Physical limitations and device modeling -- References. Excellent agreement between measurements and compact model simulation is shown. Electric field in the collector region. The coherence reveals a frequency dependence at lower bias due to the presence of dominant generation-recombination mechanisms, whereas at higher bias, the coherence approaches unity. In this paper a comparative analysis of compact noise model formulations for intrinsic bipolar transistors is presented.
Abstract: Suitable for professionals from the process development, modeling and circuit design community who are interested in the application of bipolar transistors, this book offers an overview on different device designs of modern bipolar transistors, along with their operating conditions. The models are verified using measurement data and circuit simulation. It is shown that a considerable improvement can be obtained when the concept is extended by allowing time delays in the relations between controlling charges and terminal voltages and currents. Depletion junction charges and capacitances. Repercussions of working in the avalanche regime on some important transistor properties like unilateral and maximum available power gain, as well as on the stability factor are presented, demonstrated by measurements on modern industrial devices and analysed by corresponding simulations using the physics-based world standard compact model for bipolar transistors, Mextram. The bias dependence of the coherence is studied in several transistor geometries. There exist several problems where only a frequency-domain characteristic is given, for instance the description of the terminal behaviour by frequency-dependent parameters, and where we are only interested in the results of a small-signal frequency-domain analysis.
Modeling of the transit time, the base resistance, and the emitter junction capacitance was improved. A brief history on bipolar transistor technology. In this paper, we develop a correlated noise model for bipolar transistors from an accurate nonquasi-static model. The validity of the assumptions has been checked by exact numerical device simulation. Thus the contribution of the minority charges can still be determined experimentally by measuring τ f I C.
The increased range of validity of the extended charge-control model is demonstrated in detail, by confronting it with a rigorous model and comparing small-signal parameters. The first section describes the model topology and sets the implemented equations that allow to take into account of the physical phenomena. Analytical models for base-emitter tunneling current and base-collector breakdown weak avalanche are presented. The corresponding equations are implemented into a compact model. Zur Bestimmung der Modellparameter wird ein Verfahren vorgestellt, das einfach und zuverlässig physikalisch sinnvolle Parameterwerte liefert.
A technology-independent, inherently nonlinear approach is proposed for the compact modelling of high-frequency noise in microwave transistors under large-signal operating conditions. A low-cost, high-performance vector network analyzer approach for pulsed operation is presented. The attendant widening of the neutral base layer results in the observed, high-current falloff in f T. The model also integrates scaling rules function of emitter length W and number of fingers N. Comparison to device simulation results show good agreement. For the noise calculations the transistor can be treated as a linear ergodic system, described by a two-port.
The relationship between spectral densities and mean-square fluctuations is given and the noise factor of the linear twoport is expressed in terms of the mean-square fluctuations of the source current and the internal noise sources. The equivalent circuit for each region is separately derived using the transmission line equation with reasonable approximations. The book begins with an overview on the different device designs of modern bipolar transistors, along with their relevant operating conditions; while the subsequent chapter on transistor theory is subdivided into a review of mostly classical theories, brought into context with modern technology, and a chapter on advanced theory that is required for understanding modern device designs. The overall purpose of this paper including Part I, in this issue is the prediction of the ultimate electrical high-frequency performance potential for SiGeC heterojunction bi-polar transistors under the constraints of practical applications. This book aims to provide a solid basis for the understanding of modern compact models.
An excellent agreement is obtained between the measured and simulated S-parameters. A model applicable to any compact models is derived and implemented using Verilog-A. The book provides an overview, characteristics, and derivative applications for each device covered. A further simplified version that uses only one extra node is found to be identical with a state-of-the-art correlated noise model. The imaginary part of optimum generator admittance is slightly worse than without this effect.
The weak avalanche regime is the regime where carriers generated in a process of impact ionization do not generate extra carriers. It may be seen fromFigure 2 that the three models fail to follow the exponential behavior of Ce and begin to increase at higher bias voltages. Therefore, in this paper the contribution of the p- substrate and channel stopper to the equivalent circuits of Si-bipolar transistors and bond pads are theoretically and experimentally investigated up to very high frequencies. A large variety of spectral densities for the noise models can be found in the litera- ture. We analysed three devices having different Ge content 10%-20%, 10%-25% and 10%-30%. Following the theoretical results, model formulations suitable for implementation in the large-signal domain are developed.
The propagation of the internal distributed noise sources up to the intrinsic device terminals leads to a set of non-stationary, correlated equivalent noise generators, nonlinearly controlled by the instantaneous large-signal working point of the device. Based on different geometries of bipolar transistors, a new scalable method to determine the parasitic capacitances is presented. The correla- tion between the mobile base charge i. Calculations show that at sufficiently high collector current levels, the mobile space-charge density in the collector transition layer cannot be considered negligible in comparison to the fixed charge density of that region. After the rational function fitting to related admittance parameters, a number of coefficients are accurately obtained and then all the model parameters are directly extracted without any special test structure or numerical optimization. This goal is achieved by utilizing most advanced device simulation tools with parameters calibrated to existing experimental results. Exploration of the impact of intrinsic base doping profiles on noise performance demonstrates the potential for device optimization.
Through the use of a new charge control relation linking junction voltages, collector current, and base charge, the model includes high injection effects. To make the model suitable for circuit simulators, all current and charge formulations are continuously differentiable , giving at least continuous first-order derivatives i. Finally, the simulator was successfully applied to investigate noise coupling via the substrate The design and optimization of high-speed integrated bipolar circuits requires accurate and physical transistor models. In contrast to homo-junction transistors, the increase of the collector transit time is negligible and even the saturation value very small. Both modes, as well as the transition from one to the other are investigated by a physical description.