Feasibility of multiwavelength Raman spectroscopy was studied as a potential
in-line monitoring technique for grain size distribution in channel poly-Si used
in three dimensional stacked NAND (3D NAND) Flash memory devices. Various
channel poly-Si materials in 3D-NAND Flash memory devices, converted from
chemical vapor deposition (CVD) grown a-Si, were characterized using
non-contact, multiwavelength Raman spectroscopy and high resolution
cross-sectional transmission electron microscopy (HRXTEM). The Raman
characterization results were compared with HRXTEM images. The correlation
between the grain size distribution characterized by multiwavelength Raman
spectroscopy and “on current” (ION) of 3D NAND
Flash memory devices was investigated. Good correlation between these techniques
was seen. Multiwavelength Raman spectroscopy is very promising as a
non-destructive in-line monitoring technique for grain size distribution in
channel poly-Si used in 3D NAND Flash memory devices.