A novel etch chemistry for low-damage poly-Si gate patterning

We have investigated hydrogen iodide (HI) as an alternative to conventional chlorine or bromine silicon etch chemistries. HI plasmas seem to be a promising candidate for anisotropic polysilicon gate etching in VLSI technologies, offering high selectivity to the underlying oxide, no notching and minimal damage. The study shows that a commercially available conventional etch reactor-in combination with an unconventional etch chemistry-is well suited for gate patterning in sub-half micron technologies.