Fluorine improvement of MOSFET interface as revealed by RTS measurements and HRTEM

Abstract

The MOSFET flicker (1/f) noise is reduced by 1 to 2 orders by incorporating fluorine into the oxide-silicon interface. This is attributed to a reduction in interface state density with fluorine as confirmed by charge pumping measurements. Random-Telegraph Signal (RTS) noise measurements on small-size MOSFETs show a considerable increase in the on-off time-constants with fluorine. High-resolution TEM micrographs show the presence of an interface transition layer on samples without fluorine but not with fluorine. It is believed that a transformation of this layer causes a reduction in noise and an increase in oxide thickness.