Dielectric relaxation and Charge trapping characteristics study in Germanium based MOS devices with HfO2 /Dy2O3 gate stacks

In the present work we investigate the dielectric relaxation effects and charge trapping characteristics of HfO2 /Dy2O3 gate stacks grown on Ge substrates. The MOS devices have been subjected to constant voltage stress (CVS) conditions at accumulation and show relaxation effects in the whole range of applied stress voltages. Applied voltage polarities as well as thickness dependence of the relaxation effects have been investigated. Charge trapping is negligible at low stress fields while at higher fields (>4MV/cm) it becomes significant. In addition, we give experimental evidence that in tandem with the dielectric relaxation effect another mechanism- the so-called Maxwell-Wagner instability- is present and affects the transient current during the application of a CVS pulse. This instability is also found to be field dependent thus resulting in a trapped charge which is negative at low stress fields but changes to positive at higher fields.Comment: 27pages, 10 figures, 3 tables, regular journal contribution (accepted in IEEE TED, Vol.50, issue 10

On entropy, specific heat, susceptibility and Rushbrooke inequality in percolation

We investigate percolation, a probabilistic model for continuous phase transition (CPT), on square and weighted planar stochastic lattices. In its thermal counterpart, entropy is minimally low where order parameter (OP) is maximally high and vice versa. Besides, specific heat, OP and susceptibility exhibit power-law when approaching the critical point and the corresponding critical exponents $\alpha, \beta, \gamma$ respectably obey the Rushbrooke inequality (RI) $\alpha+2\beta+\gamma\geq 2$. Their analogues in percolation, however, remain elusive. We define entropy, specific heat and redefine susceptibility for percolation and show that they behave exactly in the same way as their thermal counterpart. We also show that RI holds for both the lattices albeit they belong to different universality classes.Comment: 5 pages, 3 captioned figures, to appear as a Rapid Communication in Physical Review E, 201

Multiphoton excitations in vibrational rotational states of diatomic molecules in intense electromagnetic field

A theory is presented and a calculational procedure is outlined for evaluating transition amplitudes of multiphoton excitations of vibrational-rotational levels in diatomic molecules. This theory can be utilized in studying behavior of molecules in intense electromagnetic fields