Metal-Induced Trap States: The Roles of Interface and Border Traps in HfO2/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 HfO2 and at the HfO2/InGaAs interfaces are studied. The oxidation at Ti/HfO2 is found to create the highest density of interface and border traps, while a stable interface at the Mo/HfO2 interface leads to the smallest density of traps in our sample. The extracted values of D-it of 1.27 x 10(11) eV(-1)cm(-2) for acceptor-like traps and 3.81 x 10(11) eV(-1)cm(-2) for donor-like traps are the lowest reported to date. The density and lifetimes of border traps in HfO2 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.

Automated summary

The impact of the work function of gate metals Ti, Mo, Pd, and Ni on defects in HfO2 and at HfO2/InGaAs interfaces was studied using capacitance-voltage measurements, TCAD simulations, and X-ray photoelectron spectroscopy. The highest density of interface and border traps was found at the Ti/HfO2 interface, while the Mo/HfO2 interface showed the smallest density of traps. The extracted values of D-it for acceptor-like traps and donor-like traps were the lowest reported to date.