Fabrication of Optoelectronic Integrated Circuits Using Quantum Well Intermixing

Electrical engineering, Condensed matter physics

Ooi, Boon Siew

University:University of Glasgow

关键词: Electrical engineering, Condensed matter physics;   

Others  :  http://theses.gla.ac.uk/75450/1/13831538.pdf

来源: University of Glasgow

【 摘 要 】

The effects of C2F6 overetching on subsequent SiCl4 etching of GaAs/AlGaAs structures are investigated. This study is important for the fabrication of photonic devices in the later part of this project. A new reactive ion etching (RIE) damage detection technique, using a quantum well intermixing (QWI) probe, was developed and was used to investigate the RIE processes used in device fabrication. Using this damage detection technique, both the depth of RIE damage and propagation depth of the point defects generated by RIE can be probed and profiled. A new QWI process, called plasma induced layer intermixing, has been developed. Bandgap tuned oxide stripe lasers have been fabricated. The quality of the material was found to be maintained after intermixing using this technique. Oxide stripe extended cavity lasers have also been demonstrated. Losses as low as 18.1 dB cm-1 have been measured in lasers with 500 gm long extended cavity sections intermixed using this new QWI process. The diffusion and the intermixing mechanisms of fluorine and boron impurity induced disordering (IID) are investigated. Diffusion models and intermixing mechanisms for these species are proposed. A transmission electron microscope (TEM) was used to study the residual damage induced by these species in GaAs/AlGaAs structures. Comparing these two species, fluorine was found to be a better candidate to be used in neutral BD since it results in less residual damage, lower loss, and larger degree of intermixing. Low loss rib waveguides have been fabricated using fluorine IID and the propagation loss was found to be reduced to as low as 20 dB cm-1 at the lasing wavelength. A new technique, called selective intermixing in selected area (SISA), has been developed to control the degree of intermixing in selected areas. Five distinguishable wavelengths (861 nm, 855 nm, 848 nm, 844 nm and 840 nm) have been observed from bandgap tuned lasers fabricated on a single chip intermixed using this technique.