Real-time investigation of In surface segregation in chemical beam epitaxy of In0.5Ga0.5P on GaAs (001)

Abstract

Surface segregation processes during the growth of Ga0.5In0.5P/GaAs heterostructures by chemical beam epitaxy have been investigated in real time using reflection high-energy electron diffraction (RHEED). It is shown that In segregation occurs at both GaInP on GaAs and GaAs on GaInP interfaces. Resulting composition profiles are deduced from the RHEED data.

Differences between GaAs/GaInP and GaAs/AlInP interfaces grown by movpe revealed by depth profiling and angle-resolved X-ray photoelectron spectroscopies

“…It thus means that, after GalnP and AHnP layer growth, the In carry-over effect takes place and In atoms tend to segregate at the surface, in such way that they will likely incorporate into the GaAs outer layer. This is a well-known phenomenon described by several authors for the interface GaAs/GalnP [4, 6,22,23]. According to our results, In atoms in the GaAs/AllnP interface would exhibit the same behavior.…”

“…A rough estimation of the interface widths revealed rather large values: ~26nm for the GaAs/GalnP interface and ~32 nm for the GaAs/AllnP interface. Such high values account for intrinsic interface features, like In segregation, that can spread up to 10 monolayers across the interface [22], but also for sputtering effects like preferential sputtering that would enlarge the interface width. The way the concentration of the top layer constituents (Ga and As) diminishes across the interface is not linear.…”

Indium surface segregation in AlSb and GaSb

“…Moreover, in the case of GaSb, R becomes saturated above 520 C. This means that we are closer to the equilibrium situation for GaSb than for AlSb, which is not surprising when considering the difference in binding energy [26]; (iii) the values obtained here agree well with reported R values for other In containing material systems [3,5,7,9], although for the present material system, the R value remains high even at low temperature (T ¼ 400 C), in particular for GaSb. As a consequence, significant indium surface segregation effects are expected in a wide temperature range for all structures involving Al(Ga)Sb/InAs(Sb) interfaces.…”

“…It is now well established that In surface segregation prevents the formation of abrupt interfaces in these heterostructures. However, despite the drastic effect of this intrinsic phenomenon on the actual potential profiles at quantumwell interfaces, only scarce results are available for other In containing III-V heterostructures such as (Ga,In)As/InP [8], (Ga,In)P/GaAs [9] and In(-As,Sb)/(Al,Ga)Sb [10,11], although they are currently used for quantum device fabrication. The latter heterostructure is in this context prototypical: a lot of work has been devoted to the influence of the bonding (InSb-or (Al,Ga)As-like) at the interfaces on the electronic and optical properties [12][13][14], but little attention has been paid to In surface segregation effects at (Al,Ga)Sb on In(-As,Sb) interface.…”

Metalorganic chemical vapor deposition growth and characterization of InGaP/GaAs superlattices

“…Indium surface segregation has been reported in several material systems, such as grown InGaP lattice-matched on GaAs, InGaAs on GaAs, etc. 11,12 Due to In surface segregation, the interface is no longer abrupt and there will be a gradual increase in the In alloy composition when growing InGaP on GaAs and also a gradual decrease in the unintentional In incorporation in GaAs when growing GaAs on InGaP. Note that this is different from the In carry-over and In memory effects, which can be minimized through controlling the interruption during the growth at interfaces.…”