Shantih Spanton

Home Institution: University of Wisconsin – Eau Claire

MRSEC Faculty-Student Team, with Professor Matthew Evans

MRSEC Faculty Advisor: Chris Palmstrøm

Interfacial Reactions and Determination of Diffusion Coefficients and Activation Energies of Thin Film Mn on GaAs(100)

Initial studies involved characterization of x-situ post-growth anneals of Al(50Å)/Mn(2000Å)/GaAs(100) structures at temperatures of 200-500ºC for 1-30 hours. X-ray Diffraction data for anneals above 200ºC, showed tetragonal Mn₂As-like and MnGa-like phases.  Rutherford Backscattering spectrometry measurements indicated the formulation of a diffusion controlled Mn_0.6Ga_0.2As_0.2 reacted region.  An Er marker layer between the GaAs and Mn layers, showed Mn to be the diffusive species.  Once the value and nature of the diffusion coefficient was established, the activation energy of the n-Ga-As reaction was calculated. Knowledge of the activation energy, and thus diffusion rates, will allow for fabrication of Mn films on GaAs of known compositions and thicknesses at specific temperatures.