Shallow Levels Characterization in Epitaxial GaAs by Acousto-Optic Reflectance

Palabras clave

Optical refl ectance
Shallow levels. Semiconductores
Reflectancia óptica
Niveles superficiales.

Cómo citar

Torres-Cisneros, M., Ostrovskii, I., Ostrovskii, I., Burlak, G. N., Burlak, G. N., Koshevaya, S. V., Koshevaya, S. V., Guzmán-Cabrera, R., Guzmán-Cabrera, R., Aguilera-Cortés, L. A., Aguilera-Cortés, L. A., Alvarado-Méndez, E., Alvarado-Méndez, E., Andrade-Lucio, J., Andrade-Lucio, J., Rojas-Laguna, R., Rojas-Laguna, R., Estudillo-Ayala, J., Estudillo-Ayala, J., González-Barbosa, J., González-Barbosa, J., Aviña-Cervantes, J. G., Aviña-Cervantes, J. G., Cerda-Villicaña, G., Cerda-Villicaña, G., Castro-Sánchez, R., Castro-Sánchez, R., Ibarra-Manzano, O. G., & Ibarra-Manzano, O. G. (2005). Shallow Levels Characterization in Epitaxial GaAs by Acousto-Optic Reflectance. Acta Universitaria, 15(2), 42–49.


Optical spectra of light reflection are detected under an influence of ultrasonic wave (UW)on a GaAs wafer. The differential spectrum is calculated as a difference between those taken under UW and without that influence on a sample. This acousto-optic differential reflectance(AODR) spectrum contains some bands that represent the energetic levels of the shallow centers in a sample. A physical basis of this technique is related to a perturbation of local states by UW. Here, a method is developed for characterization of local states at the surfaces and interfaces in crystals and low-dimensional epitaxial structures based on microelectronics materials. A theoretical model is presented to explain AODR spectra. Also, experiments using epitaxial GaAs structures doped by Te were made. Finally, theoretical and experimental results show that acousto-optic reflectance is an effective tool for characterization of shallow trapping centers in epitaxial semiconductor structures.