Utilizing embedded ultra-small Pt nanoparticles as charge trapping layer in flashristor memory cells

Abstract

In this study, a methodology for producing highly controlled and uniformly dispersed metal nanoparticles were developed by atomic layer deposition (ALD) technique. All-ALD grown thin film flash memory (TFFM) cells and their applications were demonstrated with ultra-small platinum nanoparticles (Pt-NPs) as charge trapping layer and control tunnel oxide layer. The ultra-small Pt-NPs possessed sizes ranging from 2.3 to 2.6 nm and particle densities of about 2.5 × 1013 cm–b. The effect of Pt-NPs embedded on the storage layer for charging was investigated. The charging effect of ultra-small Pt-NPs the storage layer was observed using the electrical characteristics of TFFM. The Pt-NPs were observed by a high-resolution scanning electron microscopy (HR-SEM). The memory effect was manifested by hysteresis in the IDS-VDS and IDS-VGS curves. The charge storage capacity of the TFFM cells demonstrated that ALD-grown Pt-NPs in conjunction with ZnO layer can be considered as a promising candidate for memory devices. Moreover, ZnO TFFM showed a ION/IOFF ratio of up to 52 orders of magnitude and its threshold voltage (Vth) was approximately −4.1 V using Ids−a/b – Vgs curve. Fabricated TFFMs exhibited clear pinch-off and show n-type field effect transistor (FET) behavior. The role of atomic-scale controlled Pt-NPs for improvement of devices were also discussed and they indicated that ALD-grown Pt-NPs can be utilized in nanoscale electronic devices as alternative quantum dot structures.