고출력 SLD 제작을 위한 1.55㎛ InGaAsP/InP wafer 성장에 관한 연구

Abstract

SLDs are known as proper optical sources for the applications related to the optical measurements, since their properties are intermediate between those of the LEDs and LDs. And it is expected that the demand of SLDs will be largely increased with the progress of optical industries.

This study is a fundamental work for the fabrication of high-performance SLDs by LPE system and the aim is to grow InGaAsP/InP wafers for 1.55㎛ SLDs.

Before the wafer growth, both structures were approximated to five-layer slab waveguides then analyzed theoretically using the wave equations for the transverse mode and effective-index approximation in order to obtain the optimized conditions for the growth of high-efficiency epi-wafers.

On the basis of the results and the theory of InGaAsP/InP growth by LPE, the thickness of each epi-layer and growth variables were determined, then each epi-wafer was grown by vertical LPE system handmade in this laboratory.

In the growth of SCH-MQW wafers, it was confirmed that epi-layers were grown thickly compared with the result of theoretical analysis at present stage, thus it appeared that more research was to be carried out in the future in order to obtain InGaAsP epi-layers enough thin to have quantum size effect.

In the growth of SC-DH wafers with 1.3㎛ InGaAsP SC layers, we obtained the thickness nearly coincident with the results of theoretical analysis and good surface quality, when the growth temperature was 630℃, the cooling rate was 0.8℃/min, and single crystal InP was used as InP solute for two-phase method. It was also confirmed that the lasing wavelength of the wafer was 1.55㎛ as a result of the measurement of photoluminescence.

Therefore, It could be confirmed that the growth of 1.55㎛ InGaAsP/InP epi-wafers for SLDs was possible by LPE system.

It is also expected that the fabrication of high-performance SLDs will be possible if the optimized PBH structure is designed using this wafer and then the proper methods for reflectivity control are applied.