| Summary: | 碩士 === 國立東華大學 === 材料科學與工程學系 === 96 === In this thesis, the high-electron mobility transistors (HEMTs) and heterojunction bipolar transistors (HBTs) are grown by metalorganic chemical-vapor deposition (MOCVD). These devices have been widely used in wireless communication.
Selective wet etching and nonselective wet etching are adopted in this investigation. The optimal etching solutions are selected to obtain the good surface roughness. Recently, we have demonstrated that HEMTs and HBTs have improved performance after passivation, including smaller leakage current, enhanced barrier height, and improved extrinsic transconductance for HEMTs (or improved current gain for HBTs). Electron microscopy (FESEM), atomic force microscopy (AFM), Auger energy spectrum (AES) and electron spectroscopy for chemical analysis (ESCA) are used. Auger energy spectrum and secondary ion mass spectrometer (SIMS) is for depth analysis. Furthermore, photoluminescence spectrum (PL) analysis is used for optical measurement.
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