| abstract |
A method for fabricating a semiconductor device including multiple pairs of threshold voltage (Vt) devices includes forming a stack on a base structure having a first region corresponding to a first pair of Vt devices, a second region corresponding to a second pair of Vt devices and a third region corresponding to a third pair of Vt devices. The stack includes a first dipole layer, a first sacrificial layer formed on the first dipole layer, a second sacrificial layer formed on the first sacrificial layer, and a third sacrificial layer formed on the second sacrificial layer. The method further includes forming a second dipole layer different from the first dipole layer. |