| Summary: | 碩士 === 國立中央大學 === 電機工程學系 === 106 === This thesis aims at fabrication and characterization of high frequency characterisitcs of AlInN/AlN/GaN high electron mobility transistors (HEMTs). In this work, 0.4 μm Schottky-gate HEMTs have been fabricated on epiwafers grown by metal-organic chemical vapor deposition on Si substrates. The devices exhibit Idss of 713 mA/mm, peak transconductance of 300 mS/mm, and breakdown voltage of 117 V. High frequency measurements indicate that the devices have current gain cut-off frequency of 48.9 GHz and power gain cut-off frequency of 57.3 GHz. These results are comparable or better than the best reported results in the literature.
We have also constructed a small signal circuit model for the devices fabricated on epiwafers grown by trimethylgallium (TMG) and triethylgallium (TEG). Based on the thickness of the epitaxial layers, dielectric constant and device layout, a new cold FET model is established for parasitic capacitance. This helps to accurately extract the small signal circuit parameters of the devices as indicated by the good match between the simulated and measured results. This parameter extraction method has been used to compare the difference between devices grown by TMG and TEG.
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