Ion beam mixing characteristics of MOCVD grown InGaAs/GaAs superlattices

The ion beam mixing behavior of InGaAs/GaAs strained layer superlattice structures grown by metalorganic chemical vapor deposition was studied using secondary ion mass spectroscopy and Rutherford backscattering channeling. The fluence dependence of intermixing by MeV Kr⁺ irradiation has been investigated. Significant intermixing occurs for fluences much lower than for similar intermixing in other superlattice systems (i.e. ALAs/GaAs). The intermixing exhibits no temperature dependence for fluences of 2 x 10¹⁵ to 5 x 10¹⁵ cm⁻² which sharply contrasts with the behavior of the AlAs/GaAs superlattice system which shows a strong temperature dependence, including a miscibility gap, in the temperature range 523 to 973K. Samples irradiated at 573K retain a high degree of crystallinity when compared to lower temperature irradiations indicating that the InGaAs/GaAs superlattice can be disordered and still retain crystallinity.