Fermi level unpinning achievement and transport modification in Hf1-xYbxOy/Al2O3/GaSb laminated stacks by doping engineering.

• Interface chemistry and transport characteristics determination of Hf 1- x Yb x O y /Al 2 O 3 /GaSb gate stacks have been achieved. • Hf 1- x Yb x O y /Al 2 O 3 /GaSb (x = 0.32) gate stack has demonstrated the optimized interface stability and the suppressed leakage current density of 2.23×10^–5 A cm^-2. • The energy distribution of interface state has confirmed the achievement of the lowest interface state density of 1.98×10¹³ eV^-1 cm^-2, resulting in Fermi level unpinning. Fermi level pinning and interface instability have hindered the achievement of field-effect-transistors (FETs) with high performance. Interface passivation and doping engineering technology have become the main driving force to solve the issue. Herein, interface chemistry and transport characteristics determination of Hf 1- x Yb x O y /Al 2 O 3 /GaSb gate stacks have been achieved by passivation and doping process. X-ray photoelectron spectroscopy characterization and electrical measurements have demonstrated the existence of less intrinsic oxides and elemental Sb at Hf 1- x Yb x O y /Al 2 O 3 /GaSb interface with optimized doping content, as well as the minimum leakage current density of 2.23 × 10^–5 A cm^-2. The energy distribution of interface state based on conductance method has confirmed the achievement of the lowest interface state density of 1.98×10¹³ eV^-1 cm^-2, resulting in Fermi level unpinning. Carrier transport mechanisms of Hf 1- x Yb x O y /Al 2 O 3 /GaSb MOS capacitors as a function of temperature have been investigated systematically and some important electrical parameters have been extracted. Comprehensive analyses show that sputtering-derived Hf 1- x Yb x O y /Al 2 O 3 /GaSb (x = 0.32) gate stack has potential application in future GaSb-based metal-oxide-semiconductor field effect transistor (MOSFET) devices. [ABSTRACT FROM AUTHOR]