US Patent 10424515 Vertical FET devices with multiple channel lengths

A semiconductor device comprises a first source/drain region arranged on a semiconductor substrate, a second source/drain region arranged on the semiconductor substrate, a bottom spacer arranged on the first source/drain region, and a bottom spacer arranged on the second source/drain region. A first gate stack having a first length is arranged on the first source/drain region. A second gate stack having a second length is arranged on the second source/drain region, the first length is shorter than the second length. A top spacer is arranged on the first gate stack, and a top spacer is arranged on the second gate stack.