수소기상증착법에 의한 선택성장 LED의 제작에 관한 연구

Abstract

The SAG (selective area growth) method of wide band gap semiconductor allows the production of high performance LEDs (light emitting diodes) in the green, blue and ultra-violet region. The conventional HVPE (Hydride Vapor Phase Epitaxy) have been used for the growth of a high quality thick GaN epilayer. However, it is difficult to growth of the heterostructure with multi-layers using HVPE method due to its high growth rate and complex innards.

In this study, we fabricated the SAG-GaN LED using the mixed-source HVPE method with multi-sliding boat system.

The temperature of source zone and growth zone were 900 and 1090 ℃, respectively. The n-type and p-type dopants were Si and Mg, respectively. NH3 gas used for supply nitrogen source and carrier gas was N2. The LED structure consisted of 9 layers : n-GaN/n-AlGaN/GaN/InGaN/GaN/InGaN/GaN/p-AlGaN/p-GaN. These layers were grown consecutively using multi-sliding boat. After the selective growth process, the Ni/Au and Cr/Ni/Au were deposited for transient metal and n,p electrode, respectively.

From the result of cross-sectional FESEM measurement, the total thickness of epilayers is 19.3~66 µm and growth rate is 0.7 µm/min. From the SIMS measurement, the depth of the end of Al peak was 0.6 µm and the depth of In peak was from 4.8 µm to 6.2 µm. The result of EL measurement, main peak was 437~484 nm and FWHM was 22~49 nm. The working voltage was 3.0~3.38 V and resistance was 8.6~49.48 Ω. From all these results, successfully we fabricated SAG-GaN LED by HVPE. We suggest that the HVPE method can apply to fabricate high quality LEDs.