Reaction and growth of Yb/Hg1−xCdxTe(110) interfaces

Abstract

Detailed synchrotron radiation photoemission studies of Yb/Hg1−xCdxTe junctions as a function of Yb coverage were performed at room temperature. Photoemission from physisorbed xenon after cooling the sample to 35 K was also used to examine the local overlayer work function and the development of interface morphology. For Yb coverages less than 6 Å, the data provide evidence for the lateral growth of islands consisting of Yb-Te reaction products involving divalent Yb, and an associated Hg depletion within an 18-Å-thick near-surface layer. Upon island coalescence at an Yb coverage of 6 Å, the formation of a metallic Yb-rich layer at the surface is observed. This layer traps Hg atoms diffusing across the interface through the formation of an Yb-Hg alloy, and is responsible for the nonmonotonic behavior of the Hg interface concentration as a function of Yb coverage.

Electrical properties of In/Yb/n-Hg1 ? x Cd x Te contacts

“…Raisanen et al [5] have shown that at coverages of > 0.6 nm of Yb, the Yb/Hgl_~CdxTe interface comprised a continuous Yb-Hg alloyed layer on top of a continuous Yb-Te reacted layer. The measurements of 9c and R~ k indicate that these reaction products were of comparatively low resistivity, with only marginal effects of Yb layer thickness on the electrical properties of the interface.…”

“…The localized change in Hg~_~Cd~Te composition and accompanying inward diffusion of the metallization can then act as a potential source of device degradation. Barrier layers of the rare-earth metals Sm and Yb have been shown to reduce the inward diffusion of In while effectively maintaining the stoichiometry at the In/Hg z _~Cd~Te interface I- 4,5]. These beneficial effects have been attributed to the greater thermodynamic stability of the rare-earth/Hgl_~Cd~Te compounds than the In-Te reaction products [4,5].…”

“…Barrier layers of the rare-earth metals Sm and Yb have been shown to reduce the inward diffusion of In while effectively maintaining the stoichiometry at the In/Hg z _~Cd~Te interface I- 4,5]. These beneficial effects have been attributed to the greater thermodynamic stability of the rare-earth/Hgl_~Cd~Te compounds than the In-Te reaction products [4,5]. The present work reports for the first time on measurements of the electrical properties (specific contact resistance, p~, and modified sheet resistance, R~k ) of contacts to Hgt_xCd~Te which incorporate an interlayer of a rare-earth metal.…”