Evidence of erratic behaviors in p-channel floating gate memories and cell architectural solution

This work shows for the first time the presence of erratic phenomena in p-channel floating gate memories using Fowler Nordheim tunneling for both program and erase operations. A specific p-channel EEPROM architecture is investigated and found to be intrinsically robust against erratic behaviors. A comparison between the p-channel device and a conventional n-channel Flash is discussed and physical interpretations are suggested

Promoter Effect of Early Stage Grown Surface Oxides: A Near-Ambient-Pressure XPS Study of CO Oxidation on PtSn Bimetallics

SURFACES+YJU:EEHThe knowledge of the catalyst active phase on the atomic scale under realistic working conditions is the key for designing new and more efficient materials. In this context, the investigation of CO oxidation on the bimetallic Pt3Sn(111) surfaces by near-ambient-pressure X-ray photoelectron spectroscopy and density functional theory calculations illustrates how combining advanced methodologies allows the determination of the nature of the active phase. Starting from 300 K and 500 mTorr of oxygen, the progressive formation of surface oxides is observed with increasing temperature: SnO, PtO units first, and SnO2, PtO2 units afterward. For CO oxidation on the (2 X 2) surface, the activity gain is assigned to the build-up of ultrathin domains composed of SnO and SnO2 units. The formation of these early stage surface oxides is entirely supported by a density functional theory analysis. More generally, this study demonstrates how the catalyst surface oxidation and transformation can be better controlled by a relevant choice of environmental conditions