Hydrogen passivation for reduction of SiO2/Si interface state density using hydrocarbon-molecular-ion-implanted silicon wafers

Abstract

Abstract The reduction in the density of SiO2/Si interface state (D it) in the isolation region and transfer transistor gate oxide is necessary to improve the performance of complementary metal-oxide semiconductor (CMOS) image sensors. In this study, we demonstrated that a hydrocarbon-molecular-ion-implanted epitaxial silicon wafer can reduce the D it and Pb0 center density in SiO2/Si interface regions analyzed by quasi-static capacitance–voltage and electron spin resonance measurements, respectively. The D it and Pb0 center density of wafers without hydrocarbon molecular ions increased after annealing at 700 °C. On the other hand, the D it and Pb0 center density of wafers implanted with hydrocarbon molecular ions decreased after annealing at 700 °C. We also estimated the activation energy to be 1.67 eV for the hydrogen termination reactions with hydrogen molecules and Si dangling bonds at the SiO2/Si interface. The termination effects of the hydrocarbon-molecular-ion-implanted epitaxial silicon wafers can contribute to the high electrical performance of CMOS image sensors.