Characterization of oxide tarps in 28nm p-type metal-oxide-semiconductor field-effect transistors with tip-shaped SiGe source/drain based on random telegraph noise

In this study, the impact of embedded tip-shaped SiGe in the source/drain (S/D) region on individual trap behavior such as activation energy and depth from the SiO ₂/Si interface of the 28nm p-type metal-oxide- semiconductor field-effect transistors (pMOSFETs) has been investigated on the basis of drain current random telegraph noise (RTN). The purpose of implementing tip-shaped SiGe S/D is to further increase channel stress because it provides a closer proximity of embedded SiGe to the channel. By characterizing RTN, we found that the pMOSFETs underwent uniaxial compressive strain that was provided by tip-shaped SiGe S/D, and the trap energy level being close to the channel valence band resulted in the trap located close to the Si/SiO ₂ interface, as compared with the control device without embedded SiGe S/D.