Characteristics and mechanism of phase change material W0.03Sb2Te etched by Cl2/BCl3 inductively coupled plasmas

Inductively coupled plasma (ICP) etching of phase change material W0.03Sb2Te (WST) films is studied using Cl2/BCl3 gas mixture. The effects of gas-mixing ratio, bias power, gas pressure, applying ICP power on the variations of etch rate, etch profiles, and surface roughness are investigated, respectively. The etch rate is found proportional to the ICP power but inversely proportional to the flow of BCl3. The etching profile is related to gas ratio and bias power. In addition, the X-ray photoelectron spectroscopy compositional depth profiling of the blank etched WST shows accumulation of low volatility WClx and SbClx on the etched surface.