Comparison of structural and electrical properties of praseodymium oxide and praseodymium titanium oxide charge trapping layer memories

摘要

The structural properties and electrical characteristics of metal-oxide-nitride-oxide-silicon memory structure by using praseodymium oxide (Pr_2O_3) or praseodymium titanium oxide (PrTi_xO_y) to replace silicon nitride as the charge storage layer [resulting structure is termed metal-oxide-high-k material-oxide-silicon (MOHOS) devices] were investigated. The structural and morphological features of these high-k films were analyzed using x-ray diffraction, scanning electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. It was found that MOHOS memory prepared under the PrTi_xO_y film and annealed at 800℃ exhibited a large flatband voltage shift of 5.6 V and low charge loss of ～6% at room temperature. We attribute this behavior to the titanium content in the Pr_2O_3 film, suppressing interfacial SiO_2 and silicate from forming at the PrTi_xO_y/oxide interface and enhancing nanocrystal formation.