Impact of nonlinear piezoelectric constants on surface acoustic wave propagation on a piezoelectric substrate is investigated in this work. Propagation of acoustic wave propagation under uniform stress is analyzed; the wave equation is obtained by incorporating the applied uniform stress in the equation of motion and taking account of the set of linear and nonlinear piezoelectric constants. A new method of separation between the different modes of propagation is proposed regarding the attenuation coefficients and not to the displacement vectors. Detail calculations and simulations have made for Lithium Niobate (LiNbO3); transformations between modes of propagation, under uniform stress, have been found. These results leads to conclusion that nonlinear terms affect the acoustic wave propagation and also we can make controllable acoustic devices.

Impact of nonlinear piezoelectric constants on surface acoustic wave propagation on a piezoelectric substrate is investigated in this work. Propagation of acoustic wave propagation under uniform stress is analyzed; the wave equation is obtained by incorporating the applied uniform stress in the equation of motion and taking account of the set of linear and nonlinear piezoelectric constants. A new method of separation between the different modes of propagation is proposed regarding the attenuation coefficients and not to the displacement vectors. Detail calculations and simulations have made for Lithium Niobate (LiNbO3); transformations between modes of propagation, under uniform stress, have been found. These results leads to conclusion that nonlinear terms affect the acoustic wave propagation and also we can make controllable acoustic devices.

Silicon oxide (SiO2) is a good dielectric material in metal-oxide-semiconductor (MOS) structures. The improved SiO2 quality requires adequate study of doping diffusion in this structure to maintain the absence of the different impurities in the interface Poylsilicon/SiO2. For this we studied a theoretical model of boron diffusion before and after thermal annealing in a highly-doped polysilicon films. The model takes into account the distribution of vacancy mechanism by associating parameters and effects related to high concentrations. Based on the literature the model is solved using the engineering software tool MATLAB, following a well-defined algorithm. The model is validated with the help of simulation results obtained from Silvaco.

Silicon oxide (SiO2) is a good dielectric material in metal-oxide-semiconductor (MOS) structures. The improved SiO2 quality requires adequate study of doping diffusion in this structure to maintain the absence of the different impurities in the interface Poylsilicon/SiO2. For this we studied a theoretical model of boron diffusion before and after thermal annealing in a highly-doped polysilicon films. The model takes into account the distribution of vacancy mechanism by associating parameters and effects related to high concentrations. Based on the literature the model is solved using the engineering software tool MATLAB, following a well-defined algorithm. The model is validated with the help of simulation results obtained from Silvaco.

Silicon oxide (SiO2) is a good dielectric material in metal-oxide-semiconductor (MOS) structures. The improved SiO2 quality requires adequate study of doping diffusion in this structure to maintain the absence of the different impurities in the interface Poylsilicon/SiO2. For this we studied a theoretical model of boron diffusion before and after thermal annealing in a highly-doped polysilicon films. The model takes into account the distribution of vacancy mechanism by associating parameters and effects related to high concentrations. Based on the literature the model is solved using the engineering software tool MATLAB, following a well-defined algorithm. The model is validated with the help of simulation results obtained from Silvaco.