Dependence of the I-V curve of a metal insulator semiconductor switch on insulator thickness - an experimental and theoretical investigation

Although the metal insulator semiconductor switch (Al/SiO₂/n-Si/p-Si) has been investigated for quite some time, there has been no systematic report on the influence of the oxide thickness on the current-voltage (I-V) curve. We fabricated four types of metal insulator semiconductor switches where the only intentional difference was the thickness of the oxide. We observed, both experimentally and by simulation, that the I-V curves of these devices are very sensitive to the oxide thickness. While the simulated curves only agree with the measured ones in certain trends, the simulation provides some insight to the operation of the device. The onset of the negative resistance region in the curve is so sensitive to the electron and hole tunneling currents that the these devices could be used to characterize ultrathin oxides. Extremely high current densities (10³ A/cm²) have been driven through the ultrathin oxides without significantly changing the device characteristics. We believe this is the highest, steady-state, current density through an oxide reported to date.