Electronic properties and modeling of lattice-mismatched and regrown GaAs interfaces prepared by metalorganic vapor phase epitaxy

In order to study and model non-ideal semiconductor-semiconductor interfaces, three kinds of GaAs interfaces, i.e., (i) a slightly mismatched InGaAs GaAs interface, (ii) a highly mismatched GaAs InP interface and (iii) an air-exposed GaAs GaAs interface, were prepared by MOVPE. Their electronic properties were studied through measurements of C-V characteristics, carrier concentration profiles, DLTS spectra and I-V characteristics. By a novel interpretation of C-V characteristics and DLTS spectra, all the experimental results were explained consistently by a common model involving a U-shaped interface state continuum. The origin of the interface state continuum is explained by the disorder induced gap state (DIGS) model recently proposed for insulator-semiconductor and metal-semiconductor interfaces. This model seems to serve as a universal model for non-ideal S-S interfaces.