Two dimensional dopant and carrier profiles obtained by scanning capacitance microscopy on an actively biased cross-sectioned metal–oxide–semiconductor field-effect transistor

Abstract

Scanning capacitance microscopy (SCM) was developed to measure two dimensional (2D) dopant and carrier profiles on passive semiconductor devices. This capability has now been extended for the first time to electrically biased cross-sectional devices. An electrical bias is applied to the source/drain of a device while a SCM image is being acquired. 2D SCM profiles are obtained as a function of applied bias, providing a method for determining the carrier distribution in a functioning device. The acquired SCM data is converted to carrier density using a physical conversion model developed for 2D dopant profiling. The SCM carrier profiles agree qualitatively with the predictions of device simulation. The SCM imaging of actively biased devices provides a means to directly compare electrical device characteristics with electrical device and process models. The measured carrier profiles may eventually be used to improve the accuracy of the 2D dopant profile extracted from the SCM data.