BLUESHIFTING OF INGAASP INP LASER-DIODES BY LOW-ENERGY ION-IMPLANTATION/

A new method based on low-energy implantation is presented for the fab rication of laser diodes with shifted emission wavelength. The laser d iodes are based on InGaAsP/InGaAs/InP material, with compressively str ained active layers. Low-energy implantation (18 keV As+) is used to g enerate vacancies near the surface of an incomplete laser structure, f or which the epitaxial growth was interrupted 45 nm above the active l ayers of the device. The vacancies an subsequently diffused through th e quantum wells by rapid thermal annealing. This diffusion causes a lo cal intermixing of atoms at the interfaces of the active layers, which induces an increase of the band gap energy. The implantation/anneal p rocess can be repeated several times to increase the amount of intermi xing, thereby further shifting the emission wavelength. Once this proc ess is completed, the upper optical confinement layer of the structure is overgrown using chemical beam epitaxy. Operational lasers with blu eshifts as large as 35 nm were obtained. (C) 1997 American Institute o f Physics. [S0003-6951(97)01252-7].