Characteristics of intermixed InGaAs/InGaAsP Multi-Quantum-Well Structure

Abstract

The intermixing of a InGaAs/InGaAsP multi-quantum-well (MQW) structure induced by SiO 2 dielectric cap layer deposition and heat treatment was investigated. Photoluminescence experiments reveal a large blue shift of the effective bandgap for the intermixed quantum well. By secondary ion mass spectroscopy, the group III and V elements of a MQW are found to interdiffuse at a similar rate after the intermixing process. An optical waveguide was fabricated using intermixed material where a propagation loss reduction of 450 dB was recorded at a wavelength close to the original bandgap wavelength.

Disordering of Quantum Structures for Optoelectronic Device Integration

“…The diffusion of defects is mainly affected by the thermal stress imposed on the semiconductor by the capping layer during annealing due to their mismatched thermal expansion coefficients (Fu et al, 2003(Fu et al, , 2002bPepin et al, 1997), as well as the diffusion mechanism, which is largely dependent on the types of stress (compressive or tensile) and the type and concentration of point defects (vacancies or interstitials) that are generated in the heterostructures during annealing. Nevertheless, SiO 2 is still found to be able to introduce large band-gap shifts in various InP-based QW systems (Lee et al, 1997;Si et al, 1998;Yeo et al, 2000). By choosing proper dielectric layers to control both the defect generation and the diffusion processes, intermixing can be either enhanced or suppressed in different material systems, making it possible to achieve spatially selective intermixing.…”

Fast Tuneable InGaAsP DBR Laser Using Quantum-Confined Stark-Effect-Induced Refractive Index Change

“…There are a few techniques that have been used to achieve QWI, such as impurity-free vacancy disordering (IFVD) [25]- [28], impurity-induced disordering (IID) [29], laserinduced disordering [30], and ion implantation [31]- [34]. In this paper, we apply shallow ion implantation of P + ions followed by thermal annealing [31], [32].…”

“…Varying the material of the top buffer layer provides yet another parameter for bandgap detuning control, because the types of defects generated in the material during implantation depend on the material composition itself. Increased bandgap blue shifts have been reported using an InGaAs cap layer, compared to an InP cap, below the SiO 2 layer in IFVD [27], [28]. In order to investigate this in the case of shallow implantation and to select the final conditions for the QCSE-tuned lasers, we performed calibration runs using only the InP or both the InGaAs and InP implantation buffer layers of the structure of Fig.…”

“…8(a) shows in more detail the bandgap detuning for samples with an InP or InGaAs cap as a function of annealing time. There have been a number of theories on how intermixing takes place in InGaAsP, and bandgap detuning has been ascribed to the interdiffusion of both group III and group V defects [27], [28], [33]. Fig.…”

Impurity-Free Vacancy Diffusion of InGaAsP/InGaAsP Multiple Quantum Well Structures Using SiH4-Dependent Dielectric Cappings

“…For this purpose, the selective area growth and regrowth by metal organic chemical vapor deposition (MOCVD) have been employed, but these methods involve complex steps of etching/regrowth and are not enough for large scale integration. 1) On the contrary, impurity-free vacancy diffusion (IFVD), which is one of QW intermixing (QWI) techniques 2,3) for the post-growth tuning of bandgap energy of QWs, is much simpler and more flexible. 4,5) SiO 2 has been typically used to promote the QWI, whereas Si 3 N 4 has been used to suppress the interdiffusion.…”