High electrical performance liquid-phase HBr oxidation gate insulator of InAlAs/InGaAs metamorphic MOS-mHEMT

The InAlAs/InGaAs metal–oxide–semiconductor metamorphic high electron mobility transistors (MOS-mHEMTs) were demonstrated by using liquid-phase HBr treatment technology to form a high-quality gate insulator layer. In this study, liquid-phase HBr treatment technology was used instead of traditional plasma-assisted chemical vapor deposition (PECVD) because the proposed technology can prevent the device from plasma-induced damage. The novel HBr + ultraviolet (UV) illumination treated InGaAs provided a lower surface states such that MOS structure can be efficiently obtained. Besides, based on the atomic force microscopy (AFM) measurement, the native oxides film formed by HBr + UV illumination treatment also provided a better surface roughness compared to traditional NH4OH and only HBr treatment solutions. It is beneficial for reducing the surface traps and lowering the leakage current in MOS-mHEMTs. Based on the flicker noise and load-pull power measurement results, HBr + UV treatment mHEMT achieved a low flicker noise at high current level and the power-added efficiency can be enhanced up to 9%. Therefore, the novel liquid phase method of HBr + UV illumination treatment exhibited a highly potential for low noise microwave power device applications.