Degradation mechanisms in high power InGaN semiconductor lasers investigated by electrical, optical, spectral and C-DLTS measurements

• Published in: Microelectronics and reliability Vol. 114; p. 113786
• Main Authors: Piva, F., De Santi, C., Buffolo, M., Taffarel, M., Meneghesso, G., Zanoni, E., Meneghini, M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2020
• ISSN: 0026-2714; 1872-941X
• DOI: 10.1016/j.microrel.2020.113786

The aim of this work is to study the degradation processes in high power InGaN semiconductor lasers, by means of electrical, optical, spectral and capacitance deep-level transient spectroscopy measurements. The devices were submitted to two different stress experiments, (i) a constant current stress at 1.5 A and 45 °C, and (ii) a temperature/bias step stress at 1 A and increasing temperature. Results demonstrated: (i) two different mechanisms that change the drive voltage, one due to the activation of Mg and one ascribed to the generation of point defects; (ii) a parasitic peak is present in the emission spectra, ascribed to the recombination in a second quantum well (QW); (iii) redistribution of charge takes place during the temperature step stress. •In the constant current stress, degradation consists in a decrease in optical power below the threshold•Constant current stress test induces changing in the drive voltage below the turn on and in the emission spectra•Different behavior of the sample in the current step stress•Current step stress test induces a redistribution of the charge in the device•C-DLTS measurements confirm the presence of different type of defects