Disclosed is a semiconductor structure including a semiconductor substrate (e.g., a P-substrate) and a symmetric BDSCR. The BDSCR includes, within the substrate, a first well (e.g., a low-doped deep Nwell) and, within the first well, symmetric side sections and a middle section positioned laterally between the side sections. Each side section includes: second and third wells (e.g., Pwells), where the third well is shallower than and has a higher conductivity level than the second well. Each middle section includes multiple floating wells including: two fourth wells (e.g., Nwells), which have a higher conductivity level than the first well, and a fifth well (e.g., another Pwell), which is positioned laterally between and shallower than the fourth wells. By incorporating the floating wells into the middle section, high current tolerance is improved.