Influence of hydrogen on the volt-ampere and volt-farad characteristics of MIS silicon tunnel diodes

The results of a joint analysis of volt-ampere and volt-farad characteristics of a Pd-SiOx-n-Si structure with a thin (3.7 nm) oxide tunnel layer are presented. It is shown that the forward-bias region of the volt-ampere characteristic can be used to identify the dependence of the surface potential φs in Si on the voltage with consideration of the dielectric layer inhomogeneity as a function of the dielectric thickness. The probability of tunneling through the SiOx layer is estimated for local regions with the least thickness equal to 1.3 nm. When the voltage increases from 0.1 to 0.7 V, the probability of tunneling decreases from 0.78 to 0.40, whereas the potential barrier height increases from 0.04 to 0.08 eV with consideration of the mirror image forces (given that the relative SiO x permittivity is equal to 3.9). In going from the room atmosphere to a gas mixture comprising 50 vol.% of hydrogen, the positive-charge density in the dielectric increases by 8-10-7 C/cm2. Moreover, the voltage on flat bands and js decrease for local regions of a specimen with thin dielectric layers much more weakly than for most of the field electrode. ©1999 Kluwer Academic/Plenum Publishers.