A review of tunneling current in high-K-based MOS capacitors: Effects of transverse-longitudinal energy coupling

Abstract

In this paper, we present a review on the development in modeling of transmittance and tunneling current through a high-K dielectric gate stack of a metal-oxide- semiconductor (MOS) capacitor by considering the coupling of transverse and longitudinal energies of an electron represented by an electron phase velocity in the gate and anisotropic masses. In order to obtain the electron transmittance and tunneling current, Airy- and exponential wavefunctions were utilized as analytical approaches. A transfer matrix method (TMM) was used as a numerical approach as a benchmark to find the best analytical approach in calculating the transmittance and tunneling current. It was shown that the Airy wavefunctions approach was a better analytical expression to calculate the transmittance and tunneling current. Furthermore, the tunneling currents computed under Airy wavefunction approach were compared to the measured ones to examine the model. It was shown that the calculated tunneling currents are fitted well by the measured ones. It was also shown that the model could be used in designing a high speed MOSFET with low tunneling current.