| Summary: | 碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 96 === In this thesis, InAlAs/InGaAs/GaAs metamorphic high electron mobility transistors (MHEMTs) grown by molecular beam epitaxy (MBE) system have been fabricated and investigated. Some reports have illustrated that high energy physical vacuum depositions easily cause the thermal damage. Fermi-level is almost pinned at constant value instead of varied with different metal work functions. Result in lower Schottky barrier height of the devices. In order to eliminate Fermi-level pinning effect, electroless plated technology is employed to deposit gate metal to obtain well-behaved Schottky contact interface.
In order to investigate how electroless plated metal film influent the device, some tests and analysis to the metal film are demonstrated, including surface roughness analysis, grain size, thickness and resistivity measurement, and annealing and adhesion tests.
Finally, the characteristics of the devices with electroless plating and conventional thermal evaporation, including DC and microwave performance are compared. At room temperature, the device with electroless plating exhibits better DC performance but apparent temperature degradation rate with temperature increasing from 300K to 420K. In addition, the device with thermal evaporation still exhibits superior microwave performance.
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