Electro-Thermal Analysis of Submicron Si MOSFET With Zoned Mesh Based on Semiconductor Physics Theory

The results of electro-thermal analysis, which is widely known as hydrodynamic model, are strongly dependent on the mesh size of model. However, the theory and method of accurate mesh size have not been investigated. In this research, we focus on submicron Si MOSFET and show the mesh zoning method for electro-thermal analysis. First, we explain the mesh zoning method for vertical direction, i.e. the direction from the gate oxide to the bottom surface of MOSFET, which was derived from the theory of the semiconductor physics, because the calculation results were strongly dependent on the mesh size of vertical direction. Along the vertical direction, Debye length with consideration of submicron size is the most important length scale. This Debye length is not same to the conventional one. We briefly show the derivation procedure of Debye length considered submicron phenomena and the procedure of the mesh zoning method by using this Debye length. Then, we show the error of the calculation results depended on the mesh size for the lateral direction, i.e. direction from the source electrode to the drain electrode, and we investigate the most important part in MOSFET for precise calculation.