For the system on panel applications, we fabricated and analyzed the polycrystalline silicon (poly-Si) silicon-oxide-nitride-oxide-silicon (SONOS) memory device on different buffer layer such as oxide or nitride. The threshold voltage (VT) and transconductance (gm) are extracted from each device and the X-Ray Diffraction (XRD) measurement is carried out to interpret these characteristics. The results show the device on oxide layer has higher mobility and lower VT than on nitride layer. From the XRD spectra, it can be explained by the fact that the grain size of poly-Si on oxide layer has larger than on nitride layer. The both devices show program/erase characteristics as the potential of SOP memory devices.