Competing relaxation mechanisms in strained layers.
Competing relaxation mechanisms in strained layers.
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DOI：
10.1103/physrevlett.72.3570
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发表时间：
1994-05
影响因子：
8.6
通讯作者：
J. Tersoff;F. Legoues
中科院分区：
文献类型：
--
作者：
J. Tersoff;F. Legoues
我们发现应变外延层可以通过两种相互竞争的机制来松弛。在较大的失配时，表面变得粗糙，从而容易位错成核。然而，应变诱导的表面粗化是热激活的，随着失配的减少，势垒迅速增加。因此，在某些失配${\mathrm{\ensuremath{\varepsilon}}}_{\mathit{c}}$，以下，应变通过在表面有时间粗化之前在现有源上的位错成核来松弛。通过表面粗化来松弛在技术上是不可取的；我们将讨论温度、表面活性剂或成分分级如何改变${\mathrm{\ensuremath{\varepsilon}}}_{\mathit{c}}$，从而控制松弛模式。
We show that strained epitaxial layers can relax by two competing mechanisms. At large misfit, the surface becomes rough, allowing easy nucleation of dislocations. However, strain-induced surface roughening is thermally activated, and the energy barrier increases very rapidly with decreasing misfit \ensuremath{\varepsilon}. Thus below some misfit ${\mathrm{\ensuremath{\varepsilon}}}_{\mathit{c}}$, the strain relaxes by nucleation of dislocations at existing sources before the surface has time to roughen. Relaxation via surface roughening is technologically undesirable; we discuss how temperature, surfactants, or compositional grading change ${\mathrm{\ensuremath{\varepsilon}}}_{\mathit{c}}$ and so control the mode of relaxation.