Characterising lateral capacitance of MNOSFET with localised trapped charge in nitride layer

This paper discusses the limitations of scanning microscope to read localised charge and proposes a viable solution. A 2D simulation and characterisation of the capacitance-voltage (C-V) characteristics of the lateral source-base transition of metal-nitride-oxide-semiconductor field effect transistor (MNOSFET) with charge trapped in nitride layer is presented. It is shown that C-V dependence is changed after trapping the localised charge in nitride layer. The change depends on position of the localised trapped charge. An n-channel transistor is considered with acceptor concentration in base of 1016 cm−3. By localising a charge bit with linear size of 80 nm in nitride layer, it is observed that capacitance jump in C-V dependence starts at some bias voltage applied to the source-base transition. This voltage depends on the position of charge bit. This dependence can be used in determining the charge bit position in the nitride layer along channel. To the best of the author’s knowledge, it is one of the most efficient methods in scanning localised charge.