Enhanced drivability of high-Vbd dual-oxide-based complementary BEOL-FETs for compact on-chip pre-driver applications

Enhanced current drivability of BEOL-process-compatible dual-oxide complementary BEOL-FETs on LSI-interconnects (Fig. 1) with just two additional masks to the state-of-the-art BEOL process is demonstrated, aiming at high-V_bd pre-driver operation. We have developed processes so that IGZO-based NFETs have lower AR_on as compared to currently available Si power devices (Fig. 6). We also developed new SnO processes, realizing a 30× I_on boost for PFETs. Dual oxide semiconductor channels are integrated to form BEOL-CMOS inverters with stable and sharp cut-off characteristics (Figs. 8 and 9) for lower power operation, leading to a successful operation of an integrated 6T-SRAM cell (Fig. 11). Pre-driver capability of NFET inverters is demonstrated with MCU-controlled operation of brushless DC (BLDC) motors (Fig. 12). This technology is a strong candidate to realize high-V_bd pre-drivers and low-power logic on BEOL, which gives standard LSIs a special add-on function for smart society applications.