Rigorous analysis of planar MIS transmission lines

The realisation of distributed microwave integrated circuits can be expected by using very low phase velocity propagation modes on MIS and Schottky planar transmission lines. Up to now, the frequency behaviour of such lines has been obtained by using analytical models. We present a rigorous analysis of a MIS microstrip line, the validity of which is testified by comparison to experimental values.     

Propagation characteristics of superconducting microstrip lines

The modified spectral-domain approach is applied to study the propagation characteristics of high temperature superconducting microstrip lines whose signal strip and ground plane are of arbitrary thickness. In this study, numerical results for effective dielectric constant, attenuation constant, and strip current distribution are presented to discuss the effects due to frequency, temperature, strip thickness, and substrate loss tangent. In particular, the conductor and dielectric attenuation constants of superconducting microstrip line are depicted separately to discuss the mechanism of the line losses. A comparison with published theoretical and experimental results is also included to check the accuracy of the new approach's results     

Propagation in a two-dimensional periodic random medium withinhomogeneous particle distribution

The behavior of electromagnetic waves when propagating in a periodic random medium, such as a row-structured canopy, is considered. The semideterministic character of the particle distributions is represented by nonuniform extinction and phase matrices and the problem is formulated by the radiative transfer equation. Solution of the radiative transfer equation is pursued both iteratively and by using a numerical technique, based on the discrete-ordinate approximation and Taylor series expansion. It is shown that the numerical solution for the periodic canopy is computationally efficient, and a closed-form for the first-order solution (iterative approach) of the radiative transfer equation is obtained for periodic cases. The analytical and numerical results are compared with transmission measurements at L- and C-band frequencies for a corn canopy for a variety of canopy conditions, with good agreement     

Using the MIS capacitor for doping profile measurements with minimal interface state error

Doping profiles can be measured to best advantage by using MIS capacitors when one is interested in the profile either very close to the semiconductor surface or in very heavily doped semiconductors. This paper shows both experimentally and theoretically that the major error caused by interface states can be minimized by using either the pulsed capacitance voltage technique or by the second-harmonic profiling technique. This makes possible profile measurements in MIS capacitors even with very large interface state densities, and makes it advantageous to use MIS capacitors for the express purpose of profile measurements. The minimization of interface state errors is contingent upon using a high enough measurement frequency. Moreover, the closer to the interface that the profile is desired, the higher the frequency must be. At high enough frequencies, the intrinsic resolution of the method allows accurate measurement of the doping profile only to within a few extrinsic Debye lengths of the Si-SiO2interface. Curves are presented indicating the closeness to the interface attainable within a 2 percent profile error as a function of measurement frequency, doping level, and temperature. Comparison of experimental measurements with theory on uniformly doped samples at 5 and 30 MHz substantiates our analysis of interface state effects. Finally, a nonuniform profile is measured to illustrate the method.     

Determination of the semiconductor doping profile right up to its surface using the MIS capacitor

A new method has been developed by which the doping profile of the semiconductor can be obtained right up to its surface. Contrary to the well known dC/dV-method, which is valid only in the depletion range, we have considered the majority carriers in deriving relations for doping density as well as distance from the semiconductor surface, in terms of the space charge capacitance and its derivative with respect to the surface potential. This method can be realized experimentally on any MIS structure. Measurements on MOS capacitors with steam grown oxides showed a drooping profile towards the SiSiO₂ interface for boron doped and a rising one for phosphorus doped silicon. Post-oxidation annealing in dry nitrogen at 1200°C produced a uniform profile for phosphorus doped silicon.     

