980nm大功率半导体激光器的MOCVD外延生长条件优化

Optimization of MOCVD Growth for 980nm High-power Laser Diodes

摘要:

为了对980nm大功率半导体激光器的波导层和有源层外延材料进行快速表征,设计了相应的双异质结（DH）结构和量子阱（QW）结构,并在不同条件下进行了MOCVD外延生长,通过室温荧光谱测试分析,得到Al0.1Ga0.9As波导层的最佳生长温度为675℃,InGaAs QW的最佳长温度为575℃。为了兼顾波导层需高温生长和QW层需低温生长的需求,提出在InGaAs QW附近引入Al0.1Ga0.9As薄间隔层的变温停顿生长方法,通过优化间隔层的厚度,InGaAs QW在室温下的PL谱的峰值半高宽只有23meV。基于优化的外延工艺参数,进行了980nm大功率半导体激光器的外延生长,并制备了腔长4mm、条宽95μm的脊形器件。结果显示,在没有采取任何主动散热情况下,器件在30A注入电流下仍未出现腔面灾变损伤,输出功率达到23.6W。

Abstract:

For the purpose of rapidly characterizing the quality of waveguide layers and active layers for high power laser diodes emitting at 980nm, the structures of heterostructrue (DH) and quantum well (QW) were designed and grown by metalorganic chemical vapor deposition (MOCVD) under different conditions. Through test and analysis of Photoluminescence (PL) spectra at room temperature (RT), it is found that the optimal growth temperature of InGaAs QW and Al0.1Ga0.9As DH is 575 and 675℃, respectively. For the purpose of balancing high growth temperature of waveguide layers and low growth temperature of QW, a method of introducing thin Al0.1Ga0.9As spacers in both sides of QW and growth stopping in the transition of different temperatures was proposed. By optimizing the thickness of spacer layers, the full width at half maximum (FWHM) of InGaAs QW was only 23meV. Based on the optimized epitaxial parameters, high power laser diodes were grown by MOCVD, and then a ridge type device of 95μm-strip-width and 4mm-cavity-length was fabricated. Due to the insurance of the epitaxial material quality, the output power can reach 23.6W at 30A without any catastrophic optical damage (COD), while no active cooling measures were taken.