Scattering in Nano-Electronic Devices

Third generation ultra scaled high-performance MOSFETs are based on High-x Metal gate (HkMG) technology. A new theoretical model for non-ideal metal gate in conjunction with high-x' stack is developed to predict inversion channel mobility. Impact of surface phonons (originating from high-a- dielectric) on mobility degradation is evaluated using the model, incorporating newly proposed criteria for determining Landau damping regimes. Phonon-electron interaction- the most dominant scattering mechanism at room and higher temperatures is also studied. It is concluded that the well known trend for phonon limited mobility, observed in measurements, is not observed in the range where surface roughness scattering is negligible, through the existing transport models. A new scheme is proposed in which the scattering phonon deformation potentials are channel density dependent. Empirical fitted parameters successfully reproduce the reported trend and the mobility magnitude fairly matches with the experimental data. Another prominent scattering mechanism responsible for mobility degradation under strong bias is due to roughness at insulator/substrate interface. The source term responsible for the strongest impact on SR mobility is derived on physical grounds. Universal mobility of a conventional MOSEET is achieved using the phonon and the comprehensive SR model. Closely related to “normal” SR scattering is the “remote" scattering of carriers at gate/insulator interface. Remote surface scattering (RSR) is significant in ultra-thin MOS structures. The existing RSR model presented by Gamiz et al is modified. It is shown that this modification to the model is necessary in order to observe the full impact of rms height of the amplitude of the roughness. In summary, except for the low field regime, dominated by Coulomb scattering models have been demonstrated capable of predicting high-field mobility, which is the technologically relevant mobility, in metal gate high-a- dielectric ultra-thin MOSEETs using a quantum mechanical description of the quantization of the inversion layer.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

2008

Author dc:creator

• Shah, Raheel

Advisor dc:contributor.advisor

• Raheel

Licence

• https://dora.dmu.ac.uk/bitstreams/253edd90-bdab-4675-af02-ae2323410ee4/download