The temperature dependence of the contact resistivity of the Si/Ni(Mg) nonspiking contact scheme on p-GaAs

The temperature dependence of the contact resistivity of the Si/Ni(Mg) nonspiking contact scheme on p-GaAs has been investigated. This contact scheme has been shown to form planar contact interfaces with contact resistivities less than 1 × 10−6 Ω cm2. This investigation demonstrates that the contact resistivity can be modeled by a sum of two components in series: (i) a contact resistivity due to the metal-GaAs interface and (ii) a contact resistivity due to the high-low junction formed between the highly doped regrown GaAs layer and the substrate. For degenerately doped samples (4.5 × 1019 cm−3), the contact resistivity is nearly independent of the temperature from 300 to about 30 K, indicating that the dominant resistivity is that across the metal-semiconductor tunneling barrier. For samples with lower doping concentrations (≤ 1.5 × 1018 cm−3), the contact resistivity increases with decreasing temperature, suggesting the dominance of the contact resistivity due to the high-low junction.