Temperature dependence of generation-recombination noise in p−n{p{-}n} junctions

Fundamental aspects of the $p{-}n$ junction have been considered in order to obtain an analytical model for generation-recombination (g-r) current noise. Considering neutrality and fixed-bias voltage conditions a fluctuation in the charge trapped in deep levels is related to fluctuations of the charge density and the electric field at the borders of the space-charge region. These variations are then converted to current fluctuations making use of a collective transport noise theory. Generation-recombination current noise in $p{-}n$ junctions is analyzed at low and high temperatures for different bias conditions.

Capture Process by Shallow Donors in Silicon at Low Temperatures

Thermal capture by shallow attractive impurities has been studied by the Monte Carlo method at low temperatures. In order to model this process, the perturbation produced by the highest excited impurity states associated to the ideal Coulombic potential and the multiphonon mechanism were combined in the same simulation procedure. These excited states are considered to produce an energy quasicontinuum or impurity band where the carrier can move assisted by lattice phonons. To characterize the ground-state capture, the transition rates of multiphonon transitions from the impurity band and from the conduction band have been included. Electron capture cross sections have been calculated as a function of the temperature and compared with experimental data from the P+, As+ and Sb+ shallow donors in Si, achieving a good fitting with the Huang-Rhys factor, S, as the only free parameter

Section de capture des trous sur le niveau Ev + 0,34 eV de Si : Pt

From capacitance measurements, the thermal capture cross-section of free holes at the platinium centre located at Ev + 0.34 eV is determined through the time dependence of the net ionized charges. In the temperature range [77 K, 120 K] the result is $$.La section efficace de capture thermique des trous sur le centre à Ev + 0,34 eV associé au platine dans le silicium est déduite de la dépendance temporelle de la densité des centres profonds ionisés, mesurée par technique capacitive. Pour le domaine de température [77 K, 120 K], le résultat est$$

Strained Si/SiGe Heterostructures at Low Temperatures. A Monte Carlo Study

Monte Carlo simulations are used to study the transport properties of electrons in strained silicon inversion layers in Si/SiGe MOSFETs at low temperature. The strain produces an enhancement of electron mobility due to the reduction of intervalley scattering and a lower effective conduction mass as a consequence of the valley splitting. In this work, mobility curves for different Ge concentrations are obtained by Monte Carlo simulation at both low and room temperatures. It has been observed that at room temperature mobility enhancement saturates at a Ge concentration close to x=0.3, while the mole fraction of Ge at which the electron mobility curves saturate is much lower at low temperature. In addition, the relative enhancement at low temperatures is much less than at room temperature. Finally, mobility curves show a tendency to coincide at high transverse electric fields, regardless of the Ge concentration, as a consequence of the greater concentration of electrons in the ground subband