In this research, the effects of varying the reactive gas ratio during insulator deposition of MIM junctions have been observed and studied. Junctions with 100×100 μm area have been realized using Ni-NiO-Cr electrodes for Rectenna application. The electrical properties of the tunnel junctions exhibited improved tunneling response with reduced O2 gas ratio. It is theorized that a surplus of O2 ions facilitates tunneling, as does a deficiency of O2 ions due to charge transport by ions or vacancies. The devices fabricated with 1:1 and 1:3 gas ratios both exhibited high electrical responses with the latter exhibiting higher, while 1:2 exhibited the lowest response, suggesting that an increased or decreased density of traps within the barrier results in changes in the tunneling current. The dependence of voltage linearity on trap-densities within a dielectric has been shown and is discussed in this article.