Semiconductor device including active region with variable atomic concentration of oxide semiconductor material and method of forming the same

A fin field-effect transistor (finFET) semiconductor device comprising:

• a semiconductor substrate;
• an active fin structure protruding from the semiconductor substrate, the active fin structure comprising InGaZnO having a variable atomic concentration of oxygen ranging from about 3.8 to about 4.1;
• a first source/drain region in the active fin structure, the first source/drain region having a first atomic concentration of oxygen in the InGaZnO;
• a second source/drain region in the active fin structure spaced apart from first source/drain region;
• a channel region in the active fin structure between the first source/drain region and the second source/drain region, the channel region having a second atomic concentration of oxygen in the InGaZnO that is different from the first atomic concentration of oxygen;
• and
• a gate electrode crossing the active fin structure opposite the channel region and extending between the first source/drain region and the second source/drain region.

A semiconductor device comprising:

• a semiconductor substrate;
• an active region on the semiconductor substrate, the active region comprising InGaZnO having a variable atomic concentration of oxygen;
• a first source/drain region in the active region, the first source/drain region having a first atomic concentration of oxygen in the InGaZnO;
• a second source/drain region in the active region spaced apart from first source/drain region;
• a channel region in the active region between the first source/drain region and the second source/drain region, the channel region having a second atomic concentration of oxygen in the InGaZnO that is different from the first atomic concentration of oxygen;
• and
• a gate electrode on the channel region and extending between the first source/drain region and the second source/drain region.