GOALI: Strained Layer Heterostructures for GaN-on-Si Epitaxy

目标：用于 GaN-on-Si 外延的应变层异质结构

• 批准号: 1410765
• 负责人: Joan Redwing
• 金额: $ 39万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1410765&HistoricalAwards=false
• 关键词: GOALI; Strained; Layer; Heterostructures; GaN

Non-technical Description: Gallium nitride is an important semiconductor due to its wide ranging applications in solid-state lighting and power electronics. Pennsylvania State University and Efficient Power Conversion (EPC) Corporation are partnering in this GOALI project to develop materials growth technology to integrate gallium nitride thin films with silicon wafers, which are the standard substrates used for integrated circuit fabrication. The ability to directly combine these two materials would allow flexibility in circuit design for a variety of applications. However, the hexagonal crystal structure of gallium nitride is incompatible with the cubic crystal structure of (100) silicon. This project seeks to overcome these limitations by intentionally introducing strain into the silicon to alter the surface structure and thereby reduce the crystal mismatch. Real-time wafer curvature measurements are used to directly measure strain in the silicon substrate and study dynamic changes in film stress during gallium nitride deposition. Post-growth structural characterization is used to elucidate mechanisms of stress generation and relaxation. The project supports the Ph.D. thesis work of two graduate students at Penn State University who are exposed to issues relevant to process scale-up and manufacturing in a global semiconductor foundry through the collaboration with EPC. Undergraduates and high-school students from underrepresented groups and economically challenged regions of Pennsylvania are participating in the research through summer programs at Penn State University. Technical Description: This GOALI project is on the epitaxial growth of AlGaN/GaN heterostructures on on-axis (100) Si substrates for hybrid power electronics circuits. Strained Si/SiGe virtual substrates are being explored as a route to control the dominant reconstruction of the (100) Si surface and thereby reduce the in-plane rotational misalignment of AlN nuclei. In-situ wafer curvature measurements are used to monitor stress relaxation in the SiGe layers and measure tensile strain in the Si layer at the growth temperature and study its impact on GaN/AlN heteroepitaxy. The effects of n-type dopant chemistry on stress evolution in GaN are also being examined. The project seeks a fundamental understanding of the role of Si surface strain on GaN/AlN epitaxy, which can then be exploited to develop AlGaN/GaN two-dimensional electron gas heterostructures on (100) Si for power devices. The project team has complementary expertise in group III-nitride heteroepitaxy on Si substrates (Penn State University) and process scale-up and commercialization of GaN-on-Si for power field-effect transistors (EPC). In addition, EPC is well positioned to capitalize on hybrid circuit designs that will be enabled by the GaN on (100) Si growth technology developed in this project.

非技术描述：氮化镓是一种重要的半导体材料，在固态照明和电力电子领域有着广泛的应用。宾夕法尼亚州立大学和高效电源转换（EPC）公司在这个GOALI项目中合作开发材料生长技术，将氮化镓薄膜与硅晶片集成，硅晶片是用于集成电路制造的标准衬底。直接联合收割机这两种材料的能力将允许用于各种应用的电路设计的灵活性。然而，氮化镓的六方晶体结构与（100）硅的立方晶体结构不相容。该项目旨在通过有意地将应变引入硅中来改变表面结构，从而减少晶体失配来克服这些限制。实时晶片曲率测量用于直接测量硅衬底中的应变，并研究氮化镓沉积期间膜应力的动态变化。生长后的结构表征用于阐明应力产生和松弛的机制。该项目支持博士学位。宾夕法尼亚州立大学的两名研究生的论文工作，他们通过与EPC的合作，接触到了与全球半导体代工厂的工艺放大和制造相关的问题。来自宾夕法尼亚州代表性不足的群体和经济困难地区的本科生和高中生通过宾夕法尼亚州立大学的暑期项目参与了这项研究。 技术说明：该GOALI项目是关于AlGaN/GaN异质结构在轴向（100）Si衬底上的外延生长，用于混合电力电子电路。应变Si/SiGe虚拟衬底被探索作为控制（100）Si表面的主要重构的途径，从而减少AlN核的面内旋转未对准。原位晶片曲率测量被用来监测应力松弛的SiGe层和测量拉伸应变的Si层在生长温度和研究其对GaN/AlN异质外延的影响。n型掺杂剂化学对GaN中应力演化的影响也正在研究中。该项目旨在从根本上了解Si表面应变对GaN/AlN外延的作用，然后可以利用它来开发AlGaN/GaN二维电子气异质结构（100）Si功率器件。该项目团队在硅衬底上的III族氮化物异质外延（宾夕法尼亚州立大学）以及用于功率场效应晶体管（EPC）的硅基GaN工艺放大和商业化方面具有互补的专业知识。 此外，EPC已做好充分准备，利用该项目开发的GaN on（100）Si生长技术实现的混合电路设计。