Formation and electrical properties of Ni1−xFex nanocrystals embedded in a polyimide layers for applications as nonvolatile flash memories

Abstract

Self-assembled Ni1−xFex nanoparticles embedded in a polyimide (PI) matrix were formed by curing Ni1−xFex thin films with PI precursor layers. Transmission electron microscopy images and selected area electron-diffraction patterns showed that Ni1−xFex nanocrystals were created inside the PI layer. Capacitance-voltage measurements on Al/PI/nanocrystalline Ni1−xFex∕PI∕n-Si structures at 300K showed a metal-insulator-semiconductor behavior with a large flatband voltage shift due to the quantum confinement effect of the Ni1−xFex nanocrystals in spite of the possible existence of a thick tunnel PI layer, and conductance-voltage measurements showed a broad conductance peak around the flatband voltage. The present results suggest that self-assembled Ni1−xFex nanocrystals embedded in a PI layer hold promise for potential applications in nonvolatile flash memories with floating gates consisting of Ni1−xFex nanocrystals embedded in a PI layer.