Low Dit of $(2-4)\times 10^{10}$ using Y2O3/epi-Si/Ge Gate Stacks

In this work, we have achieved record-low interfacial trap densities of $(2-4) \times 10^{10}$ eV ⁻¹ cm ⁻² in the Y 2 O 3 /epi-Si/Ge(001) gate stacks, particularly low $D_{it}$ less than $1 \times 10^{11}$ eV ⁻¹ cm ⁻² near the conduction band region. Synchrotron radiation photoemission was used to probe the interfacial bonding with atomic hydrogen exposure to elucidate the effect of post-metallization annealing in forming gas. After exposure of atomic hydrogen at 400°C, a great reduction of GeO x and a great increase of SiO x formation, which is stabilized in Si ³⁺ states, suggest that the Y-O-Si formation attributed to the low $D_{it}$ .