TU Vienna – TechConnect Briefs

Impact of Multi-Trap Assisted Tunneling on Gate Leakage of CMOS Memory Devices

Entner R., Gehring A., Kosina H., Grasser T., Selberherr S., TU Vienna, AT

In this work a new approach for modeling gate leakage currents for memory cells which are highly degraded is proposed. In thicker dielectrics which are subject to high field stress and can therefore have a [...]

A Physically-Based Electron Mobility Model for Strained Si Devices

Dhar S., Kosina H., Palankovski V., Ungersboeck E., Selberherr S., TU Vienna, AT

A model describing the mobility tensor for electrons in strained Si layers as a function of strain is presented. It includes the effect of strain-induced splitting of the conduction band valleys in Si, inter-valley scattering, [...]

An Impact Ionization Model Including an Explicit Cold Carrier Population

Grasser T., Kosina H., Heitzinger C., Selberherr S., TU Vienna, AT

Conventional macroscopic impact ionization models which use the average carrier energy as main parameter cannot accurately describe the phenomenon in modern miniaturized devices. Here we present a new model which is based on an analytic [...]

Non-Parabolicity and Non-Maxwellian Effects on Gate Oxide Tunneling

Gehring A., Grasser T., Selberherr S., TU Vienna, AT

Simulation of gate oxide tunneling currents in subquartermicron devices requires correct modeling of the electron energy distribution function in the channel region. However, the common assumption of a heated Maxwellian distribution function leads to a [...]

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 [...]

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 [...]

A New Analytical Energy Relaxation Time Model for Device Simulation

Palankovski V., Kosina H., Hernandez A., Selberherr S., TU Vienna, AT

We present an empirical model for the electron energy relaxation time. It is based on Monte-Carlo simulation results and is applicable to all relevant diamond and zinc-blende structure semiconductors. The energy relaxation times are expressed [...]

Accurate Three-Dimensional Simulation of Damage Caused by Ion Implantation

Hössinger A., Selberherr S., TU Vienna, AT

We present a Monte-Carlo ion implantation simulation method that allows a very accurate prediction of implantation induced point defects, generation of amorphous areas, and impurity distributions. The implanted impurity profiles can be calculated as well [...]

Numeric Aspects of the Simulation of Two-Dimensional Ferroelectric Hysteresis

Dragosits K., Selberherr S., TU Vienna, AT

Simulation of ferroelectric hysteresis allows the analysis of nonvolatile memory cells which are based on ferroelectric materials. We give an overview of our algorithm for the calculation of effects caused by field rotation. Implementation of [...]