III–V gate stack interface improvement to enable high mobility 11nm node CMOS

Abstract

We report significant improvements in the high-k/In_0.53Ga_0.47As interface quality by controlling atomic layer deposition (ALD) oxidizer chemistry. A step-by-step correlation between electrical data and chemical reactions at the high-k/InGaAs interface has been established using synchrotron photoemission. AsO_x, GaO_x, and In₂O₃ formed during unintentional ALD surface oxidation and the increase of As-As bonds are responsible for degrading device quality. A better quality H₂O-based high-k gate stack is evidenced by less capacitance-voltage (CV) dispersion (14% in ZrO₂), smaller CV hysteresis (37% in Al₂O₃ and 47% in ZrO₂), fewer border traps (Q_br) (96% in Al₂O₃ and 25% in ZrO₂), and lower mean interface traps density (D_it) (91% in Al₂O₃ and 29% in ZrO₂). Improvements in I_d and G_m therefore have been achieved by replacing O₃ with H₂O oxidizer. Our work suggests that H₂O-based high-k is more promising than O₃-based high-k. These results positively impact the industry's progress toward III-V CMOS at the 11nm node.