US Patent 10354921 Stacked transistors with different channel widths

A semiconductor device includes a first gate stack arranged about a first nanowire and a second nanowire, the first nanowire is arranged above a second nanowire, the first nanowire is connected to a first source/drain region and a second source/drain region. A second gate stack is arranged about a third nanowire and a fourth nanowire, the third nanowire is arranged above a fourth nanowire, the third nanowire is connected to a third source/drain region and a fourth source/drain region. An insulator layer having a first thickness is arranged adjacent to the first gate stack.