Characteristics and mechanism of Al1.3Sb3Te etched by Cl2/BCl3 inductively coupled plasmas

• The etch rate of AST films increase with increasing of Cl2 concentration and bias power.
• The etch rate firstly increases and then decreases with increasing gas pressure or RF power.
• High etch rate, anisotropic patterning, smooth surface, and high selectivity of AST to SiO2 is possible using Cl2/BCl3 chemistry.
• XPS analysis reveals that the accumulation of low volatile SbClx on the etched surface.

Inductively coupled plasmas etching of Al1.3Sb3Te (AST) films were 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 were investigated, respectively. In addition, the X-ray photoelectron spectroscopy compositional depth profiling of the blank etched AST shows accumulation of low volatile SbClx on the etched surface. Al shows the lowest halogenide during the etching process as the volatile chlorides compounds can easily be removed from the surface during the etching process.

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