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Analytical modelling of the channel-charge in ion-implanted MOSFETs and MESFETs
Published in SPIE
1992
Volume: 1523
   
Pages: 278 - 285
Abstract
Analytical modelling of implanted Buried Channel (BC) and Surface Channel (SC) iMOSFETs and MESFETs is difficult since the highly nonuniform channel doping profile can not be integrated analytically to obtain the charge-voltage characteristics of the channel depletion layer. The present paper derives a general approximation to the non-uniform profile which gives simple and accurate closed form expressions directly in terms of device parameters for the various characteristics of all the FETs under all implant and bias conditions (the implant may be shallow, deep or multiple, and it may be partially or fully depleted depending upon the bias conditions). The derivation does not make any a-priori assumptions about the shape of the approximate profile. Instead, the shape emerges from a new formulation of the analytical modelling problem. It is shown that the necessary condition for analytical modelling of all the three FETs is the same, namely, expressing the depletion layer voltage drop V, as a polynomial of the depletion charge Qd, where the degree of the polynomial can not exceed two. Next it is demonstrated that such a polynomial for the Vd-Qd characteristics of implanted FETs can be obtained by approximating the doping profile by a "Shifted-rectangle" profile whose parameters can be derived directly from implantation parameters. © 1992 SPIE. All rights reserved.
About the journal
JournalData powered by TypesetProceedings of SPIE - The International Society for Optical Engineering
PublisherData powered by TypesetSPIE
ISSN0277786X
Open AccessNo
Concepts (14)
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    Bias voltage
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    Integrated circuits
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    Mesfet devices
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    Polynomials
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    Semiconductor doping
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    Buried channels
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    Channel depletion
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    Closed-form expression
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    Device parameters
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    DOPING PROFILES
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    IMPLANTATION PARAMETERS
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    NONUNIFORM CHANNELS
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    SURFACE CHANNEL
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    Analytical models