Defect density in ZnSe pseudomorphic layers grown by molecular beam epitaxy on to various GaAs buffer layers

• Published in: Journal of crystal growth Vol. 192; no. 1; pp. 102 - 108
• Main Authors: Bousquet, V, Tournié, E, Faurie, J.-P
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.1998; Elsevier
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defect density; Defects and impurities: doping, implantation, distribution, concentration, etc; Exact sciences and technology; Materials science; MBE; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; ZnSe; MBE; Defect density; 61.72.F; 81.15.H; 68.55.Jk; ZnSe; Buffer layer; Gallium arsenides; Inorganic compounds; Crystal defect density; Migration; Transition element compounds; Binary compounds; Zinc selenides; Crystal growth from vapors; Experimental study; Surface termination; II-VI semiconductors; Etch pits; Pseudomorphic growth; Molecular beam epitaxy; Heterojunctions
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(98)00447-3

We have investigated the influence of both the GaAs surface stoichiometry and the nucleation procedure on the defect density in ZnSe pseudomorphic layer. We have shown that the use of migration enhanced epitaxy (MEE) at low temperature in the first steps of the growth decreases the defect density by two orders of magnitude. For a ZnSe layer grown by conventional MBE on a (2×4)-GaAs surface the etch pit density (EPD) is equal to 5×10 6 cm −2 but it reaches 5×10 4 cm −2 when MEE is used at the beginning of the growth. The same behavior is reported for the growth on a c(4×4)-GaAs surface but the use of MEE decreases only the density down to 4×10 5 cm −2. Atomic force microscopy shows that the surface roughness and morphology are also improved. We have tried to incorporate a thin BeTe layer between the GaAs buffer and the ZnSe layer. The ZnSe growth start is two-dimensional but the defect density is only of 8×10 5 cm −2.