Photo-induced tunneling currents in MOS structures with various HfO2/SiO2 stacking dielectrics

Abstract

In this study, the current conduction mechanisms of structures with tandem high-k dielectric in illumination are discussed. Samples of Al/SiO2/Si (S), Al/HfO2/SiO2/Si (H), and Al/3HfO2/SiO2/Si (3H) were examined. The significant observation of electron traps of sample H compares to sample S is found under the double bias capacitance-voltage (C-V) measurements in illumination. Moreover, the photo absorption sensitivity of sample H is higher than S due to the formation of HfO2 dielectric layer, which leads to larger numbers of carriers crowded through the sweep of VG before the domination of tunneling current. Additionally, the HfO2 dielectric layer would block the electrons passing through oxide from valance band, which would result in less electron-hole (e−-h+) pairs recombination effect. Also, it was found that both of the samples S and H show perimeter dependency of positive bias currents due to strong fringing field effect in dark and illumination; while sample 3H shows area dependency of positive bias currents in strong illumination. The non-uniform tunneling current through thin dielectric and through HfO2 stacking layers are importance to MOS(p) tunneling photo diodes.

A highly sensitive broadband planar metal-oxide-semiconductor photo detector fabricated on a silicon-on-insulator substrate

“…The role of illumination is described in Ref. 12. Another reason of the shift of V fb towards the negative bias side can be the influence of the increase of the depletion region capacitance under illumination.…”

Improvement in the breakdown endurance of high-κ dielectric by utilizing stacking technology and adding sufficient interfacial layer

“…The method of NAO is also available in forming Al 2 O 3 from Al metal [20]. Some research focused on the enhancement of illumination and temperature sensitivity by using NAO process to form HfO 2 on interfacial layer (IL) [21,22]. Furthermore, since NAO is carried out at room temperature, multi-stacking structures could be achieved without the consideration of thermal budget, and each stacking layer could also be fully oxidized in order to reach optimal quality of dielectric structure.…”

“…Several studies on the trapping characteristics of stacking structure Al 2 O 3 and HfO 2 had been proposed [23,24]. The research of tunneling current characteristics in dark and illumination was also explored on stacking structure [21]. It is believed that the process control of stacking technology for devices with better performance and reliability is still of interest.…”

Hysteresis modeling in graphene field effect transistors

“…38 At negative bias, photons of energy c ¼ hx generate hot electrons in the gate metal which are then injected into the conduction band of the dielectric due to the applied electric field. These electrons are either scattered into trap states in the dielectric or tunnel through the oxide.…”