A one dimensional study of the epitaxial NPN transistor
A one dimensional study of the epitaxial NPN transistor
Bipolar integrated circuit transistors are made on a thin and lightly doped epitaxial layer. This thesis is a study of the effect of this epitaxial layer on the characteristics of such NPN transistors. with particular emphasis on the inverse (i. e. upward) mode of operation. The effect of the epitaxial layer on normal (i. e. downward) operation is also considered theoretically, but with less emphasis. The basic theoretical assumptions that can be applied to the epitaxial region are first reviewed in detail and then used to develop a one dimensional theory for the NPN~N+ transistor. This analysis gives the D. C. terminal characteristics for both normal and inverse operation and also predicts the dependence of Ll, on collector current. It is found that for typical process parameters, the f.l. in inverse operation is proportional to 1/VIc over a wide current range. A cone rehensive test chip has been designed to test the theory. In addition to the basic devices under study, special test structures are included to provide independent determination of the basic deviceparameters. In order to determine the f.l. in upward operation, it was necessary to develop a new measuring technique, capable ofmeasuring fT at current levels down to IPA or less. Experimental results arc presented for devices fabricated on epitaxial layers of high resistivity and various thicknesses, and it is shown that there is good agreement with the theory. These results are directly applicable to the understanding of integrated injection logic circuits fabricated on high resistivity epitaxial layers.
University of Southampton
1982
Kwan, Kin-Wah
(1982)
A one dimensional study of the epitaxial NPN transistor.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Bipolar integrated circuit transistors are made on a thin and lightly doped epitaxial layer. This thesis is a study of the effect of this epitaxial layer on the characteristics of such NPN transistors. with particular emphasis on the inverse (i. e. upward) mode of operation. The effect of the epitaxial layer on normal (i. e. downward) operation is also considered theoretically, but with less emphasis. The basic theoretical assumptions that can be applied to the epitaxial region are first reviewed in detail and then used to develop a one dimensional theory for the NPN~N+ transistor. This analysis gives the D. C. terminal characteristics for both normal and inverse operation and also predicts the dependence of Ll, on collector current. It is found that for typical process parameters, the f.l. in inverse operation is proportional to 1/VIc over a wide current range. A cone rehensive test chip has been designed to test the theory. In addition to the basic devices under study, special test structures are included to provide independent determination of the basic deviceparameters. In order to determine the f.l. in upward operation, it was necessary to develop a new measuring technique, capable ofmeasuring fT at current levels down to IPA or less. Experimental results arc presented for devices fabricated on epitaxial layers of high resistivity and various thicknesses, and it is shown that there is good agreement with the theory. These results are directly applicable to the understanding of integrated injection logic circuits fabricated on high resistivity epitaxial layers.
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Published date: 1982
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Local EPrints ID: 459915
URI: http://eprints.soton.ac.uk/id/eprint/459915
PURE UUID: 5882d0a0-2452-4ac1-861c-a3de88d1fa27
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Date deposited: 04 Jul 2022 17:27
Last modified: 04 Jul 2022 17:27
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Author:
Kin-Wah Kwan
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