A simple one-step focused ion beam milling technique was used to fabricate a Fresnel microlens array on the backside of sapphire substrate of a gallium nitride blue light emitting diode. The optical output power from the flip-chip gallium nitride blue light emitting diode is enhanced to about 1.68 times at the injection current of 20mA. The spatial light distribution from the backside of flip-chip gallium nitride blue light emitting diode with a Fresnel microlens array shows a uniform and stronger light emission.

No abstract

Gas-assisted focused ion beam etching is a very useful extension of the focused ion beam technique. In this study, gas-assisted focused ion beam etching is performed on indium-tin oxide (ITO) films using the halide gases xenon difluoride and iodine. The results from this study show that higher etching rates of ITO films may be obtained using xenon difluoride gas at a short beam dwelling time and a negative beam overlap percentage. They also show that gas-assisted focused ion beam etching has several advantages over physical sputtering in focused ion beam milling: increase in etching rate, minimization of redeposition on sidewalls, and minimization of ion implantation in samples.

This work investigates the electrical yield improvement by backgrinding process on DRAM backside with different wafer grinding technologies. The level of damage present in wafer backside subjected to different grinding technology is characterized. By comparing TEM analysis of strain layer and electrical testing result from samples that had undergone different backgrinding technologies, the most effective suitable processing conditions for the purpose of DRAM yield improvement were determined.

By using iodine gas-assisted focused ion beam etching, a gallium nitride light-emitting diode with wave-patterned sidewalls and a microlens array on a p-GaN layer was successfully fabricated without an additional lithography process. The gallium nitride light-emitting diode after gas-assisted focused ion beam etching on the sidewalls and p-GaN layer shows 24% enhancement from the sidewalls and 53% from the top surface in optical output power with an operating voltage increase of 0.06 V at 20 mA.