Formation energies and equilibrium configurations of dislocation arrays with alternating Burgers vectors in layered heterostructures.

Cubic layeredheterostructuresareindispensablefeaturesofmanyelectronicdevices;however,the latticemismatchtendstoinducedefects,e.g.dislocations.Glissile601 misfitdislocations(MDs) generallyformintheearlystageofstrainrelaxation.Duringannealing,eachrelaxing601 dislocation compensated-pair(60DCP)(withcancelingscrewandinterface-perpendicularedgecomponents)may coalesceintoa901 (pureedge)dislocation,whichisapossiblemechanismforthereductionof threadingdislocations(TDs)throughannealing.Inthispaper,wecalculatetheformationenergiesof periodicone-dimensional(1D)andtwo-dimensional(2D)arraysonthebasisoflinearelasticity.Each 1D 60DCParrayalwayshaslowerenergythanitshomogeneouscounterpart.Thesituationofeach2D array(containingtwomutuallyorthogonal1Darrays)dependsontheperioddifference d betweenthe two individual1Darraysandthefilmthickness.If dΒΌ0, each2D60DCParrayhashigherenergythanits homogeneouscounterpart,whereasthe2D60DCParrayisenergeticallymorefavorableforalarger d and/orathickerfilm.Theanalysissuggestsasemiconductor-processingstrategytoobtain901 dislocation-dominantarraysandtoreduceTDs.Furthermore,basedonthecriterionofzeroenergy changebyinsertingthelastdislocationtocompleteanarray,wecalculatetheequilibriumarrayperiod for variousconfigurations,implyingpossiblestrainover-relaxation(4100%-relaxedcondition)fora sufficientlythickfilm.

Main Author: Feng, Gang.
Other Authors: Freund, L.
Language: English
Published: 2007
Online Access: http://ezproxy.villanova.edu/login?url=https://digital.library.villanova.edu/Item/vudl:176104