Structural and electrical evaluation of the influence of carbon delta layers for defect reduction on epitaxial growth of thin, relaxed germanium layers on silicon substrates

碳δ层对硅衬底上薄的松弛锗层外延生长缺陷减少影响的结构和电学评估

基本信息

批准号：
389061803
负责人：
Professor Dr. H. Jörg Osten
金额：
--
依托单位：
Institut für Materialien und Bauelemente der Elektronik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/389061803?language=en
关键词：
Structural electrical evaluation influence carbon

项目摘要

The interest in the integration of germanium into silicon-based semiconductor technology is driven by the idea to continue the miniaturization in silicon MOS technology by use germanium MOSFETs with enhanced channel mobility or to extend the application portfolio of said technology by the integration of optoelectronic circuits based on germanium. Moreover, relaxed germanium layers on silicon are suited as virtual substrates for III-V materials yielding additional benefits for photovoltaics.Direct growth of germanium on silicon for device applications is ruled out as the difference in lattice constant leads to three-dimensional islanding and generation of numerous crystal defects after only a few monolayers. Device capable film quality can still be obtained using graded buffer layers. A strong reduction of growth temperature also leads to smooth germanium films, which have to be annealed subsequently at higher temperatures. While the first approach suffers from the large buffer thickness, the second is afflicted with the onset of interdiffusion between silicon and germanium during post-growth annealing. Alternatively, the use of surfactants can suppress islanding during growth. Unfortunately, the best surfactants are also dopants for silicon and germanium, thus incorporation during growth ends up with background doping. This project aims at the use of carbon delta-layers as defect filters in the epitaxy of thin relaxed germanium films on silicon substrates. It originates in our recently developed method of carbon-mediated epitaxy, which combines low-temperature growth with an island-preventing submonolayer coverage of carbon. This method enables extremely thin smooth relaxed germanium films on silicon avoiding potential background doping. In addition, our recent results indicate that carbon delta-layers can block the vertical propagation of dislocations in the germanium film. This project focuses on the investigation of the fundamental mechanisms of this effect. An optimized number and distance of carbon delta-layers together with an optimum amount of carbon in each delta-layer will lead to germanium films with the best possible structural properties considering roughness and defect density. A second key aspect is the electrical characterization of germanium films grown by carbon-mediated epitaxy. In particular, we center on the impact of carbon on carrier mobility and recombination processes that could evoke additional leakage in pn-junctions. As final result, an evaluation of the achievable figures of merit and the application potential of relaxed germanium films grown by carbon-mediated epitaxy is aspired.

通过将葡萄球菌MOSFET与增强的通道迁移率一起使用的晶型MOS技术，通过将硅胶技术整合到基于硅的半导体技术中的兴趣是驱动的。此外，硅上的松弛锗层适合于III-V材料的虚拟底物，从而为光伏而产生额外的益处。葡萄干在硅上的直接增长用于设备应用，因为晶格常数的差异导致三维岛化的差异，仅在几次单层后产生了众多晶体缺陷。仍然可以使用分级缓冲层获得能力的膜质量。生长温度的强烈降低也导致光滑的锗膜，随后必须在较高的温度下退火。虽然第一种方法遭受了较大的缓冲厚度，但第二种方法遭受了生长后退火期间硅和锗之间延伸的发作。或者，表面活性剂的使用可以在生长过程中抑制岛化。不幸的是，最好的表面活性剂也是硅和锗的掺杂剂，因此在生长过程中掺入后面以背景掺杂。该项目的目的是将碳三角层用作硅底物上薄片薄膜的外观中的缺陷过滤器。它起源于我们最近开发的碳介导的外观上的方法，该方法将低温的生长与碳预防群的碳覆盖率结合在一起。这种方法使在硅上的极其薄的光滑松弛锗膜避免了潜在的背景掺杂。此外，我们最近的结果表明，碳三角层可以阻止锗膜中脱位的垂直传播。该项目着重于研究这种效果的基本机制。碳三角层的优化数量和距离以及每个三角层中最佳碳的最佳碳将导致具有最佳结构特性的锗膜，考虑粗糙度和缺陷密度。第二个关键方面是通过碳介导的外观延强而生长的锗膜的电特性。特别是，我们以碳对载体迁移率和重组过程的影响为中心，这些过程可能会引起PN缝隙中的额外泄漏。作为最终结果，对碳介导的外交生长的可实现的功能数字以及放松的锗膜的应用潜力的评估很兴奋。