Structure and method for vertical tunneling field effect transistor with leveled source and drain

A device comprising:

• a first mesa extending from a substrate;
• a first source/drain feature disposed in the first mesa, the first source/drain feature having a first dopant;
• a second source/drain feature disposed in the first mesa and extending into the substrate, the second source/drain feature having a second dopant at a first concertation, the second dopant formed of a different material than the first dopant;
• a channel region disposed in the first mesa between the first and second source/drain features, the channel region including the second dopant at a second concentration that is different than the first concentration;
• a gate structure disposed on the first protrusion;
• and
• a pickup feature interfacing with the second source/drain feature, the pickup feature including the second dopant at a third concentration that is different than the first concentration.

A device comprising:

• a first protrusion extending from a substrate;
• a first source/drain feature disposed in the first protrusion;
• a second source/drain feature disposed in the first protrusion and extending into the substrate, the second source/drain feature including a first dopant at a first concentration;
• a gate structure disposed on the first protrusion;
• and
• a pickup feature interfacing with the second source/drain feature, the pickup feature including the first dopant at a second concentration that is different than the first concentration.