Journal ArticleDOI
A theory of transistor cutoff frequency (f T ) falloff at high current densities
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In this paper, it was shown that the observed falloff in the f T of a transistor at high currents is due to the spreading of the neutral base layer into the collector region of the device at high current densities.Abstract:
It is shown that the observed falloff in the f T of a transistor at high currents is due to the spreading of the neutral base layer into the collector region of the device at high current densities. The base layer spreading mechanism derives from an analysis of the effect of the current-dependent buildup of the mobile-carrier space-charge density in the collector transition layer. 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. The over-all effect of taking the mobile space charge into account in analyzing the collector transition region is that, at high current densities, the transition region boundary adjacent to the neutral base layer is displaced toward the collector metal contact with increasing collector current. The attendant widening of the neutral base layer results in the observed, high-current falloff in f T . The application of this theory to transistor structures of both the alloy and mesa variety yields, in each case, calculated curves of f T vs I c which are in reasonably good agreement with experiment.read more
Citations
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Journal ArticleDOI
A simple regional analysis of transit times in bipolar transistors
TL;DR: In this paper, the authors propose a quasi-static approach to calculate the cutoff frequency or unity gain bandwidth of a one-dimensional bipolar transistor by means of a numerical device simulation program, where the total transit time from emitter contact to collector contact is subdivided into five physically meaningful components.
Journal ArticleDOI
Foundation of rf CMOS and SiGe BiCMOS technologies
J. Dunn,David C. Ahlgren,Douglas D. Coolbaugh,Natalie B. Feilchenfeld,Gregory G. Freeman,David R. Greenberg,Robert A. Groves,Fernando Guarin,Y. Hammad,Alvin J. Joseph,Louis D. Lanzerotti,S. St Onge,Bradley A. Orner,Jae-Sung Rieh,Kenneth J. Stein,Steven H. Voldman,Ping-Chuan Wang,Michael J. Zierak,S. Subbanna,David L. Harame,D. A. Herman,Bernard S. Meyerson +21 more
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Journal ArticleDOI
A new effect at high currents in heterostructure bipolar transistors
TL;DR: In this article, large current densities in heterostructure bipolar transistors with heterostructured collectors are shown to cause an excess electron barrier leading to an increase in minority-carrier charge storage in the base and a decrease in current gain of the device.
Journal ArticleDOI
Two-dimensional carrier flow in a transistor structure under nonisothermal conditions
S.P. Gaur,D.H. Navon +1 more
TL;DR: In this article, a two-dimensional mathematical model is developed to predict the internal behavior of power transistors operating under steady-state conditions, which includes the internal self-heating effects in the transistors and is applicable to predict transistor behavior under high current and high-voltage operating conditions.
Journal ArticleDOI
Accurate analytical delay expressions for ECL and CML circuits and their applications to optimizing high-speed bipolar circuits
TL;DR: In this article, a linearity study of the propagation delay of bipolar circuits carried out using a SPICE program is discussed, and therefore analytical propagation delay expressions for ECL and CML circuits are derived using a sensitivity analysis.
References
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Journal ArticleDOI
The theory of p-n junctions in semiconductors and p-n junction transistors
TL;DR: The theory of potential distribution and rectification for p-n junctions is developed with emphasis on germanium, resulting in an admittance for a simple case varying as (1 + iωτ p )1/2 where τ p is the lifetime of a hole in the n-region.
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Mobility of Holes and Electrons in High Electric Fields
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The Dependence of Transistor Parameters on the Distribution of Base Layer Resistivity
J. L. Moll,I. M. Ross +1 more
TL;DR: In this article, a method of analyzing transistor behavior for any base-layer impurity distribution is presented, in particular expressions for emitter efficiency, transverse sheet resistance R, transit time, and frequency cut-off f?.
Journal ArticleDOI
Structure-Determined Gain-Band Product of Junction Triode Transistors
TL;DR: In this article, the authors compared the power gain of the junction triode with those of the field effect transistor and the analog transistor and showed that the gain-band product is nearly independent of the particular alpha cutoff frequency selected.