Taiwan Semiconductor Manufacturing Company Limited
Transistors with Enhanced Dopant Profile and Methods for Forming the Same

Abstract:

A planar insulating spacer layer is formed over a substrate, and a vertical stack of a gate electrode, a gate dielectric layer, and a first semiconducting metal oxide layer may be formed thereabove. The first semiconducting metal oxide layer includes atoms of a first n-type dopant at a first average dopant concentration. A second semiconducting metal oxide layer is formed over the first semiconducting metal oxide layer. Portions of the second semiconducting metal oxide layer are doped with the second n-type dopant to provide a source-side n-doped region and a drain-side n-doped region that include atoms of the second n-type dopant at a second average dopant concentration that is greater than the first average dopant concentration. Various dopants may be introduced to enhance performance of the thin film transistor.