Observation and Utilization of Boron Segregation in Trench MOSFETs to Improve Figure of Merit (FOM)
We report the observation and utilization of boron segregation in trench MOSFETs (UMOS) to reduce on-resistance. A trenched LOCOS process has been applied to a UMOS structure to reduce the gate-to-source overlap capacitance (C gs), and it is observed that not only 40% reduction in C gs is achieved but also 45% reduction in specific on-resistance (R on, sp). Figure of merit is improved by 58%. TSUPREM-4 doping profile simulation at the silicon and oxide interface revealed the presence of boron segregation. On-resistance reduction is attributed by the shortened vertical channel length due to boron segregation.
Prediction of thermal conductivity and phonon spectral of silicon material with pores for semiconductor device
Abstract The silicon material with pores is a kind of promising semiconductor material, which greatly enhances the work efficiency with the existence of pores to reduce the thermal conductivity. To demonstrate the size effect, the non-equilibrium molecular dynamics (NEMD) method is adopted to study thermal transport in the silicon device with rectangle-shaped pores of different characteristic sizes. Great differences on the temperature distribution and on the effective thermal conductivity of the silicon device are found when the characteristic size is changed. The numerical results show that a small pore about 0.4 in porosity can introduce a 74.40% reduction in thermal conductivity at the room temperature. Besides, the related properties based on the phonon concept are explored by the phonon spectral energy density (SED) method. The results indicate the importance of considering the geometry effect in the analysis of the micro- and nanostructured silicon materials.
Accurate measurements of output characteristics and detonations of motorbike high-speed racing engine and their optimization at actual atmospheric conditions and combusted mixture composition
Abstract At a motorbike high speed racing engine there is very important an output engine characteristics which depends significantly on a detonation combustion rate, atmospheric conditions and a combusted mixture composition. The combustion process has got a relevant influence on a wear degree of main engine parts or on their damage eventually. The detonation combustion rate is very important because this kind of burning can be not only destructive but a useful phenomenon, as well. If the process of detonation burning is kept on a certain level, it can help significantly to the next increasing of an engine power output. In this article there is described the measurements of output characteristics of a high-speed racing engine which were performed by means of a data-recording system and the detonation combustion was evaluated using a quantitative method. The actual values of atmospheric conditions and the mixture composition were added to the measured values. Then the obtained values are compared visually with a damage degree of an engine piston caused by the detonation burning. The result is a limit value expressed in a number of detonation units related to a run distance interval of the vehicle driven by the high-speed racing engine. In framework of this run distance interval there is the process of detonation burning profitable. As well as it increases an engine power output and together it is not destructive with regard to engine design parts.