| Summary: | 碩士 === 國立成功大學 === 電機工程學系 === 88 === In this dissertation, investigation of etching, ohmic contacts, and oxide layers on n-GaN is our main work. We perform the etching of n-GaN by using KOH solution and Xenon RC-500B UV lamp illumination, named photo-enhanced chemical etching (PEC) method. We have discussed the effects of KOH concentration and light intensity on etching rates. We also find that the etching method offers highly anisotropic etching profile and high etching rates (45nm/min). In addition, we choose two kinds of Ti/Al (25/100nm) and Ti/Al/Au (25/100/100nm) contacts to form ohmic. After annealing, the specific contact resistances of Ti/Al and Ti/Al/Au contacts are 4.8 x 10E-4 Ω-㎝2 and 2.85 x10E-5Ω-㎝2. Finally, we have successfully deposited SiO2 films on GaN by using liquid phase deposition (LPD) method. The deposition rate of LPD method on GaN is up to 500A. And the electrical property including leakage current density and breakdown electrical field of the oxide layers can be obtained from the MOS structure. The leakage current density is about 10-5 A/cm2 while the electrical field is 1MV/cm, and the breakdown electrical field is over 4 MV/cm.
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