Corner induced non-uniform electric field effect on the electrical reliability of metal–oxide–semiconductor devices with non-planar substrates

• Non-planar MOS exhibits irregular stress induced degradation.
• Deep depletion is area dependent in planar MOS but irregular in non-planar one.
• Concave and convex corners in non-planar MOS sustain severe non-uniform E-field.

Stress induced irregular tunneling current and interface trap characteristics were observed in non-planar substrate metal–oxide–semiconductor (MOS) capacitors. The oxide electric field distributions in the concave and convex corner regions of non-planar structure are different. After stressing, the inversion tunneling current was observed to decrease gradually in non-planar sample but decrease then increase in planar one. Moreover, the non-planar sample exhibits two peaks phenomenon in interface capacitance (Cit) after stress which is different from planar one with one peak. A model describing the role of deep depletion (DD) for sample with different treatments is also proposed for the observation.