| Summary: | 碩士 === 國立中興大學 === 電機工程學系所 === 97 === In the essay, we have researched many etched method of GaN. We chose the way of electrodeless photoelectrochemical etching with a chopped UV source to conduct the etching frame design and experiment, we hope we can apply this method on large area GaN chips making cylinder array LEDs.
From the experiment showing, using GaN proceed to etch with electrodeless photoelectrochemical etching with a chopped UV source can improve the root-mean-square of the sample surface when the laser pulse’s frequence is higher. In making the electrochemical etching experiment, we found at the better root-mean-square of the sample surface in etching when we increase KOH concentration and delay the time under the environment of adding photoassisted anodic and etched solution.
In the end, we focus on the GaN’s sample surface before and after using electrodeless photoelectrochemical etching with a chopped UV source by plating electrode on the sample surface and measure I-V curves. We found the pure GaN sample surface’s I-V curves present Schottky contact, but after etched GaN sample surface’s I-V curves present Ohm contact. After longer etching time, GaN’s sample surface can produce smaller contact resistance.
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