Local charge trapping and detection of trapped charge by scanning capacitance microscope in the SiO2/Si system

Abstract

Charge trapping induced by hot carriers in a metal–oxide–semiconductor capacitor was studied with a scanning capacitance microscope (SCM). The local charge trapping/detrapping and the readout of the trapped charge in SiO2 was performed using a SCM combined with an atomic force microscope. When applying a voltage between the conductive probe tip and the p-type silicon substrate, hot carriers injected from silicon substrate into the SiO2 generated a positive trapped charge in the 10-nm-thick SiO2 layer. The resulting shift in capacitance–voltage (C–V) curves due to the locally trapped charge was measured by the high-frequency C–V measurement. For an application to the ultrahigh density data storage field, we investigated how the charge trapping and detrapping characteristics depend on the writing speed and bias voltage.