Gate first high-k/metal gate stacks with zero SiOx interface achieving EOT=0.59nm for 16nm application

Gate first 0.59 nm EOT HfO_x/metal gate stacks for 16 nm node application are demonstrated for the first time. By controlling O during HfO_x deposition, ldquozerordquo low-k SiO_x interface (ZIL) forms despite a 1020degC activation anneal. This 0.59 nm EOT is a 30% improvement over a state of the art 32 nm HK/MG technology. We compare and demonstrate for the first time the improved scalability of ZIL HfO_x vs. exotic higher-k. Transistors made with ZIL HfO_x show good interfaces (SS=70-80 mV/dec, N_it = 5 times 10¹⁰/cm²) and performance (10% I_on-I_off boost vs. EOT = 0.95 nm), despite mobility loss. Factors contributing to mobility loss in ZIL HfO_x are discussed.