ITR: Materials for InAs MOSFETs: The Enabling Transistor for Low Power, 100 GHz+ Information Transfer and Processing

该项目研究了一系列气相沉积氧化物在锑基半导体合金“ABCS”（InAs、GaSb、AlSb及其合金）上形成的原子和电子结构；目的是了解氧化三元半导体界面费米能级解钉的基本机制。需要充分了解相关的界面化学问题，以便预测哪些氧化物是在InAs器件结构的通道和约束层上形成非固定界面的最佳候选者。推测亚氧化物分子插入到表面二聚体中，破坏了表面重构，恢复了体晶对称性，钝化了氧化物/半导体界面，从而形成了无钉住的氧化物- abcs界面。任务1：确定用于钝化的亚氧化物（Al2O、Ga2O、In2O、Tl2O、SiO、GeO、TiO）和“ABCS”表面（AlSb、GaSb、InAs或其合金）的最佳组合，将对一系列亚氧化物和表面进行计算。这些计算将确保每个候选亚氧化物破坏二聚体重建，解开费米能级，并且不取代二聚体原子。对于Ga2O/GaAs，这已经成功地完成了。任务2：为了确定任务1中确定的亚氧化物表面组合沉积的最佳重建和温度，将使用组合膜生长。亚氧化物将气相沉积在原子清洁、有序的表面上。扫描隧道显微镜（STM）和光谱学（STS）将被用来确定沉积后和不暴露于空气中的表面的原子和电子结构。沉积将在几个表面重建上进行测试。任务3：将与任务1中开发的亚氧化物兼容的厚（30至100A）绝缘栅氧化物层沉积在最佳的氧化物-半导体表面上，并进行电容和跨导测量以表征氧化物-半导体界面。这项工作将利用NRL在InAs HEMT加工和InAs/GaAs晶圆生长方面的广泛知识库。此外，所有电路测试将与摩托罗拉合作完成。该项目的一个重要影响是通过研究和教育的整合在教育和人力资源开发方面。学生在化学、物理或电气工程部门工作的多学科性质的研究提供了广泛的教育机会。通过暑期项目活动，我们做出了特别的努力，以确保参与项目的学生的多样性。为了促进学生与工业的关系，PI还指导了一个工业互动日，将在材料化学，物理和工程领域工作的加州大学圣地亚哥分校研究生和在工业领域工作的应届毕业生（英特尔，LSI， IBM， HRL，安捷伦，应用材料和novacystals）聚集在一起。这一天包括由学生和工业科学家进行的演讲。与ITR（信息技术研究）相关的技术包括无线通信、遥感网络、个人数字助理和毫米波成像阵列，以及高频（100千兆赫）逻辑、带有传感器和遥测技术的微型飞行器（用于检测环境污染物和化学/生物战剂）。以及具有局部信号处理功能的微型传感器（用于化学/生物武器检测或用于医学诊断的皮下植入）。这些设备都需要高速、低功耗的逻辑，这是该项目的研究活动所实现的，特别是与ITR随时随地提供关键信息和优化工作效率的目标相关。* * *

This project addresses atomic and electronic structures formed by a series of vapor deposited oxides onto antimony based semiconductor alloys, "ABCS" (InAs, GaSb, AlSb, and their alloys); the aim is to achieve understanding of basic mechanisms of Fermi level unpinning of oxide-ternary semiconductor interfaces. Related interfacial chemistry issues need to be sufficiently understood to allow prediction of which oxides are best candidates to form unpinned interfaces on channels and confinement layers in InAs device structures. It is conjectured that to grow an unpinned oxide-ABCS interface, sub-oxide molecules insert into surface dimers, break the surface reconstruction, restore the bulk crystal symmetry, and passivate the oxide/semiconductor interface. Three tasks are envisioned: Task 1: To determine the best combinations of sub-oxides (Al2O, Ga2O, In2O, Tl2O, SiO, GeO, TiO) and "ABCS" surfaces (AlSb, GaSb, InAs or their alloys) for passivation, calculations will be performed on a series of sub-oxides and surfaces. These calculations will ensure that each candidate sub-oxide breaks the dimer reconstruction, unpins the Fermi level, and does not displace dimer atoms. This has been done successfully for Ga2O/GaAs. Task 2: To determine the optimal reconstruction and temperature for deposition of sub-oxide-surface combinations identified in Task 1, combinatorial film growth will be used. Sub-oxides will be vapor deposited onto atomically clean, ordered surfaces. Scanning tunneling microscopy (STM) and spectroscopy (STS) will be employed to determine both the atomic and electronic structure of the surface after deposition and without exposure to air. Deposition will be tested on several surface reconstructions. Task 3: A thick (30 to 100A) layer of an insulating gate oxide compatible with the suboxide developed in Task 1 will be deposited on the best oxide-semiconductor surfaces and capacitance and transconductance measurements will be made to characterize the oxide-semiconductor interface. This work will utilize the expansive knowledge base of the NRL in InAs HEMT processing and InAs/GaAs wafer growth. Additionally, all circuit testing will be done by collaboration with Motorola. %%% An important impact of the project is in education and human resource development through the integration of research and education. The multi-disciplinary nature of the research where students work in chemistry, physics, or electrical engineering departments provides broad educational opportunities. Special efforts are made to ensure the diversity of students working on the project through summer program activities. To foster student-industrial relations the PI also directs an industrial interaction day bringing together UCSD graduate students working in materials chemistry, physics, and engineering and recent graduates working in industry (Intel, LSI, IBM, HRL, Agilent, Applied Materials, and Novacrystals). The day consists of talks that are given by students and industrial scientists. Technological relevance to ITR (Information Technology Research) includes wireless communication, remote sensor networks, personal digital assistants, and mm-wave imaging arrays, as well as high frequency (100 GHz) logic, micro air vehicles with sensors and telemetry (for detection of environmental pollutants and chemical/biological warfare agents), and microscopic sensors with local signal processing (either for chemical/biological weapons detection or for subdermal implantation for medical diagnostics). These devices all require high speed, low power logic enabled by the research activities of this project with particular relevance to the ITR goals of delivery of critical information anytime, anywhere and optimization of work efficiency. ***