Uniaxial and Hydrostatic Stress on Group III-nitride Heterojunctions and Schottky Barriers

III 族氮化物异质结和肖特基势垒的单轴应力和静水应力

• 批准号: 0140164
• 负责人: Marshall Nathan
• 金额: $ 22.5万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-15 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0140164&HistoricalAwards=false
• 关键词: Uniaxial; Hydrostatic; Stress; Group; III

Abstract-0140164M. Nathan, U of Minnesota-Twin CitiesDevices based on III-nitride semiconductors have great potential for many applications in optoelectronics and power electronics. Polarization effects in these materials provide new opportunities for new device designs and raise challenges for existing ones. At present, while a qualitative understanding of these effects exists to some extent, a complete quantitative model and experimental characterization is lacking. The main thrust of this proposal is directed at a quantitative understanding of polarization effects in III-nitride compounds.Polarization effects and nitride-based devices are inextricably connected with dominant effects in heterojunction FETs, heterojunction bipolar transistors, and lasers. Consideration of spontaneous and piezoelectric effects is therefore imperative in device design. In addition to high-power, high-temperature electronic devices, we envision possible applications of these phenomena in stress (or force) sensors, such as those needed for accelerometers and seismic detectors intended to operate in caustic environments.We propose a coordinated experimental and theoretical investigation of electric polarization effects in III-nitride heterostructures and Schottkv barriers. Our study will address lattice polarization effects on charge carrier transport at heterojunction interfaces in structures with currents either parallel or perpendicular to the interfaces. Examples of structures to be fabricated and tested will include n- and p-channel single heterostructures, metal/semiconductor Schottky contacts on III-nitrides, and n+- and p+Si/III-nitride Schottky contacts. To avoid possible surface contamination, Al/III-nitride and Si/III-nitride contacts will be fabricated in situ, i.e. without removing the samples from the ultra-high vacuum environment. For reasons discussed in this proposal, we view these latter structures (with the non-polar/polar interface grown in situ following III-nitride epitaxy) as particularly promising for the study of III-nitride surface polarization charges. We will measure the uniaxial and hydrostatic stress dependences of the electrical characteristics of these structures. Exploring different stress geometries will advance the understanding of piezoelectric effects in III-nitride compounds. Our physical model development will address band structure and electric polarization effects and their consequences for the terminal characteristics of the devices under uniform and non-uniform, uniaxial and hydrostatic stress. The characterization and modeling work builds on capabilities developed by the PIs over the last 11 years in the context of their past and ongoing joint exploration of piezoelectric effects in conventional III-V heterostructures. The crystal growth for this program will performed by Professor Hadis Morkoq's group at Virginia Commonwealth University.The proposed research will involve both graduate and undergraduate students, and will enhance the PIs ongoing course development with focus on large gap semiconductor materials and devices.

摘要-0140164M。明尼苏达大学双城分校内森基于 III 族氮化物半导体的器件在光电子和电力电子领域的许多应用中具有巨大潜力。这些材料中的偏振效应为新器件设计提供了新的机会，同时也给现有器件提出了挑战。目前，虽然对这些效应有一定程度的定性理解，但缺乏完整的定量模型和实验表征。该提案的主旨是定量理解 III 族氮化物化合物中的极化效应。极化效应和氮化物基器件与异质结 FET、异质结双极晶体管和激光器中的主导效应有着千丝万缕的联系。因此，在设备设计中必须考虑自发效应和压电效应。除了高功率、高温电子设备之外，我们还设想这些现象在应力（或力）传感器中的可能应用，例如在腐蚀性环境中运行的加速度计和地震探测器所需的传感器。我们提出对 III 族氮化物异质结构和肖特克​​势垒中的电极化效应进行协调的实验和理论研究。我们的研究将解决电流平行或垂直于界面的结构中异质结界面上电荷载流子传输的晶格极化效应。待制造和测试的结构示例包括n沟道和p沟道单异质结构、III族氮化物上的金属/半导体肖特基接触以及n+和p+Si/III族氮化物肖特基接触。为了避免可能的表面污染，Al/III 氮化物和 Si/III 氮化物触点将在原位制造，即无需将样品从超高真空环境中取出。由于本提案中讨论的原因，我们认为后一种结构（在 III 族氮化物外延后原位生长的非极性/极性界面）对于 III 族氮化物表面极化电荷的研究特别有前景。我们将测量这些结构的电气特性的单轴和静水应力依赖性。探索不同的应力几何形状将促进对 III 族氮化物压电效应的理解。我们的物理模型开发将解决能带结构和电极化效应及其对均匀和非均匀、单轴和静水应力下器件终端特性的影响。表征和建模工作建立在 PI 在过去 11 年中开发的能力的基础上，这些能力是他们过去和正在进行的对传统 III-V 异质结构压电效应的联合探索的背景下。该项目的晶体生长将由弗吉尼亚联邦大学的 Hadis Morkoq 教授的团队进行。拟议的研究将涉及研究生和本科生，并将加强 PI 正在进行的课程开发，重点关注大能隙半导体材料和器件。