Reduced dislocation introduction in III-V/Si heterostructures with glide-enhancing compressively-strained superlattices
Reduced dislocation introduction in III-V/Si heterostructures with glide-enhancing compressively-strained superlattices
复制标题
通过增强滑移的压缩应变超晶格减少 III-V/Si 异质结构中的位错引入
DOI：
10.1021/acs.cgd.0c00992
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发表时间：
2020
影响因子：
3.8
通讯作者：
Grassman, Tyler J
中科院分区：
文献类型：
--
作者：
Boyer, Jacob T;Blumer, Ari N.;Blumer, Zak H.;Lepkowski, Daniel L.;Grassman, Tyler J
GaAsyP 1-y/GaP压应变超晶格（CSS）的新用途是在GaP/Si变质异质外延过程中提供对失配位错（MD）演化和穿透位错密度（TDD）的增强控制。在临界厚度之后插入CSS，从而在引入大量位错之前，发现与可比较的对照样品相比，在松弛的500 nm厚的n型GaP/Si中产生显著降低的TDD。研究了CSS周期数对平均TDD和整体位错网络形态的影响，并得到了定量微观结构表征的支持，结果表明，3周期CSS结构的相对TDD减少了近20倍（至（2.4 ± 0.4）× 106 cm-2）。当用所得的n-GaP/Si虚拟衬底生长双端型GaAs_（0.75）P_（0.25）-端GaAsyP_（1-y）渐变变质缓冲层时，仍保持同样低的TDD（（3.0 ± 0.6）× 106 cm ~（-2））。虽然由这些结构提供的TDD减少的物理机制尚未完全理解，这个初步的工作表明，增强滑移动力学的MD在或内的CSS放置在生长早期导致减少的位错总数引入整体，而不是基于湮灭的减少，发生在传统的应变层超晶格位错过滤器的方法。
The novel use of a GaAsyP1–y/GaP compressively strained superlattice (CSS) to provide enhanced control over misfit dislocation (MD) evolution and threading dislocation density (TDD) during GaP/Si metamorphic heteroepitaxy is demonstrated. Insertion of the CSS just after critical thickness, and thus prior to substantial dislocation introduction, is found to yield significantly reduced TDD in relaxed, 500 nm thick,n-type GaP/Si versus comparable control samples. The impact of CSS period count on average TDD and the overall dislocation network morphology was examined, supported by quantitative microstructural characterization, revealing a nearly 20× relative TDD reduction (to (2.4 ± 0.4) × 106cm–2) with a 3-period CSS structure. A similarly low TDD ((3.0 ± 0.6) × 106cm–2) is maintained when the resultantn-GaP/Si virtual substrate is used for the growth of a subsequentn-type GaAs0.75P0.25-terminal GaAsyP1–ystep-graded metamorphic buffer. Although the physical mechanism for TDD reduction provided by these structures is not yet entirely understood, this initial work suggests that enhanced glide dynamics of MDs at or within the CSS placed early in the growth leads to a reduction in the total number of dislocations introduced overall, as opposed to annihilation-based reduction that occurs in conventional strained-layer superlattice dislocation filter approaches.