Propagation characteristics of coplanar-type transmission lineswith lossy media

Lossy coplanar-type transmission lines are analyzed based on the hybrid-mode formulation by combining the spectral-domain approach with the perturbation method. Introducing a finite thickness of metallization and choosing the proper basis functions for the thick conductor model prevent the integrals used for calculating the conductor losses from becoming singular when evaluated at the conductor edge. An orthogonality relation is used to reduce the double infinite or semi-infinite integral to a single integral, thus reducing the computation effort drastically. Numerical computations by new basis functions for the thick conductor show convergence rates as fast as those for the zero-thickness cases. Numerical results include the effective dielectric constants, characteristic impedances, and total losses (conductor and dielectric losses) for slot lines and symmetrical and asymmetrical coplanar waveguides     

Effects of the doping profile on current characteristics in BSITs

Proposed are two doping profiles of the conducting channel in bipolar-mode static induction transistors (BSITs) that improve the current handling capability. By using the results obtained from two-dimensional device simulations, it is shown that BSITs with the proposed profiles exhibit higher drain current density and DC current gain than conventional BSITs. Also discussed is the tradeoff between the current and voltage capabilities     

Characterization of MIS structure coplanar transmission lines forinvestigation of signal propagation in integrated circuits

A full-wave analysis of metal-insulator-semiconductor (MIS) structure micron coplanar transmission lines on doped semiconductor substrates is carried out using a finite-difference time-domain approach. Metal conductor loss is taken into account in the analysis. Line parameters and electromagnetic field distributions are calculated over a wide frequency range involving slow-wave and dielectric quasi-transverse-electromagnetic mode limits. Measurements of these line parameters, varying substrate resistivity from 1 to 1000 Ω-cm, in the frequency range up to 40 GHz are also presented, and these agree with the analysis quite well. On the basis of these results, an equivalent circuit line model is induced and some considerations on the relationship between line structure and properties made     

Ideal FET doping profile

Using variational calculus it is possible to show, for each MOSFET voltage and device topology, that there exists an ideal drain region doping profile which yields the optimum resistance versus breakdown voltage tradeoff. Because of the inclusion, in the resistance, of the effects of spreading resistance this profile tends to have a higher doping concentration (lower resistivity) at the blocking junction, this point being at or near the point of maximum spreading resistance, a minimum in doping partway into the drain and then asymptotically approach a(1 - X/W)^{-1/2}form as derived by Hu [1] at the edge of the depletion layer. The theory and calculations in this paper compare the Hu profile, a constant profile and our optimum profile for various practical geometries over a range of breakdown voltages. It is shown that the higher the device voltage and the less important the spreading resistance effects, the closer the ideal profile approaches that of Hu. The ideal profile concept applies equally well to other FET or majority carrier (resistive) devices.     

I—V characteristics of GaAs MESFET with nonuniform doping profile

A simple analytical model of a GaAs MESFET with non-uniform doping is proposed. The analysis shows that at gate voltages well above the threshold (0.2-0.4 V) for a typical device the current saturation is related to the velocity saturation (with a possibility of a stationary domain formation at drain-to-source voltages high enough). Closer to the threshold the saturation is due to the channel pinchoff. In both regimes the nonuniformity of the doping profile may be essential. Another factor taken into consideration is the source series resistance which includes the contact resistance and the resistance of the gate-to-source region of the device. The calculated dependences of the transconductance and drain current on the gate voltage are in good agreement with the experimental results obtained by Eden, Zucca, Long, and others [1].     

Propagation and coupling characteristics of microstrip lines withlaminated ground plane

In this paper, we analyze the effect of laminated ground plane on the propagation and coupling characteristics of microstrip lines. Each lamina is modeled as an anisotropic layer, and transition matrix is used to relate the tangential field components in different laminae. An integral equation is formulated in the spectral domain, and the Galerkin's method is applied to solve the integral equation for the phase and the attenuation constants of several microstrip line structures. The effects of substrate dielectric are also studied. The attenuation constant variation thus obtained will be useful in circuit board design and in studying signal transmission in lamina environment     

Propagation characteristics of microstrip transmission line on ananisotropic material ridge

A microstrip transmission line residing on an electrically anisotropic material ridge embedded in a multilayered environment is studied using a coupled set of integral equations (IE's). The full-wave IE formulation easily accommodates arbitrary material anisotropy and inhomogeneity in the finite ridge region using equivalent polarization currents residing in a multilayered isotropic background. New results are presented for uniaxially anisotropic ridge structures which show that the transmission line propagation constant is sensitive to anisotropy for certain ridge structures and insensitive for others, compared to the conventional line on an infinite substrate. Results are also presented for a transmission line printed on a nonreciprocal solid-state magnetoplasma ridge. The current distribution associated with the dominant microstrip mode is investigated, where it is found that the transverse component of current is much larger for the ridge geometry than for the infinite substrate case, although the transverse component is still small compared to the longitudinal component     

