Influence of UDMHy on GaAs (0 0 1) surface reconstruction before and during growth of Ga(NAs) by MOVPE

• Published in: Applied surface science Vol. 458; pp. 512 - 516
• Main Authors: Maßmeyer, O., Sterzer, E., Nattermann, L., Stolz, W., Volz, K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2018
• Subjects: Characterization; Metalorganic vapor phase epitaxy; Nitrides; Reflectance anisotropy spectroscopy; Semiconducting III–V materials; Surface structure; Characterization; Nitrides; Reflectance anisotropy spectroscopy; Metalorganic vapor phase epitaxy; Surface structure; Semiconducting III–V materials
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.07.098

[Display omitted] •In situ characterization of dilute nitrides during growth by MOVPE.•Dilute nitrides exhibit a more Ga or N rich (2 × 6)/(6 × 6) surface reconstruction.•UDMHy induces a rapid change of the surface reconstruction.•The surface reconstruction is crucial to incorporate nitrogen into GaAs. III–V semiconductors containing small amounts of Nitrogen (“dilute nitrides”) are very promising material systems for optoelectronic applications. There are many studies about growth characterization of Ga(NAs) in metalorganic vapor phase epitaxy (MOVPE), but very little is known about the nitridation process on the GaAs (0 0 1) surface and the influence of the surface reconstruction on the Nitrogen (N) incorporation. Therefore, we investigated GaAs (0 0 1) surfaces under different tertiarybutylarsine (TBAs) and 1,1-dimethylhydrazine (UDMHy) ambient conditions in MOVPE. For in situ surface characterization reflectance anisotropy spectroscopy (RAS) was used. Under sufficient TBAs stabilization the surface forms an As rich c(4 × 4)β surface reconstruction. This changes towards a more Ga rich (2 × 6)/(6 × 6)-like reconstruction if additional N is supplied. Therefore, UDMHy seems to enhance the As desorption from the surface or the surface reconstruction changes due to incorporated N. This conversion occurs rapidly within 5 s when UDMHy is supplied and was observed in a temperature range from 450 °C to 600 °C. The measured RAS spectra are then compared to the RAS spectra obtained during Ga(NAs) growth. These also exhibit a (2  ×  6)/(6  ×  6)-like surface reconstruction which seems to be necessary to incorporate a sufficient amount of N into the GaAs crystal.