A Novel Analytical Model for Ohmic Contacts to Planar Devices: Theoretical Design and Experimental Verification

Designing a reasonable electrode size and obtaining precise contact resistance parameters are always crucial in the field of chip manufacturing, especially in the cases of tiny chips with very low contact resistance. In this work, an improved analytical model featuring an electrode-pair (EP) layout design is proposed to accurately extract the electrical parameters of the planar Ohmic contact. The key feature of the proposed model layout is the adoption of a series of EPs with a fixed interval distance but varied electrode widths which is just opposite to the conventional transmission line model (TLM). Then, the effective electrode width depending on the conduction current requirement and practical Ohmic contact technology level in production can hence be derived to assist the engineers for a better design in chip layout. Furthermore, the model is analyzed and demonstrated by performing both technology computer-aided design (TCAD) simulations and experimental measurements. The results verify the ability to achieve more precise contact resistance parameters and distinguish the variance of the sheet resistance underneath the contact after annealing treatment by the proposed EP model (EPM). This work provides a distinct perspective to understand and quantify the electrical characteristics in a greater variety of Ohmic contacts.