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.
Redistribution of Acceptor and Donor Impurities during Thermal Oxidation of Silicon
The redistribution of impurities during thermal oxidation of silicon was studied both theoretically and experimentally. Experiments with specific impurities indicate that gallium, boron, and indium deplete from silicon, while phosphorus, antimony, and arsenic pile up during thermal oxidation. It is shown that the redistribution process can be significantly influenced by the escape of impurities through the oxide layer as well as by the segregation of the impurity at the oxide‐silicon interface.
Interaction of Formaldehyde and Tetrahydrofolic Acid and Its Relation to the Enzymic Synthesis of Serine
Interaction of Formaldehyde and Tetrahydrofolic Acid and Its Relation to the Enzymic Synthesis of Serine