Christoph Jungemann

In 1959 the first functional MOSFET was demonstrated by D. Khang and M. Atalla with a silicon bulk, a silicon dioxide insulator and an Al gate electrode. MOS technologies soon replaced the bipolar technology for digital applications and led to the development of the modern computer, a prerequisite for device simulation. In the 1960s H. Gummel and D. Scharfetter developed the basic methods for numerical device simulation, most importantly a stabilization method for the drift-diffusion (DD) model in 1969, which is still in use today and has found many applications beyond semiconductors (e.g. ion channels). The first device simulations by H. Gummel in 1964 were for one-dimensional models of bipolar transistors. In 1969 two-dimensional device simulations were presented by J. Slotboom and soon MOSFETs were simulated with the DD model (M. Mock, 1972). The continuous scaling of the MOSFET led to the emergence of first short-channel effects, then to hot carrier effects, gate leakage currents etc. requiring more and more sophisticated simulation models. For accurate simulation of hot carrier effects, for example, a two-dimensional hydrodynamic model was introduced by B. Meinerzhagen in 1988, with which velocity overshoot and impact ionization could be simulated. At the same time models based on the more fundamental Boltzmann equation and full band structures occurred, where the Boltzmann equation was solved by the stochastic Monte Carlo method (M. Fischetti and S. Laux, 1988). With these microscopic models the distribution of the electrons and holes could be calculated directly in the phase space. Models for the quantization of the electrons confined perpendicular to the channel direction were incorporated in these semi-classical programs. Introduction of new materials and effects (high-k, SiGe, strain etc.) required further model improvements. With the transition to multi-gate MOSFETs (FinFET, nanowire and nanosheet MOSFETs) with very short gate lengths longitudinal quantum effects could no longer be neglected (e.g. source-drain tunneling) and full quantum transport models were introduced (S. Datta, 1989). These models based on ab initio methods for the calculation of the band structure and scattering processes are currently the most sophisticated transport models. They are used to explore new types of devices and materials (e.g. 2D material FETs). All these models can be found in commercial TCAD suites and form a model hierarchy, where all simulation models are used in the device development process. In this talk an overview over these simulation tools is given and some of the fundamental concepts are explained.

Biography:

Christoph Jungemann graduated in 1995 with a PhD in electrical engineering from the RWTH Aachen University, Germany. After working at Fujitsu Ltd., Kawasaki, Japan, the University of Bremen, Germany, Stanford University, USA, and the Technical University of Braunschweig, Germany, he became a Professor of Microelectronics at the Bundeswehr University in 2006. Since 2011, he has held the Chair of Electromagnetic Theory at RWTH Aachen University. He mainly works on semi-classical device modeling based on the Boltzmann equation and TCAD. He has developed algorithms for Monte Carlo simulators and numerical methods for deterministic solvers including noise analysis for silicon MOSFETs, SiGe HBTs and III-V DHBTs. He received the IEEE Paul-Rappaport-Award for 2005 and became an IEEE Fellow in 2019.

Address:RWTH Aachen University, , Germany