An investigation of the growth and removal of protective antimony caps for antimonide epilayers

Optimization of MBE-grown GaSb buffer layers and surface effects of antimony stabilization flux

“…Growth of III/V compounds requires stabilization of the wafer surface with a flux of group-V material while the substrate is at elevated temperature to avoid noncongruent sublimation and consequent degradation of the surface [20][21][22]. At sufficiently low substrate temperature, group-V material condenses on wafer surfaces, a situation which is potentially useful [23], and also potentially detrimental as will be shown here.…”

“…These samples were exposed to antimony overpressure at 295 3 C for reduced amounts of time. Antimony cap layers may be easily removed by thermal [27,22] or chemical means, and are often used as a passivation layer to prevent atmospheric contamination of samples during transfer between processing chambers. Neglecting to properly remove antimony layers (or lack of awareness of their existence on a sample) prior to additional processing may be detrimental to that processing and the final device.…”

Investigations into molecular beam epitaxial growth of InAs/GaSb superlattices

“…However, if the antimony flux is present at low temperatures it is possible to grow a cap layer of elemental antimony. 37 While this cap has been purposefully employed as a means of protecting samples, 38 Interfaces between GaSb and InAs are complex. The lack of common atoms means that they can form in two ways: either GaAs-like or InSb-like.…”

High power mid-wave and long-wave infrared light emitting diodes

“…This is, however, not the case after the substrate has reached temperatures below 350 • C, at which point antimony layers may condense on the surface. Growth of antimony layers may be beneficial for wafer encapsulation or passivation when transferring the wafer to a separate growth or analysis chamber requires exposure to ambient conditions[83,84]. Here it is demonstrated that antimony layer condensation may pose difficulties in device processing and testing, and thus substrate cooling should be controlled in such a fashion to halt antimony flux application before condensation occurs.Condensation of antimony on the wafer surface may be easily assessed by bothAFM and x-ray photoelectron spectroscopy (XPS).…”