| CPC H01L 29/775 (2013.01) [H01L 29/1054 (2013.01); H01L 29/66439 (2013.01)] | 20 Claims |

|
1. A method, comprising:
etching a substrate to form a core structure protruding out of a plane of the substrate;
forming shallow trench isolation (STI) features on opposite sides of the core structure;
doping the substrate and a lower portion of the core structure to form a first source/drain region with a first doping concentration;
growing a barrier layer on an upper portion of the core structure;
forming a first spacer covering the STI features and covering the lower portion of core structure;
forming a shell wrapping the upper portion of the core structure and the barrier layer, wherein the shell and the upper portion of the core structure have different doping conductivity types;
forming a second source/drain region with a second doping concentration over the shell, wherein the first doping concentration and the second doping concentration are different from each other; and
forming a first gate around the shell.
|