Structural And Morphological Properties of Nitrogen-Doped Polysilicon for Advanced Gate Material

Deposition of N-doped poly-Si films from SiH4 and NH3 using a single wafer type LPCVD system was investigated to improve the grain size reduction and the grain size distribution. The deposition rate and surface roughness of N-doped Si were greatly affected by the NH3/SiH4 ratio such that they decreased with increasing NH3/SiH4 ratio. XRD and TEM measurements revealed that with increasing NH3/SiH4 ratio, the size of the grains was decreased and the grains size distribution got uniform. Finally, we successfully obtained N-doped poly-Si films having uniform grain size belo