Metal-Induced Trap States: The Roles of Interface and Border Traps in HfO(2)/InGaAs

By combining capacitance–voltage measurements, TCAD simulations, and X-ray photoelectron spectroscopy, the impact of the work function of the gate metals Ti, Mo, Pd, and Ni on the defects in bulk HfO(2) and at the HfO(2)/InGaAs interfaces are studied. The oxidation at Ti/HfO(2) is found to create the highest density of interface and border traps, while a stable interface at the Mo/HfO(2) interface leads to the smallest density of traps in our sample. The extracted values of D(it) of 1.27 × 10(11) eV(−1)cm(−2) for acceptor-like traps and 3.81 × 10(11) eV(−1)cm(−2) for donor-like traps are the lowest reported to date. The density and lifetimes of border traps in HfO(2) are examined using the Heiman function and strongly affect the hysteresis of capacitance–voltage curves. The results help systematically guide the choice of gate metal for InGaAs.