Paper Title:
Modelling of the Anomalous Field-Effect Mobility Peak of O-Ta2Si/4H-SiC High-k MOSFETs Measured in Strong Inversion
  Abstract

A high field-effect mobility peak (50 cm2/Vs) has been extracted in (0001) Si face 4HSiC MOSFETs with oxidized Ta2Si (O-Ta2Si) high-k dielectric (k~20) as gate insulator, with their gates in the strong inversion regime. The interface state density (Dit) has not been particularly reduced in O-Ta2Si capacitors. This anomalous mobility enhancement is explained in terms of Coulomb scattering reduction and quantified using a physical model based on the Lombardi mobility model. The anomalous mobility increase is closely related to the leakage current, and also to the gate breakdown mechanism. We propose a model for which the observed interfacial SiO2 tunnel current combined with Poole-Frenkel mechanisms at the O-Ta2Si gate generates a sufficiently low abrupt transition in gate breakdown to obtain an effective passivation of the interface traps. Under these conditions, the increase of free carriers in the inversion layer induced by the gate leakage diminishes the effect of the interface trap Coulomb scattering.

  Info
Periodical
Materials Science Forum (Volumes 527-529)
Edited by
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
Pages
1059-1062
DOI
10.4028/www.scientific.net/MSF.527-529.1059
Citation
A. Pérez-Tomás, M. Vellvehi, N. Mestres, J. Millan, P. Vennegues, J. Stoemenos, "Modelling of the Anomalous Field-Effect Mobility Peak of O-Ta2Si/4H-SiC High-k MOSFETs Measured in Strong Inversion ", Materials Science Forum, Vols. 527-529, pp. 1059-1062, 2006
Online since
October 2006
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