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
Estimation of Collector Current Spreading in InGaAs SHBT Having 75-nm-Thick Collector
TL;DR: In this paper, the authors investigated collector current spreading in InGaAs single heterojunction bipolar transistors (SHBTs) having a collector thickness of 75nm and three different emitter widths (200, 400, and 600nm) and the highest cutoff frequency that was obtained was 468GHz.
Dissertation
Displacement Damage and Ionization Effects in Advanced Silicon-Germanium Heterojunction Bipolar Transistors
Journal ArticleDOI
The influence of high current densities on the avalanche breakdown characteristics of bipolar transistors
V. A. Browne,P. Mars +1 more
TL;DR: In this article, the effects of large current densities upon the common emitter breakdown characteristics of both epitaxial and alloyed junction transistors, although the arguments may be equally applied to devices fabricated by other techniques, are investigated.
Proceedings ArticleDOI
The Effects of Structural Parameters Alteration on Improvement of Current Gain and High Frequency Performance of a AlGaAs/GaAs SHBT
TL;DR: In this article, the influence of structural parameters variations on the current gain and high frequency performance of a AlGaAs/GaAs HBT was investigated and analytical equations were used to predict conventional microwave-photonic device structure for performance improvement.
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.
Journal ArticleDOI
Mobility of Holes and Electrons in High Electric Fields
TL;DR: In this paper, the field dependence of mobility has been determined for electrons and holes in both germanium and silicon, and the observed critical field at 298\ifmmode^\circ\else\textdegree\fi{}K beyond which $\ensuremath{\mu}$ varies as ${E}^{-}\frac{1}{2}}$.
Journal ArticleDOI
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.