| Summary: | 碩士 === 中原大學 === 電子工程研究所 === 89 === III-nitrides semiconductors attract numerous attentions in the last decade, especially for the optical devices such as blue laser diodes as well as the high frequency, high power and high temperature electronic devices such as high electron mobility transistors (HEMTs). Owing to the inert chemical characteristics of III-nitrides, difficulty incurs in etching nitrides for the device fabrications. In this study, we utilize inductively coupled plasma reactive ion etching (ICP-RIE) technique to investigate plasma-induced damages and examine the feasibility of producing low damages etch surface
A systematic study of the effects of additive gas (Ar, N2, CH4), discharge composition, ICP source power and rf power on the etch rates and surface morphology has been performed. The moderate etch rate is obtained with 6 Ar/ 24 Cl2 sccm plasma composition at 600 ICP power, 200 rf power and 3 mTorr pressure. For PL characteristics, we find that Ar ion bombardment leaves a N-depleted surface and nitrogen vacancies behave as donor to contribute to the stronger donor peak observed in the near-band-edge luminescence. After Cl2 plasma etching the UV and YL peak intensity decrease that give rise to a nonradiative recombination. In Hall measurement, the results of Cl2-etched sample performed under conditions are very similar to the unetched samples. Ar plasma and thermal treatment lead to a slight recovery in electrical properties.
To investigate the plasma-induced damages, we can improve the performance of the GaN-based devices.
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