Study of thermal stability of distributed Bragg reflectors based on epitaxial rare-earth oxide and silicon heterostructures

Abstract

Thermal stability of rare-earth oxide/silicon multilayer heterostructure-based distributed Bragg reflectors under typical metal organic chemical vapor deposition process temperatures with an ambience of typical process gases was studied. Gadolinium oxide or erbium oxide based two period (¼λ oxide, ¾λSi) blue light (λ = 450 nm) mirrors with Si layer on the top were annealed in H2, N2, and H2 + NH3 gases for 20 min at 1015 °C in a metal organic chemical vapor deposition chamber. Changes in the structure were analyzed using x-ray diffraction and transmission electron microscopy. Reflectivity measurements were used for evaluation of optical properties of the reflectors before and after annealing. Chemical reaction between gadolinium oxide and silicon are revealed by reduction of reflectivity of Gd2O3/Si based distributed Bragg's reflector and GdSi2-x attributed peaks detected by x-ray diffraction. No major changes were detected in the Er2O3/Si heterostructure-based reflector, indicating good chemical and crystal stability of erbium oxide.