From Resistor-Only to Resistor-to-Schottky Barrier Ohmic Contact Model to Investigate Current-Voltage Characteristics of Ohmic Contacts

<p dir="ltr">Low-resistance metal-to-semiconductor ohmic contacts are critical for modern semiconductor devices. As transistor dimensions shrink, contact resistance has an increasingly significant effect on power consumption and switching speeds. Ohmic contact test structures are commonly used to characterise Specific Contact Resistivity, a key metric of contact quality. However, conventional resistive-only network models often overlook quantum physics principles critical to metal-semiconductor interfaces, leading to inaccuracies in modelling advanced devices. This thesis addresses these limitations by integrating quantum mechanical tunnelling and Fermi-Dirac statistics into a revised current-transport model. Using Synopsys Sentaurus TCAD, a 3D two-contact circular test structure is modelled and compared with conventional resistive-only models, revealing significant deviations due to non-linear behaviour. The revised model accurately describes the current voltage characteristics and SCR, with validation through TCAD simulations and published experimental data across varying parameters, including doping levels, Schottky barrier heights, and operating temperatures. A key contribution of this work is the introduction of the Resistor-to-Schottky Barrier (RSB) model, a novel analytical framework for Transmission Line Model test structures. By incorporating miniature Schottky barriers in its distributed network, the RSB model overcomes the limitations of traditional resistive-only test structures. Validation confirms its reliability, while analyses highlight phenomena such as high current density at contact edges and its implications for contact lifetime. The RSB model offers a robust tool for comprehensively understanding quantum effects in metal-semiconductor contacts and has the potential for broader applications in contact characterisation and design.</p>