| Summary: | 碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 93 === In this thesis, two InP-based heterostructure field-effect transistors (HFETs), grown by molecular beam epitaxy (MBE) system, have been fabricated and investigated. We evaporated platinum and gold as Schottky contact metals to obtain high-temperature performance. In addition, the highly selective succinic PH-adjusted solution is used to make recessed gate more precise and stable to increase device yield. For obtaining more power gain and bandwidth of transistors, we also fabricate sub-micron meter gate devices with resorting to deep ultraviolet (UV) photolithography. Experimentally, the devices show good DC, RF, and high-temperature characteristics. These advantages suggest that the studied devices are suitable for high-speed and high-power integrated circuit applications.
First, we study InGaAs/InAlAs/GaAs metamorphic high electron mobility transistor. With high indium content in InGaAs channel layer, we obtain good transport property. Moreover, by employing the single d-doped sheet, it not only decreases the impurity scattering, but also increases the ability of carrier confinement.
Second, we report InGaAs/InAlAs/GaAs metamorphic high electron mobility transistor with higher In mole fraction of InGaAs channel than that in first structure. Based on the use of double d-doped sheets, the current density and uniform distribution of carriers in channel layer are improved. Therefore, the device with wide drain current operation regime is obtained. In addition, due to the use of thicker Schottky layer, the gate leakage current can be decreased.
Finally, the above structures are used to fabricate as sub-micron meter gate MHEMT. We discuss the differences between these two structures. Due to the reduction of gate length, both devices show good DC and microwave performances.
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