Authors: T. Grasser, H. Kosina, M. Gritsch and S. Selberherr
Affilation: TU Wien, Austria
Pages: 474 - 477
Keywords: device simulation, impact ionization, moments method, Boltzmann's equation
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 model because it is mainly determined by the high-energy tail of the carrier distribution function. Information about the high-energy tail is lost when only the average carrier energy is taken into account. To overcome this limitation, we use the fourth moment of the distribution function to account for the population of the high-energy tail. We propose a new impact ionization model using this tail temperature and compare the results obtained with existing models and Monte-Carlo simulations which show improvements obtained by our new model.