Nonisothermal device simulation using the 2D numerical process/device simulator TRENDY and application to SOI-devices

The electrical characteristics of modern VLSI and ULSI device structures may be significantly altered by self-heating effects. The device modeling of such structures demands the simultaneous simulation of both the electrical and the thermal device behavior and their mutual interaction. Although, at present, a large number of multi-dimensional device simulators are available, most of them are based on physical models which do not properly allow for heat transport and other nonisothermal effects. This paper, demonstrates that the numerical process/device simulator TRENDY provides a solid base for nonisothermal device simulation, as a physically rigorous device model of carrier and heat transport has been incorporated in the TRENDY program. With respect to the boundary conditions, it is shown that inclusion of an artificial boundary material relaxes some fundamental physical inconsistencies resulting from the assumption of ideal ohmic contact boundaries. The program TRENDY has been used for studying several nonisothermal problems in microelectronics. As an example, the authors consider an ultra-thin SOI MOSFET showing that the negative slopes in the V_ds-I_ds characteristics are caused by the temperature-dependence of the electron saturation velocity