Revealing the structure of SiO2 and its effects on electrical properties

In this paper, the effects of vacancies and dopants on alpha-SiO2 are fully investigated with the first principle calculation and the finite element analysis method. The vacancies and dopants including the oxygen vacancy, silicon vacancy, boron dopant, and phosphorous dopant are considered. The oxygen vacancy, P substituted with O, and Si substituted with B are the most stable in the process of the oxide growth leading to the multi-layer microstructure of the tunneling oxide on the silicon substrate, and their concentrations increase with the temperature. Si substituted with B has larger capture cross sections than the other two types. The SONOS FLASH structure is built with the realistic manufacturing process to clarify the electrical effect of the multi-layer. The programming process with introduced levels from vacancies and dopants will be weakened with less charges storing in the floating gate which can reduce the circuit performance. The theoretical study from the electronic structure to electrical properties has remarkable senses for manufacturing devices and improving device performance in the future.