Study of AlGaAs/InxGa1-xAsHeterostructure Field-Effect Transistors Using AlGaAs/GaAs Buffer
| Autor: | Jun-Chin Huang, 黃俊欽 |
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| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 In this thesis, AlGaAs/InGaAs field-effect transistors using different indium content are fabricated. Furthermore, the □-doped layer effect on the device characteristics has been studied. A superlattice buffer inserted between channel and substrate for preventing electrons inject into substrate, resulting in improving carrier confinement in the channel and improving saturation and pinch-off characteristics, is studied. At high temperature, good saturation and pinch-off characteristics are observed. In addition, we use delta-doped supply carrier layer to enhance carrier concentration in the channel and to increase current density and extrinsic transconductance. The experimental results show higher carrier mobility, extrinsic transconductance, and cut-off frequency can be obtained by using higher indium composition. By using wet etching of the Schottky layer, the device breakdown characteristics can be observed. The results show that the thin Schottky layer can improve the pinch-off characteristic and extrinsic transconductance obviously. The temperature-dependent characteristics of AlGaAs/InGaAs heterostructure field-effect transistors have also been studied. The current density and extrinsic transconductance decrease with increasing temperature.We also measure microwave, power, and noise characteristics of AlGaAs/InGaAs heterostructure field-effect transistors. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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