AT – Page 5 – TechConnect Briefs

The Failure of the Hydrodynamic Transport Model for Simulation of Partially Depleted SOI MOSFETs and its Revision

Gritsch M., Kosina H., Grasser T., Selberherr S., Linton T., Singh S., Yu S., Giles M.D., TU Vienna, AT

An anomalous output characteristics is observed in hydrodynamic simulations of partially depleted SOI MOSFETs. The effect that the drain current reaches a maximum and then decreases is peculiar to the hydrodynamic transport model. It is [...]

FE-Simulation of Fast Switching Behavior of Magnetic Nanoelements

Fidler J., Schrefl T., Forster H., Suess D., Dittrich R., Vienna University of Technology, AT

Numerical micromagnetics is an essential tool to optimize magnetic storage media, spin electronic devices, such as MRAM and microsensors. The application of these devices requires a profound knowledge of the reversal mechanism. In nanostructured magnets [...]

A Physics-Based Impact Ionization Model Using Six Moments of the Boltzmann Transport Equation

Grasser T., Kosina H., Gritsch M., Selberherr S., TU Wien, AT

Due to the ever decreasing device geometries non-local effects gain more and more importance. It is particularly well known that impact ionization is not properly described by neither a local field nor a local energy [...]

A Qualitative Study on Global and Local Optimization Techniques for TCAD Analysis Tasks

Binder T., Heitzinger C., Selberherr S., Technical University Wien, AT

We compare the two well-known global optimization methods, simulate annealing and genetic optimization, to a local gradient-based optimization techniques. We rate the applicability of each method in terms of the minimal achievable target value for [...]

Variance Reduction in Monte Carlo Device Simulation by Means of Event Biasing

Kosina H., Nedjalkov M., Selberherr S., Technical University of Vienna, AT

A theoretical analysis of the Monte Carlo (MC) method for the solution of the stationary boundary value problem defined by the Boltzmann equation is briefly outlined. This analysis clearly shows how event biasing can be [...]

Transient Simulation of Ferroelectric Hysteresis

Dragosits K., Hagenbeck R., Selberherr S., Technical University of Vienna, AT

We present amodel that allows the analysis of the behavior of ferroelectric materials in a wide range of frequencies. A common approach to the transient properties of dielectrics based on differential equations was extended by [...]

Wavelet Based Matrix Compression in Numerical Micromagnetics

Schrefl T., Süss D., Fidler J., Vienna University of Technology, AT

Magnetic sensors and magneto-mechanic devices consist of spatially distinct ferromagnetic parts. Modeling their functional behavior requires to take into account the magnetostatic interactions between the magnetic elements. A hybrid finite element / boundary element method [...]

Inductance Calculation in Interconnect Structures

Harlander C., Sabelka R., Selberherr S., Technical University of Vienna, AT

We present a package based fnite elements for two and three-dimensional analyses of interconnect structures. Two preprocessors allow a layer-based input of the simulation geometry and the specification of the boundary conditions. Additionally, a third [...]

Automatic Device Design Optimization with TCAD Frameworks

Stockinger M., Selberherr S., Technical University of Vienna, AT

A design optimization method is presented which utilizes automatic optimization capabilities within TCAD frameworks. This method is applied to doping profile optimizations of ultra-low-power CMOS transistors with 0.25 and 0.1 um gate lengths. Two different [...]

Closed-Loop MOSFET Doping Profile Optimization for Portable Systems

Stockinger M., Strasser R., Plasun R., Wild A., Selberherr S., TU Vienna, AT

We present a new closed-loop simulation-based optimization process for a 100 nm MOSFET for portable systems such as subscriber units for wireless communications, yielding an almost double drive performance at equivalent stand-by power when compared [...]