Abstract
There are more and more applications based on GaN related optoelectronics and plastic fiber communication happens to be one of the potentials. This experiment makes use of GaN material to make out heterojunction bipolar transistors mainly. Before making the device actually, we have tried the wet etching of the GaN at first, hope the wet etching technology that etches can be applied to the making of the real device. Finally, we made the device actually and analyzed and discussed by secondary ion mass spectrometer and semiconductor parameter analyzer. Wet etching focused on applying UV-LEDs to n-type GaN PhotoElectroChemical (PEC) wet etching. In our experiment, KOH solutions with PH values lying between 11.0 and 14.0 are used as etchants. We also examined both Ti/Au 30nm/300nm andTi/Al/Ni/Au 25nm/125nm/45nm/55nmΑcontacts as wet etchingmasks. Finally, we have demonstrated that UV-LED made from Nichia with 365 nm peak wavelength can be used to etch the n-GaN and stop on top of the p-GaN in a PH=14.0 KOH solution and the etching depth is around 1.4μm. The wafer were grown by Microwave & Optoelectronic Devices Laboratory,Prof. Jen-Inn Chyi, ncu, and all the fabrication were in Compound Semiconductors Lab, ncu .We got a lot of necessary condition data in the experiment .Finally, we got a very important parameter, current gain, 1.21 by using semiconductor parameter analyzer HP4156A.