| Summary: | 碩士 === 義守大學 === 電子工程學系碩士班 === 97 === In this thesis, the characteristics of conventional metamorphic high-electron-mobility transistor (MHEMT) and metal-oxide-semiconductor metamorphic high-electron-mobility transistor (MOS-MHEMT) are simulated and compared. By solving the one-dimensional Poisson’s equation and Schrödinger equation with iteration method, the Fermi level, EF, and the two dimensional electron gas (2DEG) sheet density, ns, are obtained for both transistors.
Next, by solving the two-dimensional Poisson’s equation with proper boundary conditions and using analytical method for both transistors, the two-dimensional potential and electric field intensity distributions are obtained. Finally, we can compare the electric field intensities along the y-direction and x-direction for both transistors. The y-direction electric field intensities around the gate terminal of the MHEMT and the MOS-MHEMT are largest. These large y-direction electric field intensities may cause the leakage currents and the breakdown voltages. The simulation results indicate that the MOS-MHEMT structure reduces the maximum y-direction electric field intensity compared with the conventional MHEMT structure, and hence, also reduces the leakage currents and enhances the breakdown voltages. Therefore, the characteristics of two-dimensional electron transportations for both transistors can be simulated reasonably by using this model.
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