title: A scanning microscopy technique based on capacitive coupling with a field-effect transistor integrated with the tip.
abstract: We propose a method for measuring the capacitance of a thin layer using a Tip-on-Gate of Field-Effect Transistor (ToGoFET) probe. A ToGoFET probe with a metal-oxide-semiconductor field-effect transistor (MOSFET) with an ion-implant channel was embedded at the end of a cantilever and a Pt tip was fabricated using micro-machining. The ToGoFET probe was used to detect an alternating electric field at the dielectric surface. A dielectric buried metal sample was prepared; a sinusoidal input signal was applied to the buried metal lines; and the ToGoFET probe detected the electric field at the tip via the dielectric. The AC signal detected by the ToGoFET probe was demodulated by a simple AC-to-DC converter. Experimentally, it was shown that an electric field could be measured at the surface of the dielectric layer above a buried metal line. This promising result shows that it is possible to measure the surface local capacitance.
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Republic of Korea.
authors.forename: Kumjae
authors.initials: K
authors.lastname: Shin
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Republic of Korea.
authors.forename: Dae sil
authors.initials: Ds
authors.lastname: Kang
authors.affiliation: Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology (SeoulTech), Republic of Korea.
authors.forename: Sang hoon
authors.initials: Sh
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Republic of Korea. Electronic address: wkmoon@postech.ac.kr.
authors.forename: Wonkyu
authors.initials: W
authors.lastname: Moon
keywords: Amplitude modulation; Local capacitance; Metal-oxide-semiconductor transistor; Scanning probe microscopy; Surface electric field