Advanced Current-Voltage Model of Electrical Contacts to GaAs-and Ge-Based Active Silicon Photonic Devices

A new compact model, incorporating bias-dependent Schottky barrier height (SBH), is developed to precisely describe the forward-biased current-voltage characteristic of electrical contacts to Ge and GaAs layers in active silicon photonic (SiPho) components. This generic model enables direct evaluation of both the contact doping concentration and the effective barrier height of any semiconductor diode with a single-sided Schottky contact. Extracted parameters greatly agree with scanning spreading resistance microscopy (SSRM) results and literature reports. Process variabilities and design impacts were studied, and insights brought by the model enlightens future device improvements to realize Ohmic contacts.