Patent ID: 9312378
Filing Date: 2016-04-12
CPC Classification: H01L

Claim Text:
1. A transistor comprising: a semiconductor substrate; a gate dielectric layer disposed on the semiconductor substrate; a silicon nitride layer, disposed on the gate dielectric layer and including a double layer structure including a nitrogen-rich layer on the gate dielectric layer and a silicon-rich layer on the nitrogen-rich layer, such that the double layer structure includes a stepped band gap provided by the silicon-rich layer having a band gap and the nitrogen-rich layer having a different band gap, wherein an atom number ratio of nitrogen atoms to silicon atoms in the nitrogen-rich layer is greater than about 1.2, and the nitrogen-rich layer has a thickness ranging from about 1 nm to about 4 nm; a gate electrode layer disposed on the silicon nitride layer, wherein the silicon nitride layer includes a first surface in contact with the gate dielectric layer and a second surface opposite to the first surface, the second surface including silicon atoms having a concentration higher than the first surface; a sidewall spacer disposed on the semiconductor substrate and along sidewalls of each of the gate electrode layer, the silicon nitride layer, and the gate dielectric layer; and a source region and a drain region within the semiconductor substrate on both sides of the gate electrode layer and the sidewall spacer.