The comprehensive study of liquid phase oxidation on GaAs-based transistor applications
The GaAs-based HEMTs with gate oxide and HBTs with surface passivation prepared by liquid phase oxidation (LPO) will be demonstrated. As compared to the Schottky-gate HEMTs, the lower gate leakage currents, higher breakdown voltages, and improved RF performances make the proposed technique suitable for high-power and high-speed applications. Moreover, the HBTs with oxide passivation possess the characteristics of lower surface recombination currents, higher breakdown voltage, and improved higher dc current gain.
Liquid phase oxidation for InGaP/GaAs HBT passivation
Native oxide films grown near room temperature by liquid phase oxidation (LPO) on p+-GaAs, n-InGaAs and n-InGaP are investigated. Their applications to heterojunction bipolar transistors (HBTs) are also demonstrated and characterized. With the LPO as surface passivation, the dc current gain β of the HBT devices increases sevenfold in low collector current regimes, and it also shows wider collector regimes from 8.3 × 10−11 A to 0.1 A. In addition, a larger breakdown voltage and lower surface recombination current can be obtained. This provides the possibility of promising implementations in low-power electronics and communication applications. Comparisons between devices with LPO passivation and those with sulfur treatment on the InGaP/GaAs HBTs are also discussed.
Anodic oxidation of AlxGa1−xAs
A new anodic oxidation technique for AlxGa1−xAs is developed. N‐methylacetamide adjusted to a pH value of 8.0–8.5 by NH4OH can be used as an electrolyte. The oxide growth rate of AlxGa1−xAs and the amount of AlxGa1−xAs consumed in the process are independent of the mole fraction x of AlAs in AlxGa1−xAs solid, and they are 22.9 and 14.3 A/V, respectively, when grown at a constant current density of 0.5 mA/cm2.