Interface chemistry study of InSb/Al2O3 stacks upon in situ post deposition annealing by synchrotron radiation photoemission spectroscopy

Abstract

The thermal stability of InSb/Al2O3 stacks has been systematically studied upon in situ post deposition annealing (PDA) at 300°C and 400°C. Atomic layer deposition (ALD) of Al2O3 (∼3nm) has been grown on the native oxide and the HCl aqueous solution treated InSb (100) at 200°C. The interface chemistry, elemental diffusion as well as elemental desorption are characterized by synchrotron radiation photoemission spectroscopy (SRPES) with the incident photon energy of 750, 600 and 500eV. A Math model has been proposed to calculate the depth profile for In and Sb oxides based on the analysis from different incident energies. Indium atoms have re-oxidized during ALD process, and indium oxide has been observed to diffuse into the Al2O3 film upon PDA at 300°C for the HCl pretreated sample. Indium oxide has desorbed and diffused upon PDA process for the native oxide sample. Sb oxide has been observed to desorb continuously as PDA temperature increases, for all samples. The surface has been torn up upon PDA at 400°C from the morphology characterization.