A comparative study of different contact resistance test structures dedicated to the power process technology

This paper presents different contact test structures intended to characterize the metal-semiconductor interface (aluminum-silicon) for power integrated circuits fabricated in the Application Specific Discrete (ASD™) process technologies. For this study, three contact test structures have been selected, transfer length method (TLM), cross bridge Kelvin resistance (CBKR), and contact end resistance (CER). The characterization is achieved by extracting the specific contact resistance (ρC) from contact test structures by measuring the contact resistance (RC). To validate the results, spreading resistance was used to determine the surface doping concentration (CS) of the diffused layer that gives ρC from a well know standard abacus. From the experimental results, we conclude that only the TLM test structure is able to give correct values of the specific contact resistance for both n and p type diffused layers that are compatibles with the manufacturer specifications.