Scanning spreading resistance microscopy for carrier profiling beyond 32nm node

With the continued scaling of CMOS devices down to 32nm node and beyond, device performance is very sensitive to the lateral diffusion mechanisms influencing the effective channel length. Tools are thus, required to measure with sufficient resolution and accuracy the carrier distribution. Scanning spreading resistance microscopy (SSRM) has evolved as a successful carrier-profiling technique with sub-nm resolution, less than 2 nm/decade gradient resolution and high dynamic range 10¹⁵ to 10²¹ cm^-3. In this work, we present the approaches (methodology and special test structures) to obtain a 3D-carrier concentration map for FinFET-based devices. We also correlate the results obtained with SSRM for various process conditions and its implications on device performance.