传输线中脉冲信号传输特性的联合时频分析

用联合时频分析方法将一维时域或频域脉冲信号扩展到时间 -频率的二维平面 ,通过时间窗、频率窗和 Wigner- Ville分布的时频平面对矩形和高斯脉冲信号在传输线 (双导线和同轴线 )中的传输瞬态特性进行比较分析对比。联合时频分析可以更直观、更全面地了解脉冲信号在传输线任意时间和任意位置的瞬态变化。     

Propagation characteristics of partially loaded two-conductor transmission line for broadband light modulators

The characteristics of two-conductor transmission lines containing two dielectrics are derived. The results are applied to broad-band traveling-wave light modulators.     

Graphic method of substrate doping determination from C–V characteristics of MIS capacitors

A simple graphical method is presented which determines of the Fermi potential (substrate doping) from the high-frequency C–V characteristic of the MIS capacitor. This method is of general application and can be used for the study of any dielectric-semiconductor system at various ambient temperatures.     

Fast simulation of lossy transmission lines by the modified methodof characteristics

A set of recursive formulations based on the method of characteristics (MC) are derived to simulate lossy transmission lines in VLSI and multichip modules (MCMs) design     

The accuracy of reconstructing the semiconductor doping profile from capacitance-voltage characteristics measured during electrochemical etching

The accuracy of a number of techniques for the reconstruction of doping profiles on the basis of the capacitance-voltage measurements in an electrochemical cell are numerically analyzed. The two previous simple methods proposed by us are shown not only to allow the direct determination of the doping profile at the surface but also to be potentially more accurate than the conventionally used procedure. However, our calculation techniques require experimental data of a higher accuracy. In particular, the relative error of measurements should be within 5×10^?4, which is an order of magnitude smaller than the commonly available values.     

Reconstruction of the potential profile in an insulating layer using current-voltage characteristics of tunneling MIS diodes

A method for reconstruction of the potential profile in an insulating layer is developed on the basis of the field dependence of the tunneling current through the layer. The coordinates of the turning points as functions of the voltage applied to the insulating layer are determined in quasi-classical approximation from the tunneling current-voltage characteristics. The potential is constructed using these functions. The developed algorithm was applied to an n ⁺-Si-SiO₂-n-Si structure with oxide thickness of 37 Å. Typically, for a real potential profile, there exist relatively thick layers (of ～10 Å) with lowered potential that separate SiO₂ from the actual tunneling barrier.     

Two-dimensional doping profile characterization of MOSFETs byinverse modeling using I-V characteristics in the subthreshold region

In this paper, we present a new technique for the characterization of two-dimensional (2-D) doping profiles in deep submicron MOSFETs using current-voltage (I-V) characteristics in the subthreshold region. The main advantages of the technique are as follows. (1) It is capable of extracting 2-D doping profile (including channel-length) of deep submicron devices because of its immunity to parasitic resistance, capacitance, noise, and fringing electric fields. (2) It does not require any special test structures since only subthreshold I-V data are used. (3) It is nondestructive. (4) It has very little dependence on mobility and mobility models. (5) It is easy to use since data collection and preparation are straightforward. (6) It can be extended to the accurate calibration of mobility and mobility models using I-V characteristics at high current levels, because errors associated with uncertainties in doping profiles are removed     

Metal-insulator-semiconductor transmission lines

This paper investigates the one-dimensional metal-insulator-semiconductor transmission line. It develops closed-form expressions for equivalent-circuit parameters, compares them to exact calculations, and explores their limitations. It also investigates the usual assumption of single-mode propagation and shows that, in certain fairly common circumstances, the fundamental mode of propagation becomes so lossy that it can no longer be considered to be the dominant propagating mode