Analysis of anomalous C-V behavior for extracting the traps density in the undoped polysilicon with a double-BOX structure

A new Double-BOX structure is introduced to reveal the electrical properties of undoped polysilicon used to enhance the performance of radio frequency SOI substrates. A plateau is clearly observed in the capacitance–voltage (C-V) characteristics, which is due to the influence of the potential barrier formed at the grain boundary. A tangential approximation method based on a three-element circuit model is proposed for correcting the measured C-V curve. With the corrected C-V curve, the effective trap density distribution in polysilicon is determined for each frequency.