Fang Ming Lee

Liquid-phase-deposited SiO2 on AlGaAs and its application

The silicon dioxide (SiO2) on AlGaAs prepared by liquid phase deposition (LPD) at 40 °C has been explored. The LPD-SiO2 film deposition rate is about 67 nm h−1 for the first hour. The leakage current density is about 1.21 × 10−6 A cm−2 at 1 MV cm−1. The interface trap density (Dit) and the flat-band voltage shift (ΔVFB) are 1.28 × 1012 cm−2 eV−1 and 0.5 V, respectively. After rapid thermal annealing in the N2 ambient at 300 °C for 1 min, the leakage current density, Dit, and ΔVFB can be improved to 4.24 × 10−7 A cm−2 at 1 MV cm−1, 1.7 × 1011 cm−2 eV−1, and 0.2 V, respectively. Finally, this study demonstrates the application of the LPD-SiO2 film to the AlGaAs/InGaAs pseudomorphic high-electron-mobility transistor.

Improved microwave and noise performance of InAlAs/InGaAs metamorphic high-electron-mobility transistor with a liquid phase oxidized InGaAs gate without gate recess

The metal-oxide-semiconductor metamorphic high-electron-mobility transistor (MOS-MHEMT) with an oxide grown by liquid phase oxidation on the InGaAs capping layer without a gate recess exhibits a lower leakage current density with suppressed impact ionization, better microwave characteristics, and improved high frequency noise performance compared to the conventional MHEMT with a recessed gate. The improved high frequency performance is due to the lower gate-source and gate-drain capacitances of the InAlAs/InGaAs MOS-MHEMT. Reduced surface recombination and impact ionization may also contribute to the improved frequency response, noise performance, and associated gain.

Investigation of SiO 2 on AlGaAs prepared by liquid phase deposition

The liquid phase deposition (LPD) was used to deposit silicon oxide (SiO<inf>2</inf>) layer on AlGaAs near room temperature. The LPD method is not only simple but also can obtain the SiO<inf>2</inf> very economically. Both the aqueous solution of hydro-fluosilicic acid (H<inf>2</inf>SiF<inf>6</inf>) and boric acid (H<inf>3</inf>BO<inf>3</inf>) were used for the LPD solution. After rapid temperature annealing (RTA) at 300°C for 1 min, the leakage current density is ~ 4.24 × 10⁻⁷ A/cm² at 1 MV/cm, and the interface trap density is ~ 1.7 × 10¹¹ cm⁻²eV⁻¹ for the LPD-SiO<inf>2</inf> thickness of 29 nm.

Selective Liquid Phase Oxidation of AlGaAs and Application to AlGaAs/InGaAs Pseudomorphic High Electron Mobility Transistor

The selective oxidation of AlGaAs using liquid phase oxidation and photoresist or metal as a mask is investigated, and the further application of this process for the fabrication of AlGaAs/InGaAs metal-oxide-semiconductor pseudomorphic high electron mobility transistors (MOS-PHEMTs) is explored. The stability of the oxide film after exposure to the developer solution is also evaluated. The measured f T and fm ax are 13.9 (12) and 59 (30) GHz at maximum transconductance g m for MOS-PHEMT (PHEMT), respectively. In comparison, the AlGaAs/InGaAs MOS-PHEMT is a good candidate for high speed and low noise applications.

An Analytical Model and Measurement on the InAlAs/InGaAs High-Electron-Mobility Transistor with Oxidized InAlAs Gate

The analytical model and measurement of InAlAs/InGaAs metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT) lattice-matched to InP substrate with a thin InAlAs native oxide layer are compared and achieved a good agreement, which show the validity of the proposed MOS-HEMT model.

Analytical Study of the DC Characteristics on the InAlAs/InGaAs Metamorphic HEMT with Oxidized InGaAs Gate

The analytical model is developed to calculate the sheet carrier densities of InAlAs/InGaAs metal-oxide-semiconductor metamorphic high electron mobility transistor (MOS-MHEMT) with a thin InGaAs native oxide layer and conventional MHEMT structures. The electric field, potential, and sheet carrier density versus different position within the gate length are investigated for both structures.