Doping Technologies for Lateral Junctions in Photonic Crystal Membranes

Development of optical short-range data interconnects for photonic network-onchip applications brings the prospect of overcoming the problems related to power consumption and transmission speed of electrical counterparts. Photonic crystals constitute a highly flexible platform with rich physical phenomena, which allow miniaturization and tight integration of a wide range of devices. The focus of this work is on indium phosphide (InP) photonic crystal membranes bonded to silicon (Si) for the realization of lasers and all-optical switches based on Fano resonance. The important component is a lateral p-i-n junction in InP membrane, which is required for electrical pumping of the lasers, as well as for carrier sweepout from the Fano switches. For this purpose, doping technologies for InP have been investigated. The main part of this work has been dedicated to the extensive development and optimization of the fabrication procedure for the experimental realization of lasers and Fano switches with the lateral p-i-n junction. Various fabrication issues and the ways to solve them are described. Direct bonding of InP to Si substrate is implemented to take advantage of mature silicon industry. For n-type doping, silicon ion implantation is investigated. Optimal ion energy, dose and activation temperature are investigated, with the consideration of the effect on active material properties. The possible drawback of undesired overall p-doping and the way to avoid it are addressed. For p-type doping, zinc thermal diffusion is analyzed. A thorough study of various diffusion parameters affecting the electrical properties of p-InP is presented. The problem of diffusion-induced surface deterioration in special cases is identified and solved. Lateral redistribution for both silicon and zinc is characterized. Light emission under electrical injection has been observed, however, no lasing has been achieved due to fabrication obstacles. In the case of Fano switches, wavelength conversion has been successfully performed, with a hint on the possibility of enhancement of modulation bandwidth due to carrier sweep-out from the Fano cavity. Future opportunities for devices performance improvement are discussed.