| Summary: | 碩士 === 國立交通大學 === 光電工程所 === 88 === We study the process of GaN material including ohmic contact on p-GaN and Eximer laser etching of GaN. In ohmic contact, alloy consisted of Ni/Pd/Au film deposited on p-type GaN followed by heat treatment in oxygen condition. A good ohmic characteristic and specific contact resistance as low as 1.1 ×10-4Ω-cm2 was obtained at 550℃,5min. Another approach to achieving low-resistance ohmic contact is carrier concentration improvement of p-GaN by Be-implanted . A minimum ρc =4.5×10-4Ω-cm2 and perfect ohmic was obtained by Ni/Pd/Au contact without any heat treatment.
In Eximer laser processing, both pulse energy and numbers of pulse of KrF laser were varied to etch the GaN film. By changing the pulsed energy at constant pulse energy, ablation of GaN surface was observed at threshold fluence of 0.3 J/cm2. A high etching rate of 82 nm/sec was obtained at fixed laser fluence of 0.3 J/cm2. Finally, we successfully separate GaN from GaN/sapphire structures using a KrF laser pulse of 1.0 J/cm2.
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