Analysis of hot-carrier degradation in a SOI LDMOS transistor with a steep retrograde drift doping profile

This paper reports the electrical performances of a RF SOI power LDMOS transistor with a retrograde doping profile in the entire drift region. A comparison between retrograde and conventional uniformly doped drift SOI power LDMOS transistors is provide by means of a numerical simulation analysis. The proposed structures exhibit better performances in terms of trapped electron distribution and transconductance degradation with no modification of the breakdown voltage capability. Simulation results show that, at a given bias conditions, the reduction of lateral electric field peak at the silicon surface due to the implementation of the retrograde doping profile accounts for the observed reduction of the hot carrier degradation effect.     

Small-signal impedance of bulk semiconductor amplifier having a nonuniform doping profile

A convenient method for studying the small-signal impedance of a bulk semiconductor amplifier having a nonuniform doping profile is presented. The small-signal impedance is represented as a two-dimensional sum of the interaction impedance which represents the electrical interaction between various sections in the amplifier due to the transport effect. When the diffusion current is negligible, the two-dimensional plot of the magnitude of the interaction impedance shows which part of it is important. The two-dimensional representation may provide a convenient method of synthesizing the doping profile of a bulk semiconductor amplifier which gives a desired impedance characteristic.     

The influence of a doping profile on the characteristics of an ion-implanted GaAs field-effect transistor with a Schottky barrier

A GaAs field-effect ion-implanted transistor with a Schottky barrier is simulated. The doping profile obtained when doping through an insulator mask is determined and the dependences of the static transistor characteristics on the parameters of the doping profile are calculated and analyzed. The physical processes controlling the transistor characteristics in the case of a variation in the parameters of its doping profile and the coefficient of compensation of the substrate are studied. Based on calculations, the optimal doping-profile parameters ensuring the best characteristics for transistors are predicted.     

A technique for directly plotting the inverse doping profile of semiconductor wafers

A new technique for plotting doping profiles of semiconductor wafers is described. This technique involves driving a Schottky diode deposited on the surface with a small constant RF current (a few hundred microamperes at 5 MHz). The depth of the depletion layer is varied by changing the dc bias, but this is the only role of the dc voltage. The inverse doping profile n^-1(x) is obtained by monitoring the voltage across the diode at the fundamental frequency, which is proportional to the depth x, and the second harmonic voltage, which is proportional to n^-1. This type of plotter has the advantages of simplicity, high resolution (limited only by the Debye length in most cases), immediate results, and economy.     

The Feasibility of creating a high-speed semiconductor—semimetal—semiconductor transistor

The feasibility of creating a semiconductor-semimetal-semiconductor transistor with fast electron transit through its base is considered. Deceased.     

Partitioned-charge-based BJT model using transient charge controlrelations for arbitrary doping and bias conditions

Recent transient charge control (TCC) relations such as the TICC or more general GTCC are applied to accurate calculation of base charge partitioning for arbitrary doping profiles and bias conditions. A large-signal BJT circuit model is developed using this approach; both DC and complete first-order AC characteristics are derived from static device simulations     

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.     

A new double gate SOI LDMOS with a step doping profile in the drift region

uences of device parameters on BV and Ron, sp are investigated by simulation. The results indicate that BV is increased by 35.2% and Ron, sp is decreased by 35.1% compared to a conventional SOILDMOS.     

漂移区阶梯掺杂的双栅SOI LDMOS研究

A new double gate SOI LDMOS with a step doping profile in the drift region is proposed. The structure is characterized by one surface gate and another embedded gate under the P-body region. The broadened current flow path and the majority carrier accumulation layer on the side wall of the embedded gate reduce the specific on-resistance （Ron, sp）. The electric field distribution is improved due to the embedded gate and step doping profile, resulting in a high breakdown voltage （BV） and low Ron, sp. The influences of device parameters on BV and Ron, sp are investigated by simulation. The results indicate that BV is increased by 35.2% and Ron, sp is decreased by 35.1% compared to a conventional SOI LDMOS.     

Exact equivalent circuit model for steady-state characterization of semiconductor devices with multiple-energy-level recombination centers

One-dimensional steady-state characteristics of a two-terminal semiconductor device is modeled by an exact transmission-line circuit model, This is generalized to include Shockley-Read-Hall (SRH) recombination centers with an arbitrary number of energy levels. It is then applied to a study of the double-acceptor zinc centers in silicon p-n junction diodes. The exact internal characteristics of the diodes; such as the spatial variation of carrier densities, electric field, net charge density, recombination rate, and current densities; are obtained numerically from the circuit model and studied at different injection levels. The zinc population and the relative importance of recombination at each of the two zinc energy levels is interpreted by the Sah-Shockley theory for multiple-energy-level SRH centers.     

