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 schemes has been shown to form planar contact interfaces with contact resistivities less than 1 x 10(-6) OMEGA 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 x 10(19) 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 (less-than-or-equal-to 1.5 x 10(18) cm-3), the contact resistivity increases with decreasing temperature, suggesting the dominance of the contact resistivity due to the high-low junction.