An integrated semiconductor device includes a substrate, a first vertical transistor, and a second vertical transistor. The substrate has a first substrate region and a second substrate region. The first vertical transistor is disposed on the substrate in the first substrate region. The first vertical transistor is n-type field-effect vertical transistor (n-VFET) with a first channel crystalline orientation. The second vertical transistor is disposed on the substrate in the second substrate region. The second vertical transistor is p-type field-effect vertical transistor (p-VFET) with a second channel crystalline orientation. The first channel crystalline orientation is different from the second channel orientation. A common bottom source and drain region as well as common bottom and top spacers regions are provided for the first vertical transistor and the second vertical transistor.