Calibration of Silicon- and Tellurium- Doped Gallium Arsenide Using the Hall Effect

Molecular Beam Epitaxy (MBE) provides a method for growing semiconductor crystals whose electrical properties may be fine-tuned through the addition of impurity (dopant) atoms. The addition of impurity atoms, such as tellurium or silicon, to gallium arsenide allows us to increase its electrical conductivity, which is critical for the production of electronic devices. Characterization using the Hall Effect and van der Pauw technique determines the electrical characteristics of these materials, including mobility and carrier (e.g. electron) concentration. It is the goal of this project to optimize both the MBE growth conditions and characterization methods and to produce a data set identifying the relationship between the temperature of the dopant element during deposition and the resulting carrier concentration. These values were found to have a linear Arrhenius relationship for silicon between 1025 – 1250°C, producing a carrier concentration range of 9.37x1015– 6.14x1018cm-3and a mobility range of 1171 – 4951 cm2/Vs, and for tellurium between the temperatures of 500 – 625°C with a carrier concentration range of 5.12x1016– 1.01x1019cm-3and a mobility range of 1284 – 4632 cm2/Vs. These silicon and tellurium dopant calibrations are essential for yielding reproducible materials and serves as the foundation for continued research into doped semiconductor materials