CAREER: Perovskite Buffer Layers for Compound Semiconductor-Silicon Heteroepitaxy

这项研究计划将研究钙钛矿缓冲层在硅上半导体化合物异质外延中的应用。钙钛矿缓冲层为解决异质外延中的晶格失配问题提供了潜在的解决方案。在硅上生长钙钛矿薄膜的过程中，氧扩散到界面，形成一个非晶态的SiOx区域，将钙钛矿外延层与硅衬底分开。然后，钙钛矿层可以作为后续外延层(例如化合物半导体)的模板。研究计划将确定非晶态SiOx界面是否充分缓解了外延层中产生的晶格失配应变，并在界面处捕获了位错缺陷。因此，钙钛矿“缓冲层”可以在硅衬底上实现低缺陷密度的异质外延。这项技术具有巨大的潜力，可以创造出将光学有源器件与硅cmos逻辑的能力相结合的新设计。这项研究将为金属有机化学气相沉积和原子层沉积方法用于锶成核层和钛酸锶缓冲层的生长提供新的科学认识。实验研究将开发在硅上成功生长高质量的外延钙钛矿层所必需的化学和反应工程基础。钙钛矿缓冲层将用作III-V/硅异质外延的衬底。调查将分析锶和钛有机金属前驱体的气相和表面反应化学。研究工作将通过反应堆的设计和运行来优化材料质量。特殊的挑战包括控制前体向反应区的传输，避免过早形成和/或分解加合物，以及获得高质量的单晶外延层。

This research program will investigate the use of perovskite buffer layers for compound semiconductor-on-silicon heteroepitaxy. Perovskite buffer layers offer potential solutions to lattice mismatch challenges in heteroepitaxy. During the growth of perovskite films on silicon, oxygen diffuses to the interface and creates an amorphous SiOx region that separates the perovskite epitaxial layer from the silicon substrate. The perovskite layer can then act as a template for subsequent epitaxial layers such as compound semiconductors. The research program will determine if the amorphous SiOx interface sufficiently relieves the lattice mismatch strain generated in the epitaxial layers and also traps dislocation defects at the interface. Perovskite "buffer" layers may therefore enable low defect density heteroepitaxy on silicon substrates. The technology has enormous potential to create new designs that integrate optically active devices with the power of silicon CMOS logic. The research will provide new scientific understanding of metalorganic chemical vapor deposition and atomic layer deposition methods to be used for the growth of strontium nucleation layers and SrTiO3 buffer layers. Experimental investigations will develop the chemistry and reaction engineering fundamentals necessary for successful growth of high quality epitaxial perovskite layers on silicon. The perovskite buffer layers will be used as substrates for III-V/silicon heteroepitaxy. Investigations will analyze the gas phase and surface reaction chemistry of the strontium and titanium organometallic precursors. Research efforts will optimize the materials quality through reactor design and operation. Special challenges include controlling precursor transport to the reaction zone, avoiding premature adduct formation and/or decomposition, and achieving high quality monocrystalline, epitaxial layers.