Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors

The base width of a Bipolar Junction Transistor in an integrated circuit is very small and recombination within the base can safely be neglected. In most of the works on Base Transit Time with reverse biased collector junction the expressions for transit time have been derived separately for high in...

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Main Author:	Khandoker, Ahsan Habib
Format:	Thesis
Published:	1999
Subjects:	TK Electrical engineering Electronics Nuclear engineering TK7800-8360 Electronics TK7871 Electronics > Materials
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spelling	my-mmu-ep.62015-06-23T08:46:32Z Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors 1999-06-14 Khandoker, Ahsan Habib TK Electrical engineering. Electronics Nuclear engineering TK7800-8360 Electronics TK7871 Electronics--Materials The base width of a Bipolar Junction Transistor in an integrated circuit is very small and recombination within the base can safely be neglected. In most of the works on Base Transit Time with reverse biased collector junction the expressions for transit time have been derived separately for high injection and low injection condition of operations. But in this work we have obtained a new analytical expression for Base Transit Time with reverse biased collector junction that can be applied for all levels of injections. The results obtained by using the new formulation are in good agreement with numerical results available in the literature. In the second part of this work, the Base Transit Time with collector junction forward biased is studied. When the collector junction is forward biased, the base is extended into the collector. Under this situation total transit time is the time taken by electron to traverse base and also the injection region of the collector. Recent works have shown that the collector minority carrier lifetime is finite. Therefore, recombination current in the collector minority carrier lifetime is finite. Therefore recombination current in the collector cannot be neglected. Considering drift and diffusion current and recombination, expressions for collector transit time with forward biased collector junction are obtained for quasi- and hard-saturation regions of operation. The results are compared with those obtained without recombination. The two results are deviated significantly from each other. The transit time is found strongly dependent upon collector minority carrier lifetime. When the effective surface recombination velocity is not infinite, the charge storage in collector is large and transit time increases with current. 1999-06 Thesis http://shdl.mmu.edu.my/6/ http://library.mmu.edu.my/diglib/onlinedb/dig_lib.php masters Multimedia University Faculty of Engineering
institution	Multimedia University
collection	MMU Institutional Repository
topic	TK Electrical engineering Electronics Nuclear engineering TK7800-8360 Electronics TK7871 Electronics--Materials
spellingShingle	TK Electrical engineering Electronics Nuclear engineering TK7800-8360 Electronics TK7871 Electronics--Materials Khandoker, Ahsan Habib Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors
description	The base width of a Bipolar Junction Transistor in an integrated circuit is very small and recombination within the base can safely be neglected. In most of the works on Base Transit Time with reverse biased collector junction the expressions for transit time have been derived separately for high injection and low injection condition of operations. But in this work we have obtained a new analytical expression for Base Transit Time with reverse biased collector junction that can be applied for all levels of injections. The results obtained by using the new formulation are in good agreement with numerical results available in the literature. In the second part of this work, the Base Transit Time with collector junction forward biased is studied. When the collector junction is forward biased, the base is extended into the collector. Under this situation total transit time is the time taken by electron to traverse base and also the injection region of the collector. Recent works have shown that the collector minority carrier lifetime is finite. Therefore, recombination current in the collector minority carrier lifetime is finite. Therefore recombination current in the collector cannot be neglected. Considering drift and diffusion current and recombination, expressions for collector transit time with forward biased collector junction are obtained for quasi- and hard-saturation regions of operation. The results are compared with those obtained without recombination. The two results are deviated significantly from each other. The transit time is found strongly dependent upon collector minority carrier lifetime. When the effective surface recombination velocity is not infinite, the charge storage in collector is large and transit time increases with current.
format	Thesis
qualification_level	Master's degree
author	Khandoker, Ahsan Habib
author_facet	Khandoker, Ahsan Habib
author_sort	Khandoker, Ahsan Habib
title	Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors
title_short	Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors
title_full	Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors
title_fullStr	Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors
title_full_unstemmed	Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors
title_sort	analytical expression for total base transit time in epitaxial bipolar transistors
granting_institution	Multimedia University
granting_department	Faculty of Engineering
publishDate	1999
_version_	1747829081222676480

Analytical expression for total Base Transit Time in Epitaxial Bipolar Transistors

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