Thermal stablity of heavily carbon-doped GaAs

• Main Authors: Meng , Suan Uang, Wei , Wen Shyang, Boon , Hoang Ong
• Format: Article
• Published: 2004
• Subjects: TA Engineering (General). Civil engineering (General)
• Online Access: http://library.oum.edu.my/repository/67/1/Thermal_stability.pdf; http://library.oum.edu.my/repository/67/

This paper investigates the effect of post-growth anneals (500'C-800'C) on the thermal stability of the carbondoped structures. Hall measurements reveal that the hole concentration aecreases steadily with increasing temperatures between 500'C and 800'C for all the heavily carbon-doped GaAs layer grown, which Is attributed to the formation of passivated dicarbon C-C complexes on the As sub-lattice. Ina-eases in hole mobility are observed in annealed layers due to lower carrier scattering as the room temperature hole mobility is dominated by ionized impurity scattering. The linear electro-optic (LEO) features observed in reflection anisotropy spectroscepy (RAS) in our heavily-doped samples did not show any change in width and amplitude when hole concentration decreases following anneals, presumably due to the smaller width of the depletion region than the light penetration depth. Raman spectroscopy showed no systematic variation of the LOPC line shape with carrier concentration due to heavy doping in our samples, which introduces a large damping constant. (Authors' abstract)