Optical constants of (Al0.98Ga0.02)xOy native oxides
K. J. Knopp, Richard Mirin, David H. Christensen, Kristine A. Bertness, Alexana Roshko, R A. Synowicki
We report the optical constants of oxidized crystalline and low-temperature-grown (LTG) Al0.98Ga0.02As films, as determined by variable angle spectroscopic ellipsometry. Data were acquired at three angles of incidence over 240-1700nm and fit to a Cauchy dispersion function. For oxidized crystalline material, we observe a variation in the real index of 5% for layer thickness variations of 6%. We show that upon oxidation, LTG material can expand by >25% while crystalline material contracts by <2%. Atomic force microscopy analysis indicates thickness-dependent variations in the oxide microstructure. Additionally, an optical scattering loss of 1.1×10-6 is calculated based on surface roughness measurements for a thin layer of oxidized crystalline material.
, Mirin, R.
, Christensen, D.
, Bertness, K.
, Roshko, A.
and Synowicki, R.
Optical constants of (Al<sub>0.98</sub>Ga<sub>0.02</sub>)<sub>x</sub>O<sub>y</sub> native oxides, Applied Physics Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=14955
(Accessed December 1, 2023)