Kelvin probe force microscopy for potential distribution measurement of semiconductor devices

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.