Jung-Sheng Huang

This study presents the fabrication and improved properties of an AlGaAs/InGaAs metal-oxide-semiconductor pseudomorphic high-electron-mobility transistor (MOS-PHEMT) using liquid phase deposited titanium dioxide (LPD-TiO₂) as a gate dielectric. Sulfur pretreatment and postoxidation rapid thermal annealing (RTA) were consecutively employed before and after the gate dielectric was deposited to fill dangling bonds and therefore release interface trapped charges. Compared with a benchmark PHEMT, the AlGaAs/InGaAs MOS-PHEMT using LPD-TiO₂ exhibited larger gate bias operation, higher breakdown voltage, suppressed subthreshold characteristics, and reduced flicker noise. As a result, the device with proposed process and using LPD-TiO₂ as a gate dielectric is promising for high-speed applications that demand little noise at low frequencies.

Both β‐FeSi₂ and BaSi₂ are silicides and have large absorption coefficients; thus they are very promising Si‐based new materials for solar cell applications. In this paper, the dc I‐V characteristics of n‐Si/i‐βFeSi₂/p‐Si and n‐Si/i‐BaSi₂/p‐Si thin film solar cells are investigated by solving the charge transport equations with optical generations. The diffusion current densities of free electron and hole are calculated first. Then the drift current density in the depletion regions is obtained. The total current density is the sum of diffusion and drift current densities. The conversion efficiencies are obtained from the calculated I‐V curves. The optimum conversion efficiency of n‐Si/i‐βFeSi₂/p‐Si thin film solar cell is 27.8% and that of n‐Si/i‐BaSi₂/p‐Si thin film solar cell is 30.4%, both are larger than that of Si n‐i‐p solar cell (η is 20.6%). These results are consistent with their absorption spectrum. The calculated conversion efficiency of Si n‐i‐p solar cell is consistent with the reported researches. Therefore, these calculation results are valid in this work.