Multiple-angle-of-incidence ellipsometry for GaAsGaPAs superlattices

✍ Scribed by NL Dmitruk; OS Gorea; TA Mikhailik; VR Romaniuk; LA Zabashta

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 348 KB
• Volume: 50
• Category: Article
• ISSN: 0042-207X
• DOI: 10.1016/s0042-207x(98)00078-5

✦ Synopsis

In this paper we present results of multiple-angle-of-incidence (MAI) ellipsometry for strained GaAs/GaP x As 1-x superlattices (SL) with the composition x ¼ 0.4 and with different layer thickness in the range of 8-80 nm. SLs have been grown on the GaAs (100) substrates by chemical vapour deposition. The geometrical parameters of SLs have been determined by X-ray diffraction patterns. From MAI measurements the thickness and optical constants of SL films have been calculated by solving inverse ellipsometric problem. The latter was solved by using Tichonov's regularization algorithm. The anisotropic film model of SL and capping isotropic layer were taken into account at solving. The optical constants obtained together with the full thickness of SL have been related to the SL microstructure using an effective medium approximation. These results are compared with ones obtained by far-infrared reflection spectroscopy in the ''reststrahlen'' band region. The quality of SLs in connection with technology of thin films growth are discussed.