Kelvin probe force microscopy for potential distribution measurement of semiconductor devices

TLDR

The study demonstrates that Kelvin probe force microscopy can be used to characterize semiconductor devices. The authors experimentally optimized KFM operating conditions, measured potential distributions on thin InGaAs resistors, and verified steep potential drops at contact edges caused by contact resistance using the transfer length method and comparison with scanning tunneling potentiometry. The measurements achieved sub‑millivolt potential deviations and monolayer‑height topographic resolution at 40–60 nm tip‑sample distances, and the KFM data accurately explain the electrical properties of the metal/semiconductor interface.

Abstract

This paper demonstrates that Kelvin probe force microscopy (KFM) is applicable to the characterization of semiconductor devices. The optimum operating conditions for KFM measurements are determined experimentally. Low potential deviation of less than several mV and high topographic resolution sufficient to display monolayer-height steps were obtained at tip-sample distances ranging from 40 to 60 nm. Potential distributions were measured on thin InGaAs resistors using KFM. The steep potential drops observed at the contact edges attributable to the contact resistance are verified by measuring the contact resistance using the transfer length method and the results of previously reported scanning tunneling potentiometry. The KFM results accurately explain the electrical properties of the metal/semiconductor interface.