Effect of Surface Treatment on the Charge Density at the Interface between GdHgTe Epitaxial Films and Al$${}_{\mathbf{2}}$$O$${}_{\mathbf{3}}$$ Grown by Atomic Layer Deposition

Abstract

The effect of the different surface treatment of Hg $${}_{1-x}$$ Cd $${}_{x}$$ Te (CMT) films before the atomic layer deposition of Al $${}_{2}$$ O $${}_{3}$$ dielectric on the charge at the dielectric–semiconductor interface has been studied. Metal–dielectric–semiconductor (MDS) structures with different surface treatment before the deposition of a dielectric have been manufactured. The capacitance–voltage characteristics of CMT based MDS structures have been measured alongside with the surface charge density. The surface charge is non-uniformly distributed over the surface of films with $$x=0.22$$ and a natural oxide layer and equal to $$(0.8{-}1.8)\times 10^{-8}$$ C/cm $${}^{2}$$ , and this may lead to the inversion of the surface conductivity type. The exposure of these CMT structures in mercury vapor at room temperature leads to the formation of a negative charge within a range of $$-(0.4{-}1.6)\times 10^{-8}$$ C/cm $${}^{2}$$ .