Quantification of scanning capacitance microscopy imaging of the pn junction through electrical simulation

Determining the cross-sectional doping profile of very small metal-oxide-se miconductor field effect transistors and specifically the direct measuremen t of their channel length is necessary for true channel engineering to be p ossible. Scanning capacitance microscopy (SCM) has generated unprecedented images of the cross-sectional doping profiles of very small transistors. Th e bias voltage dependence of these images has motivated us to investigate t he SCM technique in greater detail. Using electrical simulations, we have f ocused on the pn junction to establish the qualitative and quantitative rel ationship between the bias voltage and the pn junction location. The abilit y to confidently interpret the images produced with SCM will allow us to im prove simulation models, trouble-shoot process flow, and determine the effe ctive channel length of semiconductor devices. (C) 1999 American Institute of Physics. [S0003-6951(99)01502-8].