Impact of mechanical stress on direct and trap-assisted gate leakage currents in p-type silicon metal-oxide-semiconductor capacitors

Uniaxial four point mechanical stress-altered direct and trap-assisted gate leakage currents are measured for (100) p-type silicon metal-oxide-semiconductor capacitors with TaN gate and SiO2 dielectric. In samples where direct tunneling is dominant, tensile stress along [110] increases the gate to substrate electron tunneling, while it decreases electron tunneling from substrate to gate. An opposing dependence is observed with compressive stress. In samples where trap-assisted tunneling is dominant, gate leakage current is shown to increase for both tensile and compressive stresses, which likely results from a mechanical stress-induced decrease in trap activation energy of the SiO2∕Si interface traps.