Inverse-narrow-width effect of deep sub-micrometer MOSFETs with LOCOS isolation

The effect of scaling down the channel width on the threshold voltage of deep submicron MOSFETs with LOCOS isolation has been investigated. Previous results, obtained from 1 μm technology and above, show an increase in threshold voltage as the width is reduced. However, in deep submicron technology, oxide thickness is scaled-down and channel doping is increased to avoid punchthrough and maintain a sufficiently high threshold voltage. This results in a threshold voltage reduction as channel width is scaled-down—the so called Inverse-Narrow-Width-Effect (INWE). The trend is explained through dopant redistribution and is verified by both experiment and process simulation. Lastly, a new narrow width threshold voltage model is proposed to account for the dopant redistribution effect.