A universal electron mobility model of strained Si MOSFETs based on variational wave functions

Institute of Microelectronics, Tsinghua University, Beijing 100084, People’s Republic of China
Solid-State Electronics (Impact Factor: 1.51). 06/2008; 52(6):863-870. DOI: 10.1016/j.sse.2008.01.007

ABSTRACT A new model is proposed to describe the electron mobility enhancement in strained Si MOSFETs inversion layers using the variational wave functions in the triangular potential approximation. Phonon scattering and surface roughness scattering are included in this model and electron mobility enhancements due to the suppression of these two scatterings are accounted for, respectively. A process-dependent interface parameter is introduced to fit with various technologies. Results from the model show good agreement with experiments for different Ge mole fractions and for a wide range of vertical effective field and temperature. The model is very interesting for implementation in conventional device simulators.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Photoluminescence spectroscopy is applied on tensely strained silicon on insulator layer in order to evaluate the temperature dependence of the indirect energy bandgap. The strained silicon indirect bandgap follows a similar behaviour to bulk silicon at high temperature (from 80 K up to 300 K) which was described from the Varshni [Physica 34, 149 (1967)] and Bose-Einstein equations. Nevertheless, at low temperature (from 9 K to 80 K), an unusual blueshift of the bandgap is evidenced. The latter can be modelled considering band-tail states of density of states which are related to the strain fluctuation.
    Applied Physics Letters 03/2012; 100(10). DOI:10.1063/1.3691955 · 3.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we address a physics based closed form model for the energy band gap (E-g) and the transport electron effective mass in relaxed and strained [100] and [110] oriented rectangular Silicon Nanowire (SiNW). Our proposed analytical model along [100] and [110] directions are based on the k.p formalism of the conduction band energy dispersion relation through an appropriate rotation of the Hamiltonian of the electrons in the bulk crystal along [001] direction followed by the inclusion of a 4 x 4 Luttinger Hamiltonian for the description of the valance band structure. Using this, we demonstrate the variation in Eg and the transport electron effective mass as function of the cross-sectional dimensions in a relaxed [100] and [110] oriented SiNW. The behaviour of these two parameters in [100] oriented SiNW has further been studied with the inclusion of a uniaxial strain along the transport direction and a biaxial strain, which is assumed to be decomposed from a hydrostatic deformation along [001] with the former one. In addition, the energy band gap and the effective mass of a strained [110] oriented SiNW has also been formulated. Using this, we compare our analytical model with that of the extracted data using the nearest neighbour empirical tight binding sp(3)d(5)s* method based simulations and has been found to agree well over a wide range of device dimensions and applied strain.
    Solid-State Electronics 02/2013; 80:124-134. DOI:10.1016/j.sse.2012.11.001 · 1.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The current–voltage characteristics and the carrier-transport mechanism of the Er–silicide (ErSi1.7) Schottky contacts to strained-silicon-on-insulator (sSOI) and silicon-on-insulator (SOI) were investigated. Barrier heights of 0.74 eV and 0.82 eV were obtained for the sSOI and SOI structures, respectively. The barrier height of the sSOI structure was observed to be lower than that of the SOI structure despite the formation of a Schottky contact using the same metal silicide. The sSOI structure exhibited better rectification and higher current level than the SOI structure, which could be associated with a reduction in the band gap of Si caused by strain. The generation–recombination mechanism was found to be dominant in the forward bias for both structures. Carrier generation along with the Poole–Frenkel mechanism dominated the reverse-biased current in the SOI structure. The saturation tendency of the reverse leakage current in the sSOI structure could be attributed to strain-induced defects at the interface in non-lattice-matched structures.
    Journal of Nanoscience and Nanotechnology 11/2014; 14(11). DOI:10.1166/jnn.2014.9893 · 1.34 Impact Factor