Gate Direct Tunneling Currents in Uniaxial Stressed MOSFETs

We present a simple physical picture for uniaxial stress altered gate direct tunneling current in n and p-channel metal-oxide-semiconductor field effect transistors (MOSFETs). Experimental data shows that the nMOSFET gate electron tunneling current decreases (increases) for uniaxial tensile (compressive) stress. The pMOSFET stress altered gate hole tunneling current is opposite to the electron current. These results can be understood from the strain-altered out-of-plane effective mass, energy splitting, and carrier population. For instance, longitudinal uniaxial tensile stress increases barrier height and the electron population in the ¿2 valleys that have a higher out-of-plane mass resulting in reduced electron tunneling current. Whereas in p-channel MOSFETs, uniaxial tensile stress increases the hole tunneling current by decreasing the hole population in the top band with has a higher out-of-plane mass.