Thermalelectro-feedback model for multi-emitter finger power heterojunction bipolar transistor. Part I: Temperature profile

Poor thermal conductivity of GaAs, a self-heating phenomenon which results in the rapid rise of device temperature, is the major factor that limits and even degrades the electrical performance of GaAs-based heterojunction bipolar transistor (HBT) operated at high power densities. On the basis of this consideration, a numerical model is presented to study the interaction mechanism between the thermal and electrical behavior of AlGaAs/GaAs HBT with multiple-emitter fingers. The model mainly comprises a numerical model applicable for multi-finger HBT that solves the three-dimensional heat transfer equation. The device design parameters that influence the temperature profile and current distribution of the device are identified, and optimization concerning the device performance is made.     

A nonlinear lumped network model of semiconductor devices with consideration of recombination kinetics

A nonlinear lumped network model of semiconductor devices with consideration of recombination kinetics is developed. A distributed system, based on a set of recombination kinetic equations for the multiple energy level centers, in addition to continuity, current flow relationships, and Poisson's equation, is shown to be approximated by a lumped RC network. As an example of application, the forward characteristics of a gold-doped silicon diode are calculated. The calculated results are found to be in good agreement with the experimental results within the range where the recombination current through gold centers is dominant.     

The influence of heavy doping on the emitter efficiency of a bipolar transistor

The emitter efficiency current gain βγis calculated taking into account the effect of the bandgap decrease caused by heavy doping of the emitter. It is found that this effect reduces the emitter efficiency and explains experimental results on the temperature dependence of the current gain. It also predicts an optimum emitter doping for a given base doping.     

Effects of lateral mode and carrier density profile on dynamic behaviors of semiconductor lasers

Dynamic behaviors of the semiconductor lasers have been investigated both theoretically and experimentally. A single-mode rate equation, which takes account of the lateral mode profile and the carrier density profile, has been solved numerically. Effects of the carrier and lateral mode confinement have been clarified. The lateral mode deformation in lasers without a built-in mode confinement structure greatly enhances the relaxation oscillations. In lasers whose stripe width is narrower thansim10 mum, the carrier diffusion is found to play an important role in suppressing the relaxation oscillations, especially for lasers without a lateral carrier confinement structure. On the other hand, the fraction of the spontaneous emission going into the lasing mode is significant for lasers with a lateral carrier confinement structure. The slow increase of the laser output at the transient is confirmed to be due to the carrier diffusion.     

A technique for directly plotting the doping profile of semiconductor wafers (“8-shaped way”)

A new technique for directly plotting the doping profile of a semiconductor wafer is described. The peculiarities of this technique are a double passing (with a frequency conversion) of a test signal through the sample and the use of an autoregulated voltage source. The present technique has certain advantages as compared with previous ones especially for small measured capacitances (1 pF or less). Both “high frequency” and “low frequency” N(x) values may be obtained by using this technique.     

Characteristics of a semiconductor laser coupled with a fiber Bragg grating with arbitrary amount of feedback

Stationary characteristics (such as laser frequency at threshold, light-intensity curve, etc.) and relative intensity noise of laser diodes coupled with an external Bragg reflector are studied for arbitrary amount of optical feedback. We put the stress on the interplay between external and internal cavities when the feedback strength is increased. For strong feedback, new stationary solutions that do not exist in the case of conventional feedback appear, while the ellipse, which usually contains the modes and so-called antimodes, collapse in the plane frequency-gain. Finally, analytical expressions are compared with numerical results obtained through a new approach that uses Green functions.     

The influence of lateral carrier diffusion and surface recombination on the behavior of semiconductor optical amplifier (SOA)-based MMIs

The influence of lateral carrier diffusion and surface recombination on the self-imaging properties of semiconductor-optical-amplifier-based multimode interference couplers has been verified by simulations using a beam propagation method. It shows a significant degradation of the self-imaging properties of these devices. Buried heterostructures or deeply etched waveguide structures can decrease the impact when the degree of surface recombination is sufficiently low.     

Lateral nonuniform doping technique and its application to the fabrication of GaAs MESFETs with a lateral linear doping channel

A novel lateral nonuniform doping technique, which is compatible with conventional ion implantation technology, is reported. GaAs MESFETs with a linear lateral doping channel have been fabricated and improvements in performance have been demonstrated.<>