreshold slope method is constructed to isolate the measurement errors caused by process variations from the errors traditionally caused by bulk capacitance coupling. To minimize the effect of process variations, a new method is developed based on the model. In this method, the control gate voltage shift due to weak body effect is measured in flash memory cells in subthreshold, while the corresponding slope factor n is adequately deduced from threshold voltage versus source-to-substrate bias measurement in dummy devices. The corrected capacitance coupling coefficients show large improvements compared to the design values, and the updated errors are found to be close to that caused solely by bulk capacitance coupling. The method is also fast since only a small source-to-substrate bias of 0.1 V is needed for implementation of weak body effect, and thereby it can be used as an in-line monitor of capacitance coupling coefficients     

一种用于信道分集性能研究的新方法

对于无线通信系统来说,信道分集是实现可靠通信、提高通信性能的有效方法.目前,分集复用折衷性能是衡量不同信道分集技术性能的常用方法,该法仅适应于高信噪比情况.本文基于信道分集因子统计特性从一个新的角度对信道分集进行了研究,针对传统信道分集技术提出了一种新的信道分集性能研究方法,理论分析及仿真结果表明方法是有效的.     

A new method to determine MOSFET channel length

A new method is proposed to electrically determine MOS transistor channel length with both accuracy and convenience. Based on the linear region relationship between effective channel length Leffand channel resistance Rchanof an MOS transistor, this method determines Leffby applying relatively large but constant gate voltage to eliminate threshold voltage determination and takes into account external resistance. Comparison of this method with SEM measurement shows very good agreement (within ±0.1 µm resolution limit of our SEM technique).     

Optimization and realization of sub-100-nm channel length singlehalo p-MOSFETs

Single halo p-MOSFETs with channel lengths down to 100 nm are optimized, fabricated, and characterized as part of this study. We show extensive device characterization results to study the effect of large angle V_T adjust implant parameters on device performance and hot carrier reliability. Results on both conventionally doped and single halo p-MOSFETs have been presented for comparison purposes     

Model for the channel-implanted enhancement-mode IGFET

A simple dc four-terminal "channel-implanted model" is developed for the enhancement-mode IGFET. The model accurately predicts the dependence of transistor threshold voltage and current gain on substrate bias. Modeled and measured threshold voltages are shown to agree to within 25 mV across a 15-V range of VSB. Modeled and measured transistor currents agree to within 5 percent across a 10-V range of VSBfor medium- to long-channel length transistors (L_{drawn} ge 2.5µm). The channel impurity profile is approximated as a constant effective impurity concentration NAEextending from the semiconductor surface through the implanted region to an effective implant depth XDE("box" profile approximation). At depths greater than XDE, the bulk substrate impurity concentration is approximated as a constant, NA. The model is composed of two threshold voltage equations, three drain current equations, two saturation voltage equations, and two boundary equations. All first-order model equations and all of their first derivatives are continuous at all boundaries. The model's continuity and its accuracy make it useful for circuit simulation. Extrapolation of channel concentration profile parameters NAE, XDE, and NAfrom measured threshold voltages yields information on implant profile and on field-implant impurity encroachment into the transistor channel.     

一种基于信道估计的MIMO雷达目标角度估计方法

MIMO雷达是一种新体制雷达。它的信号传输矩阵包含了我们需要的目标信息,如角度信息。本文首先建立了包含目标角度信息的MIMO雷达接收信号模型。然后根据MIMO雷达接收信号的统计特性,提出了新的MIMO雷达传输信道的估计方法,然后从传输矩阵中估计出目标角度信息。最后,我们通过仿真实验验证了本文方法的有效性。     

A new method for the integration of modulation and channel codingin an ARQ protocol

A method for the integration of the modulation operation in an automatic-repeat-request (ARQ) scheme is described. This method uses a memory for the successive transmissions of a codeword and, through a suitable encoding operation, the Euclidean distances among the codewords are significantly increased with the number of transmissions. The application of the described method to some different modulation schemes, such as M-ary PSK with M>2 and continuous-phase frequency shift keying modulation, is described. The optimum combination of the modulation and channel coding operations for some short block codes is also presented. The results of the theoretical analysis show that the method described permits improving both the error probability and the throughput of an ARQ protocol with respect to similar schemes     

A new method for predicting the channel estimate influence onperformance of TDMA mobile radio systems

Receivers for time division multiple access mobile radio systems usually consist of two functional blocks: A channel estimator and an equalizer. We present a new method for predicting the channel estimate influence on performance of such receivers operating over frequency selective time-varying Rayleigh fading channels. The method can be applied to optimize system parameters. It is shown that global receiver performance can be analytically expressed in terms of the performance characteristics of two blocks considered disjointly, i.e. the equalizer operating over a perfectly known channel and the channel estimator operating over a time-varying channel. The analysis leads to expressions of the error probabilities in a form that can conveniently be used in numerical work. The results obtained from Monte Carlo evaluation agree well with the analytical evaluation of the error probability derived from the proposed method with the benefit of the low complexity and rapidity for the latter     

A new method to electrically determine effective MOSFET channel width

A new, easy, and accurate electrical measurement method for determining process bias of MOSFET channel width is proposed. This method is based on the linear relationship between the effective width and the channel conductance (or drain current) of a MOSFET operating in the linear region. Constant and sufficiently high gate voltages compared with the threshold voltage of the device are used in the measurement to minimize the error due to the threshold-voltage variation with W in narrow-width devices. The validity of the method is supported by identical results obtained using different gate voltages.     

一种快速光栅条纹中心亚像素坐标提取方法

光栅条纹中心的精确提取会直接影响到线结构光视觉的测量与重建精度。为了解决传统的Steger算法计算量大,且在光条不均匀时提取不精确等问题。基于改进的Steger算法,提出了针对光栅条纹中心的快速亚像素坐标提取方法。通过高斯滤波、形态学等方法得到去复杂背景的激光条纹图像,用自适应阈值法缩小ROI区域,用霍夫变化求取光栅边缘线,求出边缘线中点,然后直线拟合,最后用改进算法提取中心坐标。实验结果表明:与模板法、传统Steger算法等光栅条纹中心提取算法相比,算法的鲁棒性更强,最大提取误差在0.3个像素,平均误差为0.1个像素,平均运行时间相比传统算法减少0.4 s。     

A charge-sheet analysis of short-channel enhancement-mode MOSFETs

A charge-sheet analysis of the short-channel MOSFET is presented. The expression achieved for the drain current, which takes into account both the drift and the diffusion components and also mobility degradation effects, holds in the strong-inversion, weak-inversion, and saturation regimes of the device operation, and results in a continuous function of all bias voltages. The model predicts an exponential dependence of the drain current on drain voltage in weak inversion and the threshold dependence on both channel length and drain voltage. Moreover, the proposed approach predicts results which satisfactorily compare with numerical simulations obtained from the two-dimensional analyzer MINIMOS and experimental data.     

A new lower bound for the channel assignment problem

The strength of lower bounds for the span in channel assignment problems is discussed with reference to standard benchmark problems. It is shown that in some circumstances current bounds are capable of very significant improvement. The use of methods from mathematical programming is outlined and a new lower bound applicable to cellular problems is presented