Reduction of Fermi-Level Pinning and Controlling of Ni/β-Ga₂O₃ Schottky Barrier Height Using an Ultrathin HfO₂ Interlayer

Abstract

Achieving precise control of the Schottky barrier height and minimizing Fermi-level pinning effect are crucial factors in designing high-performance Schottky barrier diodes. In this work, the effect of insertion of HfO2 with different cycle numbers on forward current, capacitance, and Ni/HfO2/β-Ga2O3 Schottky barrier height is discussed. First, we observed that Schottky barrier heights extracted from capacitance (ϕB CV) were adjusted in the range of 0.54–1.33 eV, in which it was increased by repeated atomic layer deposition cycles from two to eight. In addition, with increasing HfO2 cycle numbers, the Schottky barrier height became similar to an ideal value, which means the Fermi pinning level effect is reduced. The effects of HfO2 cycle numbers on forward current and on the extracted Schottky barrier height (ϕB JV) were analyzed. We observed that, the forward current was highly dependent on the HfO2 cycle number. Schottky barrier height (ϕB JV) can be controlled easily in a wide range domain from 1.05 to 1.48 eV by increasing HfO2 cycle numbers.

A Review of β-Ga2O3 Power Diodes

“…Furthermore, the sidewall depletion effect of the p-NiO was enhanced with a reduction in fin width, resulting in a decreased reverse leakage current. Metal-dielectric-semiconductor (MDS) HJDs were fabricated by inserting an insulating dielectric layer between the metal and β-Ga 2 O 3 , effectively enhancing the device's reverse characteristics while generally observing a decrease in forward performance, and they will not be discussed in detail here [230][231][232][233][234].…”