Antimony Co-Implantation to Suppress Boron-Penetration in P+-Poly Gate Metal-Oxide-Semiconductor Transistors

A novel method for suppressing boron-penetration is reported. Antimony co-implantation with BF2 in p-poly gate of metal-oxide-semiconductor (MOS) device is found to effectively alleviate the boron-penetration enhanced by the existence of fluorine. The boron-penetration in BF2 implanted poly-gate is observed to be significantly reduced as the dose of co-implanted antimony increases. From Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis, the suppression of boron-penetration is shown to be possibly due to the formation of Sb-F compound, which reduces the fluorine enhanced boron diffusion.