Semiconductor Device Structure With Uniform Threshold Voltage Distribution And Method Of Forming The Same

A method, comprising:

• forming a fin structure including a source region, a drain region, and a channel region interposed between the source region and the drain region;
• processing the channel region of the fin structure such that a threshold voltage is uniform across a height of the fin structure, the processing including:
• forming a semiconductor liner layer including a dopant over the channel region of the fin structure;
• forming a first capping layer to physically contact a bottom portion of the semiconductor liner layer;
• forming a second capping layer to physically contact an upper portion of the semiconductor liner layer;
• and
• annealing the channel region of the fin structure having the semiconductor liner layer, the first capping layer, and the second capping layer thereon, the annealing causing the dopant of the semiconductor liner layer to diffuse into the channel region of the fin structure, wherein an average dopant concentration in a bottom portion of the channel region is different from an average dopant concentration in an upper portion of the channel region;
• etching the channel region of the fin structure to remove the first capping layer, the second capping layer, and the semiconductor liner layer, the etching forming a trimmed fin structure;
• and
• forming a gate structure over the channel region of the trimmed fin structure.

A semiconductor device structure, comprising:

• a fin structure extending above a dielectric isolation structure disposed over a silicon substrate, the fin structure including:
• a source region;
• a drain region;
• and
• a channel region disposed between the source region and the drain region, wherein an average germanium concentration in a bottom region of the channel region is different from an average germanium concentration in an upper region of the channel region, and wherein a threshold voltage of the fin structure is uniform across a height of the fin structure.