Iñigo Neila “Applying numerical simulation to model SiC semiconductor devices” 2

1. Introduction.

Silicon material has been widely used in semiconductor device fabrication because of its low cost and its producibility of high quality silicon dioxide needed for impurity diffusion and surface passivation processes. However, recent development of high power electronics with progressive circuit integration bring new demands for semiconductor material used and for device fabrication, as well. Most devices, which use traditional integrated circuit technology based on silicon, are not able to operate at temperatures above 250oC, especially when high operating temperatures are combined with high-power, high frequency and high radiation environments. Since silicon technology has been well established, a silicon compatible material such as silicon carbide becomes a more favourable material for such hard, demanding and challenging conditions.

The latest developments have demonstrated SiC as a very promising electronic material, especially for use in semiconductor devices operating at high temperatures, high power, and high frequencies. These promising applications are attributed to among other SiC’s large band gap, large thermal conductivity, and large high-field drift velocity. All these properties make SiC one of the most useful semiconductor materials, which will be primarily used in the near future.

Nowadays, one of the key demands of the recent development of SiC technology is the possibility to perform simulations of sic devices with reliable and accurate results. However, still the matter in question is the credibility of physical models, currently used in such simulations. Those models were developed directly for studying silicon devices, and therefore the majority of data found in literature treat about its parameter values obtained for silicon semiconductor material. Its formulas usually cover the relevant phenomena, which occur primarily in silicon semiconductor. However, since the most of phenomena occur similarly in all semiconductor stuffs, those models can be in fact applied to numerical studies of other semiconductor materials. Such approach simply requires a suitable calibration of its parameter values for the selected semiconductor Iñigo Neila “Applying numerical simulation to model SiC semiconductor devices” 3 material. Despite that, such procedures do not usually guarantee obtaining the conceivable results. Furthermore, another passed over issue in such methods is the anisotropy phenomenon, which is usually not considered in all those models. All such considerations and approaches lead to essential difficulties in the precise and error-free device modelling of sic devices. Hence this work, in reference to such subjects, undertakes some selected issues regarding silicon carbide device modelling. Firstly, ones presents a few physical models, newly work out directly for silicon carbide device modelling, which still have not been implemented in any, known the author, commercial CAD package. In addition briefly describes the most important advantages of silicon carbide as a semiconductor material, and discusses some general issues regarding modelling of physical mechanisms occurring in semiconductors.