Composition Control of InGaAsP Laser Structures Using In-Situ Emissivity Corrected Pyrometry During Epitaxial Growth

Abstract

Wafer temperature during metal-organic chemical vapor deposition growth strongly influences the composition, and therefore, photoluminescence wavelength of InGaAsP layers when using AsH3 and PH3 precursors. Emissivity corrected pyrometry was used to measure and control the wafer temperature during epitaxial growth of 1.5 µm InGaAsP laser structures. Control of laser structure wavelength was demonstrated using an Emcore D180 LDM reactor. Average peak wavelength for five, six wafer runs had a standard deviation of 2.1 nm indicating excellent repeatability as long as wafer temperature was identical from run to run. Composition control was further demonstrated by intentionally reducing the wafer temperature during two successive growth runs. Average peak PL wavelength increased from 1522 nm to 1530 nm by reducing RealTemp wafer temperature 2°C from 607.7°C to 605.7°C during active region growth, corresponding to a 4 nm shift of wavelength for a 1°C change.