1.3μmInGaAsP/InP发光管退化的研究

研究了InGaAsP/InP双异质结发光管在老化,存储过程中的退化现象及其影响因素.有快慢二种退化模式,正向I-V特性变坏是产生突然退化的最主要因素,焊料的润湿不良是导致器件退化的原因之一;在70℃,85℃老化及存储过程中,个别器件有源区内有DSD产生并长大,这并不是引起突然退化的原因.

STUDY OF THE DEGRADATION CHARACTERISTICS FOR THE InGaAsP/InP DH LEDs

The abrupt degradation characteristics of the InGaAsP/InP DH LEDs were studied. The InGaAsP/InP DH wafers were grown by LPE technique. It consisted of three or four layers. The First n-InP layer was a 5-8μm thick buffer layer doped with Sn or Te. The second one was an undoped active layer approximately 1-2μm thick. The third was confining layer of p-InP (2-3μm thick) doped with Zn. The last was Zn doped contact layer. The concentration in the active layer was measured electrochemically with C-V methode. The devices are smallarea, surface emitting diodes.The degradation characteristics of the InGaAsP/InP DH LEDs were investigated at room temperature, 70 and 85℃ and with and without injetc current respectively. The experiment was carried out in air and one hundred devices fabricated from different wafers were used.When aging dark defects in the LEDs are observed with an infrared line scanner.The effects of the inject current, environment temperature,active layer concentration and solder on the degradation characteristics of the devices were investigated. The results showed that the forward anomalous I-V characteristics (i.e.Vf/Vf0≈0,V/V0<1) were directly responsible for the abrupt degradation.The EL pattern is homogeneous even the LEDs operate for 1000hrs at a current of 100mA at 85℃.The DSD''s are sometimes generated in the emitting area when aging at 70 and 85℃ for over lOOOhrs, but they are not the reason for the abrupt degradation.