In this thesis, in order to eliminate process issue, an external mechanical uniaxial tensile and compressive stress applied on p-type metal-oxide-semiconductor field effect transistors (p-MOSFETs) is used for the study of negative bias temperature instability (NBTI) characteristics. Drain current and hole mobility decreases under uniaxial tensile strain, and the NBTI characteristics also become more serious simultaneously. And drain current and hole mobility increases under uniaxial compressive strain, and the NBTI characteristics also become less serious simultaneously. By analyzing split capacitance-voltage (C-V) characteristics, inversion charge increases and decreases due to strain induced change of band splitting and effective mass under uniaxial tensile strain and uniaxial compressive strain, respectively. According to Reaction-Diffusion model, interface trap generation rate is proportional to the number of holes in inversion layer. Therefore, the worse NBTI degradation resulted from increased inversion charge induced by uniaxial tensile strain. And the better NBTI degradation resulted from decreased inversion charge induced by uniaxial compressive strain.

We have fabricated strained Ge channel p-type metal-oxide-semiconductor field-effect transistors (p-MOSFETs) on Si₀.₃Ge₀.₇ virtual substrates. The poor interface between silicon dioxide (SiO₂) and the Ge channel was eliminated by capping the strained Ge layer with a relaxed, epitaxial silicon surface layer grown at 400° C. Ge p-MOSFETs fabricated from this structure show a hole mobility enhancement of nearly 8 times that of co-processed bulk Si devices, and the Ge MOSFETs have a peak effective mobility of 1160 cm²/V-s. These MOSFETs demonstrate the possibility of creating a surface channel enhancement mode MOSFET with buried channel-like transport characteristics. / Singapore-MIT Alliance (SMA)

PMOS and NMOS mobility characteristics of the dual channel (strained Si/strained Ge) heterostructure have been reviewed. It is shown that the dual channel heterostructure can provide substantially enhanced mobilities for both electrons and holes. However, germanium interdiffusion from the germanium rich buried layer into the underlying buffer layer could potentially reduce the hole mobility enhancements. / Singapore-MIT Alliance (SMA)