Effect of tensile strain on gate current of strained-Si n-channel metal-oxide-semiconductor field-effect transistors

In this paper, we report the effect of tensile strain on the gate current of strained-Si n-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) with an emphasis on the physical mechanism of the decrease in gate current due to strain. It is found that gate current decreases with an increase in strain and that a strain of 1.2% leads to a decrease in gate current by around one order of magnitude in a Fowler-Nordheim (F-N) tunneling current region. It is also found that this gate current decrease due to strain is attributed to an increase in barrier height for F-N tunneling current. This gate current decrease due to strain is quantitatively explained by the increase in barrier height due to a strain-induced decrease in conduction band edge energy, because of the good agreement between the increase in experimentally obtained barrier height and the reported energy change of the conduction band edge of Si.