Mansu Kim

Etching Characteristics and Mechanism of InP in Inductively Coupled HBr/Ar Plasma

Investigations of InP etch characteristics and mechanisms in HBr/Ar inductively coupled plasma were carried out. The etch rates of InP and the photoresist were measured as functions of HBr/Ar mixing ratio at fixed gas pressure (5 mTorr), input power (800 W), and bias power (200 W). Langmuir probe diagnostics and zero-dimensional (global) plasma modeling provided the information on plasma parameters, plasma composition, and fluxes of active species. It was found that, with variations in gas mixing ratio, the InP etch rate follows the changes in Br atom density and flux, but shows opposite behavior of the changes in H atoms and positive ions. These findings allow one to conclude that, under a given set of input process parameters, the InP etch process is not limited by the ion-surface interaction kinetics and that Br atoms are the main chemically active species.

Effect of gas mixing ratio on etch behavior of ZrO2 thin films in Cl2-based inductively coupled plasmas

This article reports a study carried out on a model-based analysis of the etch mechanism for ZrO2 thin films in a BCl3∕He inductively coupled plasma. It was found that an increase in the He mixing ratio at a fixed gas pressure and input power results in an increase in the ZrO2 etch rate, which changes from 36to57nm∕min for 0–83% He. Langmuir probe diagnostics and zero-dimensional plasma modeling indicated that both plasma parameters and active species kinetics were noticeably influenced by the initial composition of the BCl3∕He mixture, resulting in the nonmonotonic or nonlinear behaviors of species densities. Using the model-based analysis of etch kinetics, it was demonstrated that the behavior of the ZrO2 etch rate corresponds to the ion-flux-limited etch regime of the ion-assisted chemical reaction.

Etching characteristics and mechanism of Ge2Sb2Te5 thin films in inductively coupled Cl2∕Ar plasma

This work reports the investigations of both etch characteristics and mechanisms for the Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) thin films in the Cl{sub 2}/Ar inductively coupled plasma. The GST etch rates and etch selectivities over SiO{sub 2} were measured as functions of the Cl{sub 2}/Ar mixing ratio (43%-86% Ar), gas pressure (4-10 mTorr), and source power (400-700 W). Langmuir probe diagnostics and zero-dimensional (global) plasma modeling provided the information on plasma parameters and behaviors of plasma active species. From the model-based analysis of surface kinetics, it was found that with variations of the Cl{sub 2}/Ar mixing ratio and gas pressure, the GST etch rate follows the changes of Cl atom density and flux but contradicts with those for positive ions. The GST etch mechanism in the Cl{sub 2}-containing plasmas represents a combination of spontaneous and ion-assisted chemical reactions with no limitation by ion-surface interaction kinetics such as physical sputtering of the main material or the ion-stimulated desorption of low volatile reaction products.

Etch Mechanism of Ba2Ti9O20 Dielectric Thin Film in Inductively Coupled Cl2 ∕ Ar Plasma

An investigation of the Ba 2 Ti 9 O 20 (BTO) thin-film etch characteristics and mechanism in the Cl 2 /Ar inductively coupled plasma was carried out. The BTO etch rate as well as the BTO/Pt etch selectivity were measured as functions of Cl 2 /Ar mixing ratio (0-100% Ar), gas pressure (4-10 mTorr), input power (400-700 W), and bias power (50-300 W). A combination of plasma diagnostics by Langmuir probes and zero-dimensional plasma modeling provided the information on plasma parameters, gas-phase compositions, and fluxes of active species on the etched surface. It was found that the behavior of the BTO etch rate corresponds to the reaction-rate-limited etch regime, when the etch rate is limited neither by physical sputtering of the main material nor by the ion-stimulated desorption of low volatile reaction products.

Etching Characteristics of GST Thin Films using Inductively Coupled Plasma of Cl 2 -Ar Gas Mixtures

In this work, the etching characteristics of thin films were investigated using an inductively coupled plasma (ICP) of gas mixture. To analyze the etching mechanism, an optical emission spectroscopy (OES) and surface analysis using X-ray photoelectron spectroscopy (XPS) were carried out. The etch rate of the GST films decreased with decreasing Ar fraction. At the same time, high selective etch rate over films was obtained and the selectivity over photoresist films decreased with increasing the he fraction. From XPS results, we found that Te halides were formed at the etching surface and Te halides limited the etch rate of the GST films.