Theoretical Analysis of Transconductance Enhancement Caused by Electron-Concentration-Dependent Screening in Heavily Doped Systems

Shirun HO  Aya MORIYOSHI  Isao OHBU  Osamu KAGAYA  Hiroshi MIZUTA  Ken YAMAGUCHI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.2   pp.155-160
Publication Date: 1994/02/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on 1993 VLSI Process and Device Modeling Workshop (VPAD 93))
Category: Device Modeling
Keyword: 
transconductance,  mobility,  self-consistent and nonequilibrium screening,  heavily doped systems,  ionized impurity scattering,  

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Summary: 
A new mobility model dependent upon electron concentration is presented for studying the screening effect on ionized impurity scattering. By coupling this model with the drift-diffusion and Hartree models, the effects of self-consistent and quasi-equilibrium screening on carrier transport in heavily doped systems are revealed for first time. The transport mechanism is found to be dominated by the electron-concentration-dependent mobility, and transconductance is shown to be determined by effective mobility and changes from degraded to enhanced characteristics with electron concentration modulation.