Synthesis of Diamond‐Like Carbon Films Deposited by the Ionization Vapor Method and Development of its Semiconductive Devices Fabricated by the Focused Ga Ion Beam Implantation

Abstract

In this study, we have attempted to synthesize the Gallium (Ga)-implanted diamond-like carbon (DLC) film for new functional devices as substituting Si-based materials. Intrinsic-DLC (i-DLC) films (energy gap: 1.45 eV) were deposited by the ionization vapor method with applying the negative pulsed bias voltage (frequency: 2 kHz, duty ratio: 30%, peak voltage: 500 V) to SiO2 substrates. Ga atoms were implanted to i-DLC films as accepters utilizing by focused ion beam irradiation system. The Raman scattering spectra of i-DLC and Ga-DLC films showed typical DLC characteristics which consisted of I(D) and I(G) peaks. In order to evaluate working function of the Ga-DLC film, several electrode materials (Au, Pt, Cu, Al, and Sn) were deposited on the films. Current-voltage characteristics of Au and Pt electrodes on Ga-DLC films showed Ohmic contacts, and Cu, Al, and Sn electrodes were Schottky contacts. These results suggested that a work function of the Ga-DLC film was in the range of 4.47 eV to 4.58 eV. To apply these contact properties to DLC semiconductive devices, we produced the DLC Schottky diode using Al and Pt electrodes deposited on the Ga-DLC film. A currentvoltage characteristic of DLC Schottky diode showed diode property in which amount of forward and backward voltage were 7.0 V and 17.0 V, respectively. The ideality factor n of produced diode was 11.3. C⃝ 2018 Wiley Periodicals, Inc. Electron Comm Jpn, 101(4): 34-41, 2018; Published online in Wiley Online Library (wileyonlinelibrary.com).