Observation of dopant profile of transistors using scanning nonlinear dielectric microscopy

Abstract

We have demonstrated that scanning nonlinear dielectric microscopy (SNDM) exhibits high performance and high resolution in observing the dopant concentration profile of transistors. In this study, we have measured standard Si samples, which are known to have one-dimensional dopant concentration values, calibrated by using conventional secondary ion mass spectrometry (SIMS). Good quantitative agreement between the SNDM signals and dopant density values was obtained by SIMS. We succeeded in visualizing high-resolution dopant profiles in n- and p-type channel MOSFET with 40 nm gate channels. It is considered that SNDM would be an effective method in measuring the quantitative two-dimensional dopant profiles of semiconductor devices. Finally, we have observed the dopant depth profiles of an SRAM memory cell by using SNDM, and succeeded in detecting the insufficient extension ion implantation in the PMOS transistor area.