Carrier mobility characteristics and negative bias temperature instability reliability in strained-Si p-type metal-oxide-semiconductor field-effect transistors

Surface-channel p-type metal-oxide-semiconductor field-effect transistors (pMOSFETs) processed on the strained-Si/relaxed- SiGe substrate feature significantly enhanced hole mobility (45%) compared to the unstrained-Si control device. Analysis of the mobility characteristics shows that surface roughness scattering for strained-Si pMOSFETs begins to dominate at a relatively low effective field (∼0.1 MVcm) and thus limits the drive current enhancement. In addition, experimental data indicate that negative bias temperature instability is a potential reliability concern for strained-Si pMOSFETs.