Demonstration of genuine surface inversion for the p/n-In0.3Ga0.7Sb-Al2O3 MOS system with in situ H2 plasma cleaning

The results of an investigation into the impact of in situ H2 plasma exposure on the electrical properties of the p/n-In0.3 Ga0.7 Sb-Al2O3 interface are presented. Samples were processed using a clustered inductively coupled plasma reactive ion etching and atomic layer deposition tool. Metal oxide semiconductor capacitors were fabricated subsequent to H2 plasma processing and Al2O3 deposition, and the corresponding capacitance-voltage and conductance-voltage measurements were analyzed quantitatively via the simulation of an equivalent circuit model. Interface state ( D it) and border trap ( N bt) densities were extracted for samples subjected to the optimal process, with a minimum Dit of 1.73 × 10 12 eV−1 cm−2 located at ∼110 meV below the conduction band edge and peak N bt approximately aligned with the valence and conduction band edges of 3 × 10 19 cm−3 and 6.5 × 10 19 cm−3, respectively. Analysis of the inversion response in terms of the extraction of the activation energy of minority carriers in inversion (p-type) and the observation of characteristics that pertain to minority carriers being supplied from an external inversion region (n-type) unequivocally demonstrate that the Fermi level is unpinned and that genuine surface inversion is observed for both doping polarities.