Etch Characteristics of Ge2Sb2Te5 (GST), SiO2 and a Photoresist in an Inductively Coupled Cl2/Ar Plasma

Abstract

This work reports investigations of the etch characteristics and mechanisms for Ge2Sb2Te5 (GST), SiO2 and a photoresist (PR) in a Cl2/Ar inductively coupled plasma. The etch rates were measured as functions of the Cl2/Ar mixing ratio (43 -86 % Ar), the gas pressure (4 -10 mTorr), the source power (400 -700 W), and the bias power (50 -300 W). Langmuir probe diagnostics and 0-dimensional plasma modeling provided information on the plasma parameters and plasma active species. The behavior of the GST etch rate was shown to be quite typical for ion-assisted etch processes with a dominant chemical etch pathway. The etching behavior of the PR is due to both chemical and physical etch pathway, while the etching behavior of the SiO2 is quite close to that for GST. This can be connected to the effective destruction of Si-O bonds in the thin surface layer by ion bombardment and to the reduction of SiO2 by CxHy radicals resulting from the decomposition of the PR.

Nanoscale crystallization of phase change Ge2Sb2Te5 film with AFM lithography

“…2005; Shintani et al . 2004) or dry etching (Min et al 2007; Yoon et al , 2005), the phase changed area can be used as a mask for pattern‐transfer like the anodic oxidized region of metal (semiconductor) film.…”

“…2005; Shintani et al . 2004) or dry etching (Min et al 2007; Yoon et al 2005), phase changed GST is expected to be utilized as a mask for pattern‐transfer. Thus, we believe that AFM nanolithography of phase‐change material can give diverse lithographic techniques like AFM nano‐oxidation lithography.…”

Phase change memory technology

“…There have been a number of studies of plasma etching of phase change materials such as GST and its doped variants. A variety of gas chemistries have been reported in the literature, including Cl 2 /Ar [181][182][183][184][185][186], CHF 3 /Ar [181], CF 4 /Ar [186,187], HBr/Ar [188], CHF 3 /O 2 [189,190], and CHF 3 /Cl 2 /Ar [155]. Some of these studies have examined the effects of varying process parameters such as reactant gas concentration fraction, chamber pressure, coil power, and dc bias on the etch rate and anisotropy (i.e